doc. Ing. Jan VOŠTA, CSc. (*1940 - †2016)
1986 - 1991 vedoucí Katedry energetiky
1991 - 1997 vedoucí Ústavu energetiky
2002 - 2005 vedoucí Ústavu energetiky
Narozen v roce 1940 v Táboře.
Absolvoval reálné gymnázium v Táboře a Fakultu technologie paliv a vody VŠCHT v Praze. Po absolutoriu v roce 1962 nastoupil jako vědecký aspirant a obhájil kandidátskou disertační práci na téma „Příspěvek k hodnocení mořících inhibitorů“ v roce 1965. V roce 1978 obhájil habilitační práci s názvem „Studium inhibitorů koroze pro moření parních generátorů“ a téhož roku byl jmenován docentem pro obor „Tepelná technika“.
V roce 1973 mu byla udělena cena Emila Votočka.
Sajdl, P., Janda, V., Vosta, J., Macak, J., Racek, J. Corrosion inhibitor for natural gas recovery, transportation and storage facility (2011), patent CZ 302855 B6 20111214.
In the present invention, there is disclosed a corrosion inhibitor for natural gas recovery, transportation and storage facility contg. 45 to 55 percent by wt. of propargyl alc., 23 to 27 percent by wt. of dimethylbenzyllaurylammonium bromide, 20 to 26 percent by wt. of triethanolamine phosphate and 0.5 to 1.0 percent by wt. of fatty acid alkanolamide. In case of more corrosive environment, the inhibitor of the present invention further comprises 0.2 to 0.5 percent by wt. of ethanolamines, and optionally 0.2 to 0.5 percent by wt. of octadecylamine in the form of 10 percent emulsion.
Macak, J., Janda, V., Vosta, J. Removal of deposits and inhibition of corrosion on heat-exchange surfaces of power plants (2011), patent CZ 302805 B6 20111116.
The invented method for removing deposits on heat-exchange surfaces of power plants and inhibition of corrosion of these plants in which water is used with a Hp value adjusted to alkali region is characterized in that organophosphonic acids are added to water during continuous cleaning in an amt. of 2 to 5 mg per 1 L of a circulating and/or cooling medium, which organophosphonic acids prevent pptn. of deposits of carbonate nature onto heat-exchange surfaces or due to reaction thereof with calcium and magnesium ions the heat-exchange surfaces can optionally be cleaned, and in that there are also added compds. of chelating nature being selected from the group consisting of nitrilotriacetic acid (NTA), EDTA (EDT), hydroxyethylenediaminetriacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), etylenediaminetetraphosphonic acid or salts thereof in an amt. of 5 to 10 mg per 1 L of the circulating and/or cooling medium, and further polyacrylamides in an amt. of 0.5 to 10 mg per 1 L of the cooling medium. Further, there is advantageous to add 10 percent octadecylamine emulsion, zinc anion or, particularly for nuclear steam generators, hydrogen peroxide.
Macak, J., Janda, V., Vosta, J. Composition for alkalization and anti-corrosive protection of power generating equipment (2011), patent CZ 302467 B6 20110601.
A compn., which is intended for alkalization and anti-corrosive protection of power generating equipment, in 1 L of water contains 0.1-5 g of a volatile alkalization agent selected from the group consisted of piperidine, ammonium, hydrazine, or morpholine, 0.1-5 g of a film-forming amine selected from the group consisted of octadecylamine, dioctadecylamine, hexadecylamine, dodecylamine, and derivs. thereof, and 0.1-5 g of polyethylene glycol and/or ethoxylated fatty acids, and/or ethoxylated fatty alcs. enabling emulsification of amines and increasing their adherence to the equipment surface. In order to enhance the emulsification capability, the compn. further contains 0.1-5 g of alkanolamide of coconut oil acids functioning as a surface-active agent. Preferably, the compn. further contains 0.1-5 g of ethanolamine and derivs. thereof, prolonging alkalization of the equipment surface. When using the compn. for low-pressure and medium-pressure boilers and high-pressure barrel-type boilers, it is advantageous to add NaOH and/or Na3PO4·12H2O.
Buryan, P., Vosta, J., Vodrazka, S., Svozil, L. Means against settlement of deposits Petroleum and Coal (2010), 52(3), 179-182.
A new method for removing high mol. org. deposits left by crude oil and natural gas with the help of a new patented prepn.
Macak, J.,Pazderova, M., Jiricek, I., Maly, P., Olysar, K., Cvrcek, L., Vosta, J., Corrosion properties of physically deposited thin coatings Chemické Listy (2007), 101(9), 713-721.
A review. Sputtering, the 1st invented phys. vapor deposition (PVD) coating technol. was known for >150 years. Although the PVD and related technologies were commercialized for over 70 years, their expansion in the last 20 years has become enormous - from decorative and cutting tool to special optical applications and microelectronics. This is due to their excellent properties such as chem. inertness, hardness, tribol., tribochem. and optical properties. In many applications the PVD coatings are exposed to corrosive environments. Also, PVD coatings of environment-friendly nature are often considered to be potential successors of Cd-based anticorrosion coatings. This fact promotes numerous studies of corrosion properties of thin coatings. Hard coatings (including nitrides, carbides and oxides) are usually more corrosion-resistant than the base material. Some of them (e.g. Ti nitride, the most common PVD coating) have columnar microstructure which brings about the possibility of high micropore d. In local defects and/or pores, local corrosion can be promoted by galvanic effects. This type of hard coatings is useless for anticorrosion purposes. As perspective anticorrosion coatings, PVD-deposited Al-based coatings are frequent subjects of studies. Similarly to Cd coatings, they usually provide sacrificial properties, which can be enhanced by alloying with Mg. Tribol. properties and corrosion resistance can be enhanced by alloying with Mo. Given the excellent flexibility, adaptability of PVD technol. and its ability to deposit multilayers or graded coatings, new coatings with functional properties comparable with traditional anticorrosion coating systems could be developed.
Buryan, P., Vosta, J., Vodrazka S. Composition for removal of high-molecular organic deposits from crude oil and natural gas (2007), patent CZ 297597 B6 20070110.
A compn. is disclosed for removing high-mol. org. deposits from crude oil and natural gas. The compn. contains ≥50 wt.% hydrocarbon mixt. b.120-320° at a pressure of 101.325 kPa and 0.001-10 wt.% ≥1 surface-active compd. based on reaction products of fatty acids and amines. The surface-active compd. also contains both free initial amines and fatty acids. Preferably, the compn. also contains 0.003-3 wt.% defoaming agent selected from a group of C1-10 alcs. Further, the compn. also contains 0.0002-5 wt.% corrosion inhibitor selected from a group consisting of propargyl alc., propargyl alc. dissolved in ≥1 C1-10 alc., and/or dibenzosulfoxide dissolved in ≥1 C1-10 alc. The deposits are treated with the compn. at a temp. ranging from -20 to 130° and at a pressure of ≤21.00 MPa. The compn. is suitable for prodn., transportation, storage, and refining of crude oil and natural gas.
Pohorely, M.; Vosecky, M.; Hejdova, P.; Puncochar, M.; Skoblja, S.; Staf, M.; Vosta, J.; Koutsky, B.; Svoboda, K. Gasification of coal and PET in fluidized bed reactor Fuel (2006), 85(17-18), 2458-2468.
Blended fuel comprising 23 wt.% polyethyleneterephthalate (PET) and 77 wt.% brown coal was gasified in an atm. fluidized bed gasifier of lab.-scale. The gasification agent was composed of 10 vol.% O2 in bulk of nitrogen. Thermal and texture analyses were carried out to det. the basic properties of the fuel components. The influence of exptl. conditions, such as the fluidized bed and freeboard temps. on major and minor gas components and tar content, as well as features of the blended fuel gasification in comparison with the single coal gasification, were studied. In the case of coal with PET gasification, only the fluidized bed temp. showed significant influence on CO, CO2, CH4 and H2 content in the producer gas, whereas the effect of the freeboard temp. was insignificant. In single coal gasification both temps. had considerable and almost the same influence. The content of minor components, such as ethane, ethylene, acetylene and benzene, was found to be more dependent on the freeboard temp. than on the fluidized bed temp. It was obsd. that the higher the freeboard temps. get, the lower is the concn. of the minor components, with the exception of acetylene. The abs. contents of almost all minor and tar components were approx. three times higher in blended fuel gasification than that in single coal gasification. Finally, partition of carbon (char) and selected metals into bottom and cyclone ash in gasification of both fuels is discussed.
Smrz, M., Vosta, J., Nemec, M., Urban, P., Method of extract production with content of terpene and humin substances (1992), patent CS 275233 B2 19920219.
Smrz, M.,Vosta, J., Macak, J., Pelikan, J.,; Vavrin, J., Lohnisky, J.,Novotny, M., Horak, Z., Vana, O. et al. Corrosion inhibitor for energetic gases' exploitation,transportation and storage equipment (1991), patent CS 274680 B2 19910915.
Vosta, J., Smrz, M., Horak, Z., Slama, O. Method of anticorrosive steel protection (1991), patent CS 274321 B1 19910411.
Varga, L., Smrz, M., Vosta, J., Mares, O. Agent for steel surfaces cleaning (1991), patent CS 274320 B1 19910411.
Smrz, M.,Vosta, J. Method of steel's corrosive inertization (1991), patent CS 274319, B1 19910411.
Smrz, M., Vosta, J., Bartos, M., Non-toxic anticorrosive agent (1991),patent CS 274318, B1 19910411.
Vosta, J., Smrz, M., Oliva, L., Horak, Z.,Pelikan, J., Macak, J.,Viden, I., Kratochvil, J., Vavrin, J. Directional corrosion inhibitor (1990),patent CS 268318 B1 19900314.
Smrz, M., Vosta, J., Simana, J. Method of glands' and packings' asbestic segments' anticorrosion and hygienic treatment (1990), patent CS 268317 B1 19900314.
Pelikan, J.,Smrz, M., Slama, O., Vosta, J. Alkaline preservation liquid (1990), patent CS 268316 B1 19900314.
Macak, J., Sajdl, P., Kucera, P., Novotny, R., Vosta, J. In situ electrochemical impedance and noise measurements of corroding stainless steel in high temperature wate Electrochimica Acta (2006), 51(17), 3566-3577.
An in situ corrosion study of austenitic stainless steel 08CH18N10T in high temp. H2O was performed. The material under study is used in the construction of steam generator of PWR (pressurized H2O reactor) nuclear power stations and is similar to AISI 321 stainless steel. In situ 300-h tests were performed under autoclave conditions at 280° and 8 MPa and consisted of impedance measurements, polarization measurements and electrochem. noise measurements. The expts. were performed in deionized H2O with the pH adjusted to 9.5, in the presence/absence of chlorides. An addnl. modification of corrosivity was achieved by changing oxygen concn. A detailed anal. of the impedance data is presented identifying in the impedance spectra contributions of oxide, corrosion reaction, double layer and diffusion process. A good agreement was found between corrosion data from electrochem. impedance spectroscopy (EIS) and that from electrochem. noise (EN) measurements. The oxide response cannot be attributed to the overall oxide layer but only to the part corresponding to the space charge layer, thus indicating the semi-conductive character of the oxide.
Novotny, R., Sajdl, P.,Vosta, J., Macak, J. The initiation and propagation of stress corrosion cracks in high temperature and high pressure conditions, Edited Moody, N. R. , Hydrogen Effects on Material Behavior and Corrosion Deformation Interactions, Proceedings of the International Conference on Hydrogen Effects on Material Behavior and Corrosion Deformation Interaction, Moran, WY, United States, Sept. 22-26, 2002 (2003), 791-798.
This work represents a study of environmentally assisted cracking in high temp. and high pressure conditions by Rising Displacement Tests (RDT). It appeared that the crucial part of RDT was crack initiation point definition. The aim of these expts. was threshold stress intensity factor KISCC, and threshold value calcd. from J integral KJSCC detn., crack growth kinetics detn. by ACPD technique, and evaluation of the influence of various displacement rates on tests results. We tested two kinds of materials: reactor pressure steel 15ChNMFA and austenitic stainless steels A316H in various environments, primary circuit soln. VVER 1000 (15Ch2NMFA) and water soln. with defined Cl- concn. (100 mg/l in case of A316H stainless steel). We used the ACPD technique for crack initiation and propagation observation. The specimens were analyzed by optical microscopy and SEM after concluding of the expt. Reactor pressure steel 15Ch2NMFA is susceptible to stress corrosion cracking. Stress corrosion crack initiation and propagation was obsd. along the whole fracture surface. We managed to det. that the threshold intensity factor KJSCC equals 63 MPa.m1/2. We achieved good agreement with similar tests carried out in Nuclear Research Institute. Expts. with stainless steel AISI 316H were only partly successful. We achieved stress corrosion crack initiation in expts. with low displacement rates. Problems appeared in Expts. with high displacement rates because of large plastic strain zone generation at the crack tip shortly after beginning the expt.
Machnikova, E.; Koutsky, M.; Hrdlicka, F.; Vosta, J. Combustion efficiency and emissions in the combustion of biomass in stoves Chemické Listy (2003), 97(3), 171-178.
The paper presents mass and enthalpy balances in the combustion of biomass in stoves. The first part of the paper concerns the biomass as an alternative source of energy, the combustion processes, formation of emissions and the method of calcn. of mass and enthalpy balances. In the second part, exptl. data are presented involving four types of fuels: foliate pellets, mixed pellets, "American" pellets and sludge pellets of the bituminous coal type. The efficiency of the stove was calcd. for all the fuels by using mass and enthalpy balances. In addn., anal. of products of incomplete combustion, such as CxHy, volatile org. compds., persistent org. pollutants (polycyclic arom. hydrocarbons, polychlorinated biphenyls, polychlorinated dibenzodioxines and dibenzofurans) was performed.
Triskova, J., Niznansky, D., Novotna, M., Macak, J., Vosta, J. Spectroscopic study of iron oxide scale composition on inner surfaces of steam pipes Koroze a Ochrana Materialu (2002), 46(3), 57-61.
Compn. of an oxide corrosion scale on the inner surfaces of steam generator pipes was examd. by using Moesbauer spectroscopy and IR spectroscopy. The scale compn. depended on operation conditions of power plants. Both methods are suitable for detn. of genesis and morphol. of the scale. The main components were magnetite and hematite. The oxide scale was thin, compact, and cryst.
Mutombo, P.; Sajdl, P.; Vosta, J.; Matocha, K. The effect of dibenzylsulfoxide and sodium phosphate on the stress corrosion cracking of steels Anti-Corrosion Methods and Materials (1998), 45(1), 38-40.
The inhibition of stress corrosion cracking of steels 22K and 0Ch18N10T in citric acid and sodium chloride was investigated. The effect of dibenzylsulfoxide (I) and Na3PO4 inhibitors was established by means of the slow strain rate technique. I decreases susceptibility of the steels to stress corrosion. Na3PO4 inhibits stress corrosion of 22K, but increases the susceptibility of 0Ch18N10T steel to stress corrosion.
Mutombo, P.; Pospisil, L.; Fiedler, J.; Cejka, J.; Karhan, J.; Vosta, J. The polarographic behavior of the corrosion inhibitor dibenzyl sulfoxide Journal of Electroanalytical Chemistry (1996), 405(1-2), 223-226.
D.c. and a.c. polarog. data confirm that the corrosion inhibitor dibenzyl sulfoxide is reducible in its protonated form at the mercury electrode. The two-electron redn. process yields dibenzyl sulfide as the major product. Both oxidized and reduced forms are strongly adsorbed on mercury and exert inhibition properties for the hydrogen evolution reaction.
Mindl, J., Vosta, J., Kutej, P.,Davidek, J. Study of the ecologically benign inhibitors of corrosion Chemické Listy (1995), 89(8), 518-25.
The work presents the use of the natural substances as inhibitors of corrosion. These substances are food-industry products, semiproducts or wastes. Electrochem. methods (polarization curves, EIS spectroscopy), wt.-loss method, and Moessbauer spectroscopy were used for studying inhibition behavior. Expts. have shown that the best inhibitors among the substances are beery yeast, gelatin, bone glue and ext. from the spruce crust. Org. natural substances are non-toxic and cheaper than com. inhibitors but are less biol. stable.
Jiricek, I.; Vosta, J.; Macak, J.; Fikar, J.; Liska, F. Ecologically acceptable N-based compounds in corrosion inhibition in acidic media, Annali dell'Universita di Ferrara, Sezione 5: Chimica Pura ed Applicata, Supplemento (1995), 10(8th European Symposium on Corrosion Inhibitors, 1995, Vol. 1), 235-44.
Selected amides of fatty acids with 16-18 carbon atoms in mol. and mol. wt. of 300-400 were investigated to find a perspective ecol. supplement to corrosion inhibitors used nowadays in acidic environments. Wt.-loss, potentiodynamic polarization, impedance spectroscopy and hydrogen penetration were among the methods used in the study. Results show that good protection can be expected from all org. compds. investigated. Inhibition efficiency of 90-97% at room temp. can be expected. Effectiveness is decreased with increasing temp. Addn. of inhibitor into soln. also affects hydrogen transport through the carbon steel sheet material.
Macak, J.; Vosta, J.; Hackerman, N. A study of iron corrosion inhibition by some aromatic nitriles From Annali dell'Universita di Ferrara, Sezione 5: Chimica Pura ed Applicata, Supplemento (1995), 10(8th European Symposium on Corrosion Inhibitors, 1995, Vol. 1), 179-85.
The inhibition effects of benzonitrile (BN), 1,2-dicyanobenzene (1,2-DCB), 1,4-dicyanobenzene (1,4-DCB) and of 7,7,8,8-tetracyanoquinodimethane (TCNQ) on the corrosion of pure polycryst. iron (99.9985%) in hydrochloric acid was studied by the electrochem. polarization and impedance spectroscopy techniques. The inhibition was found to decrease in the following sequence: BN > 1,4-DCB > 1,2-DCB > TCNQ. The polar properties of the mols. and energies and coeffs. of the MOs calcd. by means of EHT method were taken into account in the discussion.
Pingo, M.; Vosta, J.; Pancir, J.; Haslingerova, I. Topological study of crack growth on iron crystal Applied Surface Science (1995), 90(3), 373-6.
The aim of this work consists in theor. calcns. of the charge distribution in the crack of an Fe semi-infinite crystal by using the quantum topol. MO-LCAO method to formulate general ideas on corrosion mechanisms during the Stress Corrosion Cracking. The model suggested describes the cracking by a successive removal of atoms in the direction of a slot formation. It appears that at. charges are substantially changed in the course of slot formation which can cause the increase of the reactivity of corrosion particles as the crack is formed.
Kutej, P.; Vosta, J.; Pancir, J.; Hackerman, N. Electrochemical and quantum chemical study of propargyl alcohol adsorption on iron Journal of the Electrochemical Society (1995), 142(6), 1847-50.
A quantum chem. topol. method was used to det. probable adsorption modes of propargyl alc. at an Fe surface. Based on the results, the most probable adsorption mode is one in which both carbon atoms forming triple bonds interact with the surface Fe atom. Another important finding is that the adsorption seems to be possible only at a surface partially covered by adsorbed H. Chronoamperometric expts. were used to study current changes resulting from injection of inhibitor at different potentials. Results support the relation between the presence of adsorbed H and inhibitor sorption and indicate that adsorption of propargyl alc. is reversible.
Kutej, P.; Vosta, J.; Pancir, J.; Macak, J.; Hackerman, N. Electrochemical and quantum chemical study of dibenzyl sulfoxide adsorption on iron Journal of the Electrochemical Society (1995), 142(3), 829-34.
Electrochem. techniques (potentiodynamic polarization curves and electrochem. impedance spectroscopy (EIS)) were used to study the effect of dibenzyl sulfoxide adsorption on the dissoln. of iron in 5% hydrochloric acid. To discuss different proposed mechanisms of dibenzyl sulfoxide adsorption at the iron surface a quantum chem. topol. method was used, which is suitable for studying the interaction of org. mols. with metal surfaces. Based on the results of the topol. modeling, adsorption followed by redn. of dibenzyl sulfoxide to sulfide is most favorable. EIS shows the possible effect dibenzyl sulfoxide has on the electrochem. desorption of adsorbed hydrogen. Topol. studies indicate strengthening of the bond of the adsorbed hydrogen to the metal due to adsorption of the inhibitor.
Kutej, P.; Vosta, J.; Bartos, M. Reactivity of organic substances at the surface of metal Edited by Costa, Josep M.; Mercer, Antony Donald, Prog. Understanding Prev. Corros., [Pap. Eur. Corros. Congr.], 10th (1993), 2, 896-9.
Various org. substances were studied by electrochem. methods in acid environment (5% HCl) as corrosion inhibitors. The most interesting substance proved to be propargyl alc. (PG), not only for its efficiency, but also for its action at the interface. A quantum chem. approach was used to explain this activity.
Smrz, Milan; Vosta, Jan; Macak, Jan; Pelikan, Josef; Kudlicka, Jaroslav Corrosion passivation of steel (1991), patent CS 272104 B1 19910115.
Steels in a carbonate-contg. medium are passivated by enrichment of the medium by adding 150-1500 mg Fe3+/L. Optionally, the enrichment is done by electrochem. generation of ions for 0.5-10 min at a c.d. of 0.5-10 A/m2. Thus, C steel exposed to an aq. soln. contg. 20 K2CO3 and 10% KHCO3 was passivated by adding 500 mgFe3+/L soln. in the form of an EDTA complex at 65°. The passivation was more efficient than that attained with conventional K2CrO4.
Vosta, J., Smrz, M., Kurfurst, A., Kubis, R., Hanes, I. Reducing agents in acid pickling and cleaning baths for the systems containing steel and copper parts (1991), CS 274988, B2 19911217.
The aq. baths contain an inorg. acid or C1-C6 carboxylic acid 3-15, a corrosion inhibitor (esp. sulfoxide and/or quinoline deriv.) 0.01-1, and an org. reducing agent 0.2-5%. The reducing agent acts as a corrosion inhibitor for steel, and reduces Fe3+ ions in the soln. to prevent corrosion of Cu and its alloys. A descaling and pickling bath for corroded heat exchangers is typically aq. 15% HCl, and contains dibenzyl sulfoxide 0.2, benzyldimethyllaurylammonium chloride 0.1, and hydrazine hydrate (as reducing agent) 0.5%. The corrosion inhibition in this bath is 96% for C steel and 93% for Cu, vs. 87 and 39% resp. in the absence of reducing agent.
Pelikan, J., Macak, J., Vosta, J. Corrosion and corrosion inhibition of aluminum alloys for central heating radiators Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1990), D58, 175-90.
The corrosion resistance of Al alloys, used for central heating radiators, was studied by using an electrochem. technique and by using circuits in which actual operation conditions were simulated. Both types of expts. were also used for estn. of effectiveness of a corrosion inhibitor mixt. of benzotriazole, Na silicate, and phenylacetic acid. Electrochem. characteristics were obtained from anodic polarization data and polarization resistance measurements. Parameters of the elec. macroelements Al alloy/brass and Al alloy/steel, and time dependence of the gas vol. were detd.
Smrz, M., Vosta, J.,; Cimicka, H. Deposits and corrosion damage of steam turbine blades Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1990), D58, 191-208.
The effect of deposits and their chem. compn. on cracking of steam turbine blades was evaluated. Various deposits on AK1 steel blades from low-pressure and high-pressure sections were analyzed. The deposits from failed blades contained considerably more SiO2. However, each type of pptd. deposits originating from feed water and fatigue loading of blades resulted in stress corrosion cracking.
Bartos, M., Macak, J., Vosta, J. Effect of chemical structure of organic compounds on the corrosion inhibition of metals Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1990), D58, 139-65.
In a review with 67 refs., a relation between chem. structure of org. compds. and their effectiveness as corrosion inhibitors is discussed. Use of quantum chem. calcns. with various approxns., semiempirical methods, and empirical methods for evaluation is described.
Macak, J., Vosta, J., Smrz, M., Pelikan, J.,; Hluchan, V., Vymetal, J., Vavrin, J. Corrosion inhibitor for fuel gas production (1991), patent CS 270917 B1 19900814.
The corrosion inhibitor consists of abietic acid (I) 5-45, dibenzylsulfoxide (II) 0.5-7, heterocyclic N bases 10-30, condensation products of C2-8 alkenylamines and C8-22 fatty acids 5-50, aliph. C8-22 amines 0.5-7, and morpholine (III) 0.5-15 wt.%. The corrosion inhibitor is sol. in org. solvents down to -15°, and condensation products of alkenylamine and fatty acids hydrolyzed at elevated temps. function also as corrosion inhibitors. Thus, the corrosion inhibitor was prepd. by mixing a 5% II soln. in quinoline bases d. 243-253° 17, III 15, I 36, a condensation product of diethylenetriamine with fatty acids 25, and octadecylamine (as 10% soln. in EtOH) 7 wt.%. The corrosion inhibitor was added to a model aq. soln. of AcOH, NaCl, and Na2S. Efficiency of corrosion inhibition for C steel specimens was 97.1%.
Macak, J., Vosta, J., Smrz, M., Pelikan, J., Hluchan, V., Vymetal, J., Vavrin, J. Corrosion inhibitor for petroleum atmospheric distillation equipment (1991), patent CS 270916 B1 19900814.
The corrosion inhibitor consists of dibenzylsulfoxide (I) 0.5-10, heterocyclic N bases 10-40, C2-8 amines as an alkalization component 20-60, and optionally surfactants 0.5-35 wt.%. The amines neutralize HCl(g), formed by hydrolysis of chlorides in petroleum during distn., to form noncorrosive alkylammonium chlorides which also have a synergistic effect on the adsorption components of the inhibitor (i.e., T + heterocyclic N bases). The surfactants have also a synergistic effect. Thus, 10 ppm corrosion inhibitor consisting of a 7% I soln. in quinoline bases b. 245-275° 30, diethylamine 50, and a condensation product of diethylenetriamine and oleic acid (as surfactant) 20 wt.% was added to a model soln. simulating a water condensate during atm. distn. of petroleum. Efficiency of corrosion inhibition for C steel specimens was 96.4%.
Matocha, K., Hluchan, V., Wozniak, J., Jiricek, I., Vosta, J. Effect of the medium on the crack-growth resistance of steel CSN 41 6445 Kovové Materiály (1991), 29(4), 271-7.
The fatigue crack growth rate was studied in CSN 416445 steel exposed to stress corrosion in water in a lab. autoclave at 295°. The kinetics of fatigue crack growth in a secondary water circuit (pH 9, dissolved O < 15 ppm) in a pressurized-water nuclear reactor were only insignificantly influenced by the corrosion medium. Susceptibility of the steel to stress corrosion cracking was not obsd. An increase of the dissolved O content to 8 ppm resulted in fatigue crack growth, esp. at low frequencies. Stress corrosion cracking was identified as a major factor for degrdn. in the air-satd. environment.
Smrz, M., Vosta, J., Grym, I., Svoboda, K., Kudlicka, J., Vek, V. Corrosion inhibitor for carbon dioxide scrubbers (1990), patent CS 263098 B1 19890414.
The corrosion inhibitor contains 50-99.9 wt.% of benzotriazole, mercaptobenzothiazole (I), mercaptobenzimidazole or their derivs., and 0.1-50 wt.% of a surfactant contg. ≥1 quaternary ammonium compds., sulfosuccinic acid esters, alkylarylsuflfonates, heterocyclic N compds. (e.g., quinolines, isoquinolines, and pyridines), arom. sulfoxides, alkali metal phosphates, or alkali metal borates. The corrosion inhibitor is suitable for protection of steel parts used in CO2 scrubbers, esp. during H manuf. by steam reforming of hydrocarbons. The inhibitor is nontoxic, does not interfere with activators for the K2CO3 scrubbing soln., and is easily removed from the spent scrubbing soln. by pptn. with CO2+. Thus, 200 ppm mixt. of I 75, quinoline distn. residue 15, and dimethylaurylbenzylammonium hydroxide 10 wt.% was added to a scrubbing soln. for CO2 removal. The anticorrosion efficiency for steel parts was 99.4%.
Vosta, J., Pelikan, J., Macak, J. Thiocyanato and mercapto compounds as inhibitors for iron corrosion in hydrochloric acid Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1989), D57, 271-80.
Use of thiocyanato and mercapto compds. as corrosion inhibitors for 99.999% Fe in 5% HCl was evaluated by using polarization potentiodynamic curves. The 4-thiocyanatoaniline, 6-aminothiophenol, and 4-thiocyanotolbenzoic acid had suitable inhibition properties. According to quantum chem. data, the compds. in a nonprotonized state acted as electron donors during sorption on Fe. The protonized forms of substituted anilines were considered in the quantum calcns.
Pelikan, J., Vosta, J., Vanek, F. Inhibition of class 15 steel corrosion in hydrofluoric and hydrochloric acids on RDE [rotating disk electrode], Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1989), D57, 237-53.
Pickling of CSN 15121 boiler steel by 2% HF or 5% HCl was investigated under laminar flow conditions. To inhibit corrosion, several inhibitors were investigated. In the case of HF, pitting corrosion was obsd. Efficiency of the most inhibitors was 95-98%. Corrosion in HCl was evaluated according to the corrosion elec. current and slope of the linear portion of the polarization curves.
Vosta, J. Time dependence of the electrical double-layer capacitance during corrosion inhibition from the standpoint of quantum chemistry Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1989), D57, 281-4.
Capacitance of the elec. double-layer in dependence of time is discussed from the standpoint of quantum chem. Measurements were performed by the single pulse method at a no. of p-substituted anilines as inhibitors of iron corrosion in 6N hydrochloric acid at a temp. of 25° at the corrosion potential. The values of HOMO orbital computed by the LCAO method to the considered compds. are in agreement with the capacitance measurement. With lower sorption i.e. with lower inhibition, i.e. with increased capacitance value, the energy of the HOMO orbital decreased.
Vosta, J.; Hackerman, N. The dependence of capacitance on time in an acid inhibition corrosion process Corrosion Science (1990), 30(8-9), 949-50.
The HOMO and double layer capacitance are given for para-substituted anilines (e.g. SH, SCN, NH2, OH, Br, COCH3, NO2, CH3, H, SO3H). Corrosion measurements were performed by the single pulse method of these para-substituted inhibitors of Fe corrosion in 6N HCl at 25°. With lower sorption, and consequent lower inhibition and increased capacitance value, the energy of the HOMO is on the decrease and hence the donor capability of this series of compds. is progressively less.
Vosta, J., Pelikan, J.,Smrz, M. Pyridine derivatives as inhibitors of iron corrosion in hydrochloric acid Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1989), D57, 255-70.
The corrosion inhibitor action of pyridine and its derivs. for 99.99% Fe in 5% HCl was investigated by using polarization potentiodynamic curves. Isonicotinic acid nitrile and 4-acetyl pyridine were the best inhibitors. To support the inhibiting action, the Hammett consts. were used and correlated with the Tafel slope in the cathodic and anodic parts. The quantum chem. evaluation confirmed the accepting effect in the sorption of compds.
Laskafeld, D., Slepanek, A., Vosta, J. Manufacture of high-purity chlorosilanes (1989), patent CS 261343 B1 19890112.
The title manuf. comprises purifying liq. and gaseous chlorosilanes, before further being used, as well as mixts. of chlorosilanes with other gases, by microfiltration through a microfilter which is resistant to the filtering media. The microfilter is preferably a polyfluorohydrocarbon having pores
Talasek, V., Vosta, J.,Mostecky, J. Corrosion and erosion inhibitor (1989), patent CS 259679 B1 19881014.
Piperidine (I) is used as a corrosion inhibitor, erosion inhibitor, and volatile alkalization agent for steam-water circulation systems in elec. power plants. I is added in the form of a dild. aq. soln. into the water section of the steam-water circuit to obtain pH 9-9.2. Thus, 2 mg I/L water was added to a system generating steam at 4.7 MPa and 259°. The corrosion-erosion rate (as metal wt. loss) was decreased by 60% by using I.
Pelikan, J., Vosta, J., Hluchan, V., Corrosion inhibitor for aluminum alloys in aqueous medium (1989), patent CS 258861 B1 19880916.
The corrosion in a closed heating system contg. a circulating aq. medium is prevented by adding Na phenylacetate (I) 30-80, Na2SiO3 40-100, and 1,2,3-benzotriazole (II) 5-15 mg/L. The circulating water in an Al alloy radiator is mixed with I 60,Na2SiO3 60, nd II 10 mg/L, and no corrosion was obsd. after long-term service.
Bartos, M., Macak, J., Vosta, J., Pelikan, J. Study of an inhibited corrosion reaction. IV. Evaluation of the behavior of p-halo-substituted anilines using an a.c. impedance technique Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1988), D56, 291-321.
Sorption reaction of p-halogen substituted anilines on the surface of an Fe rotating disk electrode in 5% HCl was investigated by means of the faradaic impedance method. Values of corrosion currents were detd., from polarization measurements. Impedance spectra were measured at open circuit potential and at anodic and cathodic polarizations /at c.d. ± 1,2 mA.cm2/. It was shown, that inhibition efficiency increases in this homol. series from aniline to p-iodoaniline. This result was confirmed by the correlation of exptl. data with the values of Hammet-substituent consts.
Laskafeld, D., Vosta, J., Slepanek, A. Etching of silicon rod before crystal growth (1987), patent CS 238329 B1 19851113.
After cleaning with a surfactant and rinsing with demineralized H2O, Si rods are etched ≥5 min with H at ≥10 kPa and ≤15 L H/h-cm length. The procedure is suitable for cleaning before crystal growing of polycryst. Si for semiconductors. The resulting polycryst. Si is readily transformed to single-crystal Si. Thus, Si rods prepd. by drawing from a Si melt in Ar, conventional cleaning with a 0.1-5% Na octadecenyl-8-sulfonate soln. in H2O at 60°, rinsing with distd. or demineralized H2O, and holding ≥24 h in a polyethylene bag at 60-80° were etched 30 min with H at 1180°, 10 kPa, and 15 L H/h-cm length. After decreasing the temp. to 1100°, 0.1 mol fraction trichlorosilane was added. After 60 min, the trichlorosilane mol. fraction was increased to 0.25, and polycryst. Si was subsequently produced.
Vosta, J., Pelikan, J., Varga, L., Smrz, M., Holinka, M., Hluchan, V., Peca, M. Passivation of brass tubes for heat exchangers (1987), patent CS 234628 B1 19850416.
After cleaning with pressurized water, brass heat exchange tubes (esp. condenser tubes in elec. power plants) are passivated by treatment with 0.5-5% H2SO4, HCl, and/or citric acid in the presence of corrosion inhibitors selected from 1,2,3-benzotriazole (I) 0.1, dibenzylsulfoxide (II) or quinoline 0.1, and/or benzimidazole (III) 0.1 g/L. The passivated heat-exchanger tubes are flushed with purified water and passivated again for 1-6 h in aq. soln. contg. I 0.1, tannin 0.1, and coco fatty acid alkanolamides 0.5 g/h. The passivation mixt. is suitable for protection during long shutdown periods, startup periods of new elec. power plant equipment involving frequent interruption of service, or as a const. addn. in the cooling circuit during service. Thus, 0.6% H2SO4 soln. contg. I 0.1, II 0.1, and III 0.1 g/L was used for final cleaning of brass condenser tubes. After draining the soln., the condenser was flushed with purified water until the effluent was neutral. The tubes were then passivated by circulating aq. soln. contg. I 0.1, tannin 0.1, and coco fatty acid alkanolamides 0.5 g/L for 5 h.
Maly, K., Kocica, J., Vosta, J. Comparison of agents used in cooling systems with high content of recirculating water Vodni Hospodarstvi: B (1987), 37(5), 136-8.
The addn. of 50 mg/L Dukoin 10 (Czechoslovak dispersant) to circulating cooling water decreases corrosion of steel and stabilizes Ca and Mg thus decreasing the scale formation. Since it contains no PO43-, the dispersant is ecol. more acceptable than the highly effective agents Nalco D 4513 or Aktiphos 652. The Kurizet S 113 K dispersant is a less effective corrosion inhibitor than Dukoin 10, but it also containes no phosphates.
Nemcova, J.,Bartonicek, R., Sverepa, O., Kulhavy, T., Sladeckova, A., Novotny, M., Lohnisky, J., Paulovic, M., Panacek, F., Vosta, J. Corrosion inhibitor with sequestrating effect for copper and its alloys (1986), patent CS 233153 B1 19850214.
Aq. corrosion at pH 6-8 of Cu or Cu alloys is prevented without foulant deposition. Thus, cooling water was treated with 2-mercaptobenzothiazole at 1:20 to 4:3 and a surfactant at 0.01-0.06 kg/L; the corrosion of Cu and brass was decreased by 85-99% and the foulant deposition was decreased by 79-95%.
Nemcova, J., Bartonicek, R.,Sverepa, O., Kulhavy, T., Sladeckova, A., Novotny, M., Lohnicky, J., Paulovic, M., Panacek, F., Vosta, J. Corrosion inhibitors with sequestration and dispersing effect (1986), patent CS 233152 B1 19850214. S
The corrosion inhibitors contg. H3PO4 or salt, carboxylic acid, and a surfactant prevent corrosion and fouling by cooling water in steel or brass pipes. Thus, a mixt. contg. H3PO4 30 kg, Na3PO4 20, citric acid 5, and ethylene oxide-propylene oxide copolymer 45 kg was dispersed into 1000 m3 cooling water to show decreases of scale deposits by 80% and corrosion by 89% for steel pipes.
Varga, L., Vosta, J., Holinka, M., Pelikan, J., Smrz, M., Panacek, F. Decreasing the corrosion aggressivity of cooling media in power system condensers (1987), patent CS 234627 B1 19850416.
The corrosion rate was decreased by up to 70% by feeding benzothiazole inhibitors and other additives into the circulating water of power system condensers during interrupted performance. EDs, based on 1 ton water, are: (a) 30 g Na salt of mercaptobenzothiazole; (b) 25 g 1,2,3-benzotriazole (I); (c) 2 g I, 2 g tannin, and 6 g coco fatty acid alkanolamides; (d) 50 g Na hexametaphosphate and 5 g I; or (e) 20 g N-contg. condensates.
Bartonicek, R., Nemcova, J., Vosta, J., Paulovic, M., Sebo, T., Spacir, J., Maly, K., Kulhavy, T.,; Panacek, F., et al. Agent with corrosion-inhibiting, dispersing, and sequestering effects (1986), patent CS 231112 B1 19841015.
The corrosion of steel heat exchangers by cooling water is prevented by an inhibitor consisting of C2-3 alkylene oxide copolymers (250-3000 mol. wt.), such as ethylene oxide-propylene oxide copolymer 50-90, C2-8 alkanolamine phosphates, such as diethanolamine phosphate 5-30, and alk. polyphosphates, such as Na hexametaphosphate 0.5-20 wt.%. The inhibitor efficiency is increased by 0.5-10% C2-9 alkylphenol phosphate, such as nonylphenol phosphate, or C12-20 ethoxylated amine, such as ethoxylated hexadecylamine. The inhibitor concn. is 3-100 g/m3. Thus, 1000 m3 with water was treated with 1:1 ethylene oxide-propylene oxide copolymer 25, triethanolamine phosphate 15, and Na hexametaphosphate 10 kg to decrease the corrosion of steel by 85 and the deposition of org. substances and Ca salts by 70%. Other components in various proportions were also used, such as Na tripolyphosphate, ethoxylated hexadecylamine, monoethanolamine or diethanolamine phosphate, and nonylphenol phosphate.
Vosta, J., Smrz, M., Pelikan, J., Kapounova, H., Kleprlik, Z., Hluchan, V., Eliasek, J. Removal of copper deposits from boiler surfaces in power plants (1986), patent CS 236422 B1 19850515.
Aq. cleaning bath for Cu removal is composed of 0.05-0.5% diperoxyacetic acid (I), 0.05-10% NH4OH, 0.05-5% ethylenediaminetetracetic acid salts or nitriletriacetic acid (II), and optionally 0.05-5% H2O2. Thus, boiler tubes were treated with aq. bath composed of 0.2% I, 0.2% NH4Cl, and 0.4% II before etching with 2.5% HF to remove Cu completely from the surface.
Hluchan, V., Vosta, J., Pelikan, J.,Smrz, M., Nemcova, J. Stress-corrosion cracking inhibitor (1986), patent CS 228745 B1 19840514.
Stress cracking of steel in acid and chloride-contg. media is inhibited in the presence of alkanolamines, thiazoles, quinoline derivs., amines, and (poly)amides. Thus, inhibitor mixt. contained triethanolamine 28.5, mercaptobenzothiazole 15, coco fatty acid alkanolamide 2, crude quinoline fraction 18, octadecylamine 28.5, and polyacrylamide 8 parts. At 0.1% concn. the mixt. gave 91% corrosion inhibition, and prevented for 29 days the crack formation in tensile-stressed specimens of austenitic stainless steel in an aq. soln. contg. 2.5 M H2SO4 and 0.5 M NaCl.
Cervinka, J., Pelikan, J., Hluchan, V., Vosta, J. Corrosion of ferritic steels in products of the sodium-water reaction Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1985), D51, 215-34.
The corrosion resistance was studied of the ferritic steels Type 1Ch2M, Type W.St. Nr. 1.6770, and Type 15418. These steels are used in fast reactor steam generators. The changes of mech. properties were detd. from material loss. All steels exhibited at 340-480° similar corrosion resistance. The corrosion was dependent exponentially on temp, and the steels exhibited good resistance against stress corrosion cracking at ≤400° and a load of 80% of the limit σ0.2. The corrosion resistance of steels is sufficient for the case of a steam generator accident.
Macak, J., Bartos, M., Vosta, J., Vondrak, J. Study of sorption kinetics by the a.c. impedance technique Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1985), D51, 235-45.
The a.c. impedance method was used to study the adsorption of thiourea from adsorbing and nonadsorbing electrolyte solns. on a Hg electrode. The impedance data were analyzed graphically and by using a computer. The impedance of the a.c. circuits and the shapes of the frequency-impedance dependences were used to monitor the time dependence of the thiourea adsorption in the presence of adsorbing and nonadsorbing electrolytes and to det. the factors controlling sorption. The kinetics of thiourea adsorption evidently is controlled by a mixed diffusion-kinetic process. In the case of sorption from nonadsorbing electrolytes the kinetic component is relatively more significant. The adsorption of thiourea from adsorbing electrolyte is controlled mainly by diffusion.
Vosta, J., Pelikan, J., Smrz, M., Nemcova, J., Varga, L. Passivating and corrosion inhibiting agent for heat exchangers of brass (1986), patent CS 223221 B1 19830915.
A 1:1:2 mixt. of benzotriazole, tannin, and coconut fatty acid alkanolamides is added at 20 ppm. to cooling water. Corrosion protection is comparable with results from alkali chromates that show ecol. problems.
Hluchan, V., Pelikan, J., Vosta, J. Mechanism of stress corrosion cracking Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1985), D51, 199-214.
Austenitic stainless steels e.g. 18-8 are sensitive to stress corrosion cracking (SCC) in environments contg. Cl-, SO42-, OH-, etc., and therefore this study was made in 2.5M H2SO4 + 0.5M NaCl. The exptl. work was concerned with the several known methods of detn. of SCC and results supported the view that SCC occurs in the Cl-/SO42- environments by destroying the protection layer and by anodic local dissolving. The crack propagation rates (CPR) were calcd. in the active and passive regions and the effect of 10-2M K2CrO4 on the redn. of CPR is also discussed.
Nemcova, J.,Bartonicek, R., Vosta, J., Kulhavy, T. Corrosion inhibitor for steel, copper and alloys with dispersing and complexing effects (1985), patent CS 226394 B1 19840319.
The corrosion inhibitor contains C2-8-alkanolamine mercaptobenzothiazolate or alkali metal mercaptobenzothiazolate 3-25, C1-8-alkanolamine phosphate 10-30, and a surfactant 45-87%. Thus, diethanolamine mercaptobenzothiazolate 2.4, triethanolamine phosphate 8, and 1:1 ethylene oxide-propylene oxide copolymer 69.6 kg were added to a 4000-m3 aq. medium in a cooling circuit consisting of steel and Cu70Zn29Al brass parts. The amt. of deposits, steel corrosion, and brass corrosion were decreased by 80, 70, and 65%, resp.
Nemcova, J., Bartonicek, R., Vosta, J., Sverepa, O., Panacek, F., Svoboda, M., Jizba, J., Kulhavy, T., Sladeckova, A., et al. Agent with dispersion-sequestrative and corrosion-inhibitive effects (1984),patent CS 227447 B1 19840416.
Mixts. of H3PO4 or phosphates 20-50, org. hydroxy acids 20-50, alkanolamides of C6-24 fatty acids 5-30, and surfactants 5-30 parts are useful for aq. cooling medium and warrant satisfactory protection for steel, brass, and Al. Thus, treating 1000 m3 cooling water of pH 7.2 with H3PO4 15, citric acid 15, diethanolamides of coconut acids 10, and polyethylene glycol ether phosphate 10 kg decreased formation of deposits by 74%, steel corrosion by 92%, and Al corrosion by 85%.
Mostecky, J., Nemcova, J., Vosta, J., Pelikan, J., Lohnisky, J., Novotny, M., Hluchan, V., Strnadova, V. Deicing salt with a mixed corrosion inhibitor (1985), patent CS 219449 B1 19830325.
Road salt compns. with anticorrosion efficiency ≥93% toward steel, Zn, Cu, Al, and the pavement surface consist of alkali or alk. earth chlorides 98.2-99.1, alkali phosphates 0.5-0.8, inorg. Zn salts 0.3-0.6, alkali sulfites 0.05-0.3, and a base (alk. earth hydroxides, C2-8 alkanolamines) 0.05-0.1%. Thus, an aerated 3% aq. soln. of a compn. contg. NaCl 92, MgCl2 6.7, Na6P6O18 [10124-56-8] 0.7, ZnSO4 0.4, Na2SO3 0.15, and triethanolamine [102-71-6] 0.05% exhibited a ≥95% anticorrosion effect on steel, Cu, Zn, and Al.
Nemcova, J., Bartonicek, R., Holinka, M.,Sverepa, O., Mostecky, J., Pelikan, J., Vosta, J., Panacek, F., Eliasek, J.,; et al. Corrosion inhibitor for brass with a biocidal effect (1985), patent CS 222108 B1 19830429.
Corrosion inhibitors contg. alkanolamines, C12-18 alkylamines, mercaptobenzothiazoles, and surfactants prevent dezincification of brass ducts and condensers as well as their fouling with biol. deposits. Thus, triethanolamine [102-71-6] 54 was mixed at 60° with C18H37NH2 [124-30-1] 3 and 2-mercaptobenzothiazole [149-30-4] 43. The mixt. was stirred at 60° for 2 h, cooled, and mixed with monoethanolamides of coconut acids 43 parts at 40°. Using this mixt. in a brass cooler at 20 ppm in water gave 98% corrosion inhibition and 70% suppression of microbial growth.
Mostecky, J., Humhej, J., Lohnicky, J., Vosta, J., Pelikan, J., Nemcova, J., Smrz, M. Deicing agents for asphalt compositions (1985), patent CS 218692 B1 19830225.
Deicing agents for pavement consist of a core of CaCl2 or NaCl and NaOH coated with Zn stearate [557-05-1] 0.4-5, ZnSO4 0.1-3, octadecylamine [124-30-1] 0.01-0.1, and inorg. or org. peroxide 0.1-2% (per particle). Thus, asphalt compns. used for roads with long-term icing resistance and anti-corrosive effects were composed of the usual bituminous mixt. and 5% deicing granules composed of CaCl2 89.9, NaOH 5, and ZnSO4 0.7% coated with Zn stearate 4, cumene hydroperoxide [80-15-9] 0.3, and octadecylamine 0.1%.
Hluchan, V.; Pelikan, J.; Vosta, J. Corrosion and SCC of steel in hydrogen sulfide environment Proc. - Int. Congr. Met. Corros. (1984), 3, 538-42.
Corrosion inhibitors for H2S were evaluated in connection with natural gas prodn. in Czechoslovakia. The corrosion study was carried out by measuring the potentiodynamic polarization, and by the const. strain rate deformation method. The inhibitors Sever 1, Garesin, and I-21-D were the most effective.
Hluchan, V., Pelikan, J., Vosta, J. Corrosion and corrosion cracking in hydrogen sulfide environment Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1984), D50, 57-70.
The elec. polarization curves and the rates of sample elongation at const. load were used to det. the effect of com. corrosion additives on the elec. and mech. properties of steel pipes in a medium simulating a petroleum well environment (H2S satd. 5% NaCl-0.5% AcOH soln. at 25°). Of the 8 com. inhibitors tested, the best were Sever 1 [54692-93-2], Garesin [84136-89-0], and I 21-D [73989-41-0]
Vanek, F., Pelikan, J., Vosta, J. Study of point corrosion of aluminum in aqueous sodium chloride medium by measuring chemical impedance Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1984), D50, 39-55.
Chem. impedance (effect of chem. inhibitors on the elec. impedance) on an Al sample (99.99%) in a 1% NaCl medium and in the presence or in the absence of inhibitors K2CrO4 and NaNO3 in 5 × 10-2M concn. was measured. The sample was applied as a rotating disk electrode. Better knowledge of the broad dependence of impedance frequency parameters was made possible by using the method of Lissajous figures. The course of frequency impedance spectra in the presence of inhibitors corresponded to the course of a slow electrode action or to an irreversible electrode reaction. In the medium without inhibitors the course was different, giving evidence of a reaction controlled by diffusion or of a quasi-reversible electrode action.
Pelikan, J., Vanek, F., Vosta, J. Study of pitting corrosion of aluminum in aqueous sodium chloride medium by means of RDE Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1984), D50, 19-37.
The measurements of corrosion under convection by means of the rotating disk electrode (RDE) disclosed the possibility of using this electrochem. method for distinguishing the effect of corrosion inhibitors on the metal-medium interface for pitting corrosion. The combination of potentiodynamic polarization measurements and the measurement of c.d. under const. potential proved to be good for the detn. of relatively more suitable inhibitors under given conditions. The effect of inhibitors can be explained mainly by the oxidn. and chemisorption effects with simultaneous coverage of a large part of the area, and/or of the active corrosion sites, of the rotating disk Al samples. When using the inhibitors, NaNO3 proved to be more effective against pitting corrosion than K2CrO4 in the concn. of 5 × 10-2M.
Vosta, J., Pelikan, J., Macak, J., Hluchan, V., Smrz, M. Study of an inhibited corrosion reaction. III Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1984), D50, 71-82.
Corrosion inhibitors were evaluated by electrode impedance. Electrochem. measurements were performed with CSN 17246 [50947-31-4] stainless steel electrode in active and passive states in a soln. contg. 2.5M H2SO4 and 0.5M NaCl, and also with 99.9% Fe electrode in 10% HCl with the addn. of Nitrone [4745-47-5], dibenzyl sulfoxide [621-08-9], pyridine [110-86-1], and pyrrole [109-97-7] as corrosion inhibitors. Impedance dependence in the initial passive state and during transpassivation was examd.
Vosta, J.; Trabanelli, G.; Pelikan, J.; Zucchi, F.; Hluchan, V. Contribution for evaluation of some benzonitriles as corrosion inhibitors. Proc. - Int. Congr. Met. Corros. (1984), 1, 378-9.
The efficiency of benzonitriles as corrosion inhibitors for Fe in 5 N H2SO4 was studied. The HOMO orbital, which is a theor. analog to the ionization potential of a substance, was used for evaluation of exptl. results. The electron donor and acceptor action of inhibitors, and electron transfer and forming of the bond between metal and inhibitor are considered.
Mostecky, J., Pelikan, J., Vosta, J., Lohnisky, J., Nemcova, J., Smrz, M., Novotny, M. Antifreeze composition from sodium chloride and corrosion inhibitors (1984), patent CS 216579 B1 19821126.
Antifreeze compns. for road surfaces with suppressed corrosive action towards metals and concrete contain CaCl2 or MgCl2 6-8, alk. phosphates 0.3-0.6, ZnSO4 0.2-0.4, caprolactam [105-60-2] 0.1-0.7, arom. thiazoles and/or their salts 0.001-0.2, Zn stearate (I) [557-05-1] 0.01-0.05, hydroxyalkylamides of coconut oil acids, Na dodecylbenzenesulfonate [25155-30-0], and/or alkyl polyethyleneglycol ether phosphate (II) 0.01-0.15, Na2SiF6 0.0005-0.1, and NaCl up to 100%. A typical compn. comprised NaCl 92, CaCl2 6.1, (NaPO3)6 0.01, I 0.02, II 0.03, and mercaptobenzothiazole [149-30-4] 0.02% and had an anticorrosion efficiency of 93% compared to NaCl.
Nemcova, J.; Sverepa, O.; Karnikova, V.; Ptakova, J.; Vosta, J. Garesin as a corrosion inhibitor for underground gas storage tanks Korrozios Figyelo (1983), 23(1-2), 5-10.
Garesin [84136-89-0] (contg. surfactant components and org. N compds.) corrosion inhibiting efficiency was tested on C steel in liq.- and gas-phase-contg. systems as a function of aggressive components concn., temp., inhibitor concn., medium dynamics, corrosion (rust) on steel surface, and inhibitor pretreatment of steel. The aggressive components were NaCl, acetic acid, NaHSO3, and CO2. The inhibitor was very effective not only on lab. samples but under actual field expts. with underground gas storage tanks.
Vosta, J., Pelikan, J., Smrz, M., Zehle, I. Corrosion protection of metal-plated contacts in electronics (1984), patent CS 213533 B1 19820409.
The corrosion protection agent is a liq. mixt. of 0.4-0.6 g stearic acid [57-11-4], 0.6-1.0 g paraffin, and 3-5 mL bis-(2-ethylhexyl)sebacate [122-62-3] in 100 mL xylene contg. 0.04 octadecylamine [124-30-1], 0.02 lanolin, and 0.04% mixed imidazoline [28299-33-4] derivs. The agent optionally also contains 0.08% Zn stearate [557-05-1].
Vosta, J., Pelikan, J., Smrz, M., Hluchan, V., Smetana, J., Wagner, M. Anticorrosion treatment of equipment (1984), patent CS 213223 B1 19820326.
Equipment put on standby is flushed out with steam contg. film-forming C12-20 aliph. amines 50-500 and optionally an alkalizing agent (e.g., cyclohexylamine) 0.5-5 and a nontoxic, volatile, corrosion inhibitor (e.g., BzONH24) 0.5-5 g/kg steam. The treatment is esp. suitable for power and metallurgical plants. Thus, a nuclear-power-plant unit was put on standby and the system, consisting of austenitic stainless-steel components, was preserved by flushing with steam contg. 15 g octadecylamine/kg steam. Corrosion did not occur. The protective film was removed by superheated steam before returning the unit to operation.
Pelikan, J.,Vosta, J., Mostecky, J., Inhibited anticorrosive lacquer (1983), patent CS 202460 B1 19810130.
An inhibited, anticorrosive varnish, suitable for rusty, wet, or greasy metal surfaces, consists of C18H37NH2 (I) [124-30-1] or (C18H37)2NH [112-99-2] 2-20; C12-18 fatty acid or alc. ethoxylated with 15-35 mols. oxirane 0.1-0.5; the reaction products (II) of oleic acid with 1-(2-aminoethyl)-2-heptadecenyl-2-imidazoline 0.1-1; MgO 0.1-1; powd. Al, Zn, Cd, or Pb 0.02-0.5; NaNO2 0.1-2; and H2O 75-97%. Thus, a varnish comprised I 2, ethoxylated fatty acid 0.2, II 0.1, powd. Al 0.05, NaNO2 2, and H2O 95.65%.
Macak, J., Vosta, J., Pelikan, J. Smrz, M., Hluchan, V., Havlas, Z. Study of the inhibited corrosion reaction. II Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1982), D45, 99-134.
Inhibition effects and the kinetics of surface sorption corrosion reactions of tetracyanoethylene, nitron, and argenton 0.001 mol/L 5% HCl at Fe and Ni electrodes were studied by the faradaic impedance method and by measuring the elec. double layer capacitance by the single current pulse method. Only nitron showed significant inhibition effects. The results were interpreted by chemisorption of nitron (as supported by HOMO energy data).
Nemcova, J., Holinka, M., Mostecky, J., Pelikan, J., Vosta, J., Eliasek, J., Smrz, M., Lohnisky, J., Novotny, M., Mencl, F., Corrosion inhibitor for aqueous heat exchange media in brass (1983), patent CS 211962 B1 19820226.
The corrosion inhibitor contains aliph. amines, arom. azoles, surfactant, polymer, and quinoline or derivs. Thus, 1000 m3 of cooling water was treated with octadecylamine [124-30-1] 0.9, diethanolamine [111-42-2] 0.5, 2-mercaptobenzothiazole [149-30-4], 0.2, 1,2,3-benzotriazole [95-14-7] 0.2, coconut acid diethanolamide 0.05, polyacrylamide [9003-05-8] 0.05, and quinoline [91-22-5] 0.1 kg. The treatment had a 97% corrosion-inhibiting effect and did not remove Zn from the brass surface.
Havrland, B., Jara, J., Smrz, M., Vosta, J., Pelikan, J., Mostecky, J. Anticorrosion protection of metal articles (1983), patent CS 211982 B1 19820226.
The agent contains a novel mixt. of tannin and unsatd. fatty acids alkanolamides with synergetic effect. It converts Fe oxides to tannates, stabilizes rust by sorption of inhibitors, and abolishes the adverse effect of the rust layer on base paint. A typical compn. is tannin 15, coconut fatty acids alkanolamides 3, and 1,2,3-benzotriazole [95-14-7] 0.5 parts dissolved in a 40:20:21.5 mixt. of iso-PrOH [67-63-0], BuOH [71-36-3], and water.
Vosta, J., Pelikan, J., Smrz, M., Sedlacek, M. Inhibition of corrosion reactions. I Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1982), D45, 5-25.
Inhibition of corrosion was studied. Influence of structure on the inhibitor efficiency during sorption at the liq./solid interface was investigated. The internal structure was detd. by using a quantum chem. calcn. method, boundary orbitals, and mol. diagrams. Efficiency of the inhibitors was evaluated from polarization potentiodynamic curves and by measurement of the Faraday impedance. Expts. were done with 4-aminobenzonitrile [873-74-5] and 4-aminothiophenol [1193-02-8] inhibitors and Fe wire. Irreversibility of the reaction between the inhibitor and metal was explained by chemisorption.
Vosta, J., Kadija, I. V., Pelikan, J., Hackermann, N., Hluchan, V. Inhibition corrosion of iron by means of RDRE Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1982), D45, 75-97.
The rotating double ring electrode (RDRE) was used to investigate some corrosion processes in 6N HCl. The inhibitor mols. are considered from the quantum-chem. point of view. The electrochem. and quantum-chem. data were correlated to give a more general picture of the nature of corrosion inhibition. Much more exact measurements and evaluations of different inhibitors can be done by using the RDRE. Both HOMO and LUMO are of great influence on chemisorption and inhibition activity of compds. Therefore, strong electron donors and acceptors can act as good inhibitors by forming chem. bonds with the surface. The results obtained from this type of investigation can be correlated directly with the evaluation of catalytic phenomena, esp. in flowing systems.
Hluchan, V., Pelikan, J., Vosta, J. Stress corrosion cracking of steels in aqueous environments Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1982), D45, 51-74.
Nemcova, J., Sverepa, O., Mostecky, J., Pelikan, J., Vosta, J., Smrz, M., Volf, J., Safar, M., Fousek, V., et al. Bactericidal agent inhibiting corrosion of metals (1983), patent CS 202494 B1 19810130.
Corrosion-preventing agents contain an alkalizing agent, a corrosion inhibitor, a film-forming amine, and surfactant. They are esp. useful for equipment used in the drilling, storage, and transport of natural and city gas. Thus, a mixt. of cyclohexylamine [108-91-8] 30, octadecylamine [124-30-1] 20, imidazoline [504-75-6] 25, coconut acid monoethanolamide 5, and ethoxylated octadecylamine 20 parts had in 10% alc. soln. 98% protection and entirely suppressed Desulfovibrio bacteria.
Mostecky, J., Pelikan, J., Vosta, J., Smrz, M., Nemcova, J., Sverepa, O., Safar, M., Fousek, V., Demcik, Z., Slanina, F. Mixed corrosion inhibitor(1982), patent CS 207959 B1 19810831.
Corrosion inhibition of 93-95% for metals used in the transport and storage of natural gas is obtained by using a mixt. of 20-60 parts higher film-forming amines, such as cyclohexylamine and octadecylamine, 20-40 parts unsatd. fatty acid alkanolamides, and optionally 20-25 parts imidazole or imidazoline derivs. and/or 25 parts ester of fatty acids with higher alcs. as a 5% soln. in a MeOH-hydrocarbon soln. A typical corrosion inhibitor consists of cyclohexylamine [108-91-8] 30, octadecylamine [124-30-1] 30, and alkanol amide of unsatd. fatty acids in a 10% alc. solns. 40%.
Vosta, J., Pelikan, J., Mostecky, J., Nemcova, J., Smrz, M., Holinka, M. Corrosion inhibiting and bactericidal treatment of heat exchange medium (1983), patent CS 200933 B1 19801031.
Cooling and heating water systems are treated with 0.02-0.1% polyethylene oxide [25322-68-3], polyacrylamide [9003-05-8], or polyacrylonitrile [25014-41-9]. The additives markedly decrease the friction coeff. between circulating liq. and the heat-exchange surface, enhance transport of the present corrosion inhibitors and biocidal agents, and thus increased the efficiency and service life of the equipment.
Sedlacek, M. Pelikan, J.; Vosta, J. Measurement of the frequency dependence of chemical cell impedance Elektrotechnicky Casopis (1983), 34(2), 118-28.
Two methods are described for measuring the impedance of electrochem. cells consisting of a tested metal sample, a cylindrical Pt mesh ref. electrode, and corrosive electrolyte contg. corrosion inhibitors. Regulated d.c. bias voltage was applied and a small low frequency voltage superimposed. In the 0.01-500 Hz frequency range impedances were calcd. from phase relations between voltage and current. In the 100-10,000 Hz range impedances were measured with a modified de Sauty's bridge. These measurements serve for evaluation of protection efficiency of corrosion inhibitors used in boiler feed waters for power stations. These measurements are important to metallic corrosion inhibition
Pelikan, J., Smrz, M., Nemcova, J., Vosta, J., Holinka, M. Treatment of a heat-transfer medium for cooling circuits (1982), patent CS 199200 B1 19800731.
Exposing a cooling circuit to UV radiation of 150-200 W extented the protective effect of biocidal agents, such as dimethyllaurylbenzylammonium phosphate [85213-06-5] or O,O'-dimethylthiophosphate [1112-38-5]. This effect is ascribed to labilization of the lyosomal membrane of algae and bacteria by irradn. which activates lyosomal enzymes and delays adaptation of corrosion-producing organisms to the biocides.
Nemcova, J., Sverepa, O., Karnikova, V., Vosta, J., Safar, M. Garesin as a corrosion inhibitor for underground gas storage Plyn (1982), 62(12), 359-63.
Efficiency of the developed corrosion inhibitor Garesin [84136-89-0] for steel was evaluated in lab. tests by using model systems contg. NaCl, AcOH, Na2S, CO2 and in industrial tests in underground storage tanks for city gas. The inhibitor efficiency was comparable to that of com. inhibitors.
Vosta, J.,Pelikan, J., Smrz, M., Mostecky, J. Passivating agent for metal protection (1982), patent CS 200099 B1 19800829.
Mixts. of octadecylamine (I) [124-30-1] and powd. Zn, Al, or Cd have a synergic anticorrosion effect which is ascribed to the interaction of a free electron pair of the NH2 group with the active surface of the protected metal and to electrochem. protection with the dispersed metal or its oxide. Thus, structural steel is sprayed at 60° with I melt contg. 10% powd. Zn or painted with a soln. of I 10-30, powd. Al 5, and imidazoline deriv. 0.5% in CHCl:CCl2 or EtOH. Difficultly accessible spots are sprayed with an aq. emulsion contg. I 20, powd. Cd 10, Zn stearate 1, higher fatty alc.-acid esters 5, and polyethylene glycol 0.1%.
Nemcova, J., Vosta, J., Pelikan, J., Holinka, M., Rabl, V.,; Smrz, M. Anticorrosive and biocidal agent for a heat-exchanging medium (1981), patent CS 202864 B1 19810227.
Corrosion and biofouling inhibitors were formulated from allylthiourea (I) [109-57-9], coconut acid ethanolamides, PhNCO [103-71-9], and Zn dialkyl dithiophosphate. Thus, an agent contg. I 10, coconut acid ethanolamides 53, PhNCO 10, and Zn O,O-dibutyl dithiophosphate [6990-43-8] 27 parts inhibited cooling water corrosion by 90% and suppressed biofouling by 70%.
Pelikan, J., Vosta, J., Mostecky, J., Janecek, J. Removable anticorrosive coatings (1982), patent CS 196177 B1 19800331.
Removable coatings for temporary mech., anticorrosive, and antisoil protection of metal surfaces during storage and transportation contain poly(vinyl butyral) (I) 30-78, plasticizer 20-50, fillers (carbon black, bentonite) 1-20, pigments 0.01-2, dyes 0.01-2, corrosion inhibitors 0.1-3, hydrophobic agents 0.05-2, bactericides 0.1-3, and an adhesion agent 0.1-3%, and are applied as a melt or a 10-30% soln. The corrosion resistance time of metals coated with this coating increased by a factor of 21-50, compared to samples coated with common removable coatings. A typical compn. applicable as a melt comprises I 59.5, triethylene glycol di(2-ethylbutyrate) [95-08-9] 40, C18H37NH2 [124-30-1] 0.1, silicone oil 0.15, and 1-(β-aminoethy)-2-heptadecenyl-2-imidazoline oleate [84748-81-2] 0.25%.
Vosta, J., Pelikan, J., Smrz, M., Mostecky, J., Talasek, V. Bactericidal agent having an anticorrosive affect for cooling circuits (1981), patent CS 192290 B1 19790831.
An ED for 1 ton cooling water consists of an aq. emulsion contg. 2-5 g octadcylamine [124-30-1] and 0.05-0.1 g emulsifier, such as ethoxylate fatty acids or polyethylene glycol [25322-68-3]. It is combined with 5 g methylethyllaurylbenzylammonium hydroxide [81336-03-0] or 3g dimethyllaurylbenzylammonium hydroxide [500-33-4] and 2 g cetylguanidine [48073-73-0]. It may optionally contain 0.3 g p-H2NC6H4SO2NH2 [63-74-1] and 0.2 g alkyl isothiocyanate.
Safar, M. Fousek, V.,; Slanina, F.,; Mostecky, J., Pelikan, J., Vosta, J., Smrz, M., Nemcova, J., Sverepa, O. A mixed corrosion inhibitor (1981), patent GB 2064985 A 19810624.
Corrosion-inhibiting solns. for equipment in contact with coal or natural gas comprise 5-50 parts solvent/part compn. contg. ≥1 alkalizer 5-30, ≥1 C10-25 film-forming amine 5-50, and ≥1 unsatd. fatty acid alkanolamide 10-40, and optionally imidazoline derivs. 5-25 and an ester of a fatty acid with a higher alc. 5-25%. Thus, a compn. contg. cyclohexylamine [108-91-8] 30, octadecylamine [124-30-1] 30, and unsatd. fatty acid alkanolamides 40% applied as a 10% alc. soln. showed 93% inhibition efficiency in lab. tests simulating real corrosion conditions. Two other compns. are also given.
Vosta, J., Pelikan, J., Smrz, M., Horejs, J. Cooling mixture (1981), patent CS 187766 B1 19790228.
Noncorrosive cooling liq. of low eutectic temp. for cooling circuits consists of urea 10-70, corrosion inhibitors based on cyclic oligomers of H3PO4 and Zn2+ 0.1-10, and benzothiazole (I), mercaptobenzothiazole, or their derivs. 0.1-1% in 5-80% aq. EtOH or MeOH. Thus, area 50, EtOH 20, ZnSO4 0.5, Na hexametaphosphate 1, I 0.3, and water up to 100% gave the cooling mixt. applicable to -20° for corrosion-stressed systems.
Stehlik, A., Laskafeld, D.,Smaha, J., Vosta, J. High purity silicon for semiconductors (1981), patent CS 187278 B1 19790131.
Si deposits produced by reducing chlorosilanes (SiHCl3 and SiCl4) with H in the gas phase are usually contaminated with impurities which are entrained prevalently in the early stage of the redn. process. In a modified procedure, Si rods are exposed as usual to a gaseous mixt. of chlorosilanes and H having a Cl/H ratio 0.33. After 1 h the deposited Si is etched away by passing H contg. 12% HCl for 35 min, and the prodn. of Si is resumed by feeding the mixt. of chlorosilanes and H as usual.
Pelikan, J., Smrz, M.; Vosta, J. Corrosion of concrete in the presence of deicing agents Razrab. Mer Zashch. Met. Korroz., Mezhdunar. Nauchno-Tekh. Konf. Probl. SEV, 3rd (1980), 5, 270-3.
The corrosion resistance of concrete in NaCl, CaCl2, NH4NO3, EtOH [64-17-5], urea [57-13-6], urea + EtOH (AM-75), and Na2SO4solns. with f.p. -8° used as deicing agents was evaluated from detns. of pH, concrete wt. changes, and CaO and SiO2 content in solns. Min. wt. loss occurred in concrete specimens immersed in CaCl2, max. in loss NH4NO3, and intermediate losses in urea + EtOH solns. Taking into account the low aggressiveness to metals, the urea + EtOH soln. is recommended as an agent for deicing roads.
Pelikan, J., Vosta, J. Study of the inhibition of corrosion of aluminum in an aqueous chloride medium Razrab. Mer Zashch. Met. Korroz., Mezhdunar. Nauchno-Tekh. Konf. Probl. SEV, 3rd (1980), 5, 66-8.
Electrochem. methods were used to study the pitting corrosion of Al in 1% NaCl soln. The breakdown potential and the repassivation potential were established as a function of the inhibitor concns. (K chromate and NaNO3). Potentiodynamic polarization curves were also plotted.
Vosta, J., Pelikan, J. Study of corrosion inhibition using faradaic impedance Razrab. Mer Zashch. Met. Korroz., Mezhdunar. Nauchno-Tekh. Konf. Probl. SEV, 3rd (1980), 5, 30-3.
Faradaic impedance measurements yield reliable information on the nature of the bond between inhibitor and metal. Therefore, the characteristics are given of the behavior of inhibitors on the metal surfaces, i.e. the extent of soly. was detd. and the chemisorption and phys.-adsorption natures of the inhibiting reactions were established. The corrosion inhibitor di-Bu sulfoxide [2168-93-6] was selected for study because it is a good inhibitor of corrosion of Fe and steel in acid (HCl) soln.
Mostecky, J., Pelikan, J., Vosta, J., Smrz, M., Nemcova, J., Sverepa, O., Safar, M., Fousek, V., Slanina, F. Mixed corrosion inhibitor for metals (1981), patent DE 2949394 A1 19810611.
The corrosion inhibitor contains an alk. agent 5-30, film-forming C10-25 amine 5-50, and alkanolamide of unsatd. fatty acids 10-40 or imidazoline and its derivs. 5-25, or ester of fatty acids with alcs. 5-25 wt.%. The inhibitor is dild. in a solvent in a 1:(5-50) ratio. The inhibitor is suitable for protection of metal equipment used for recovery, storage, and transportation of natural gas. Typically, 0.2 L inhibitor/1000 m3 gas is injected. Thus, corrosion inhibitor contg. cyclohexylamine 30, octadecylamine [124-30-1], and alkanolamide of unsatd. fatty acids 40% was used as 10% soln. in lab. tests. The corrosion inhibitor efficiency was 93%.
Pelikan, J., Smrz, M., Vosta, J. Surface treatment of an aluminum electrode prior to electrochemical measurements Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1980), D 41, 25-33.
Treatment of the electrode in a bath composed of 80 mL concd. H3PO4, 10 mL concd. HNO3 and of 10 g citric acid for 30 s at 85° followed by pickling in a 5% aq. NaOH for 60 s was found to be the best with respect to constancy of rest potential with time.
Vosta, J., Pelikan, J., Laznicka, P. Study of corrosion inhibition by faradaic impedance Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1980), D 41, 35-41.
At the corrosion potential for Fe in 5% HCl, the sorption of dibenzyl sulfoxide is irreversible, the inhibiting reaction being proceeded by chemisorption. The inhibiting action becomes a reversible reaction at more pos. potentials. Capacitance and resistance becomes higher with decreasing frequency (10 kHz to 300 Hz) in the cathodic part of the polarization curve.
Pelikan, J., Vosta, J., Antos, M. A study of corrosion inhibition of aluminum in an aqueous chloride medium Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1980), D 41, 17-24.
Both chromates and nitrates exhibit inhibition effects only when their concn. is higher than 10-3M. Chromates at these concns. enhance the induction time but they do not affect the potential of repassivation. Nitrates do not affect the induction time. The c.d. on current-time curves did not reach 0.25 mA.cm-2 within 120 min when chromate concn. was >5 × 10-3M, in the case of nitrates concn. >10-2M being necessary for reaching the 0.25 mA.cm-2 c.d. limit but the time course of c.d. is then decreasing. Breakdown potentials detd. by the potentiodynamic method are with increasing concn. of inhibitor shifted to pos. values more than when they are detd. by stationary methods.
Vosta, J. Pelikan, J. Eliasek, J. Corrosion inhibition Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1980), D 41, 83-103.
A review with 119 refs. on the mechanism of corrosion and classification of corrosion inhibitors is given.
Pelikan, J., Vosta, J., Mostecky, J., Smrz, M., Lohnisky, J. Liquid deicer (1980), patent CS 184118 B1 19800715.
Deicing mixts. contain an aq. urea [57-13-6] soln., EtOH [64-17-5], and a selective corrosion inhibitor. Thus, a soln. contg. urea 25, EtOH 25, ZnF2 0.04, Na hexametaphosphate 0.1%, and the balance water inhibits corrosion of hard Mg-Al alloys and is used on airfields. A soln. contg. urea 45, EtOH 5-10, ZnSO4 0.04, Na hexametaphosphate 0.08%, and the balance water inhibits corrosion of steel and is used for road
Pelikan, J., Horejs, J.,; Smrz, M., Vosta, J. Corrosion inhibitor for a neutral aqueous medium (1980), patent CS 183599 B1 19800615.
Mixts. of Na6(PO3)6 (I), benzotriazole (II) [95-14-7], and Na2MoO4 (III) have a synergistic effect manifested by decreased corrosion and deposits. The recommended ratios of I:II:III are 5:0.5:1 for a closed heating system, 5:1:1 for an open cooling charged with distd. water used for heating homes.
Pelikan, J., Vosta, J., Mostecky, J., Smrz, M., Lohnisky, J. Deicing agent for roads (1980), patent CS 183475 B1 19800515.
The agent contains urea 10-99.9, corrosion inhibitor consisting of phosphate or polyphosphate and Zn2+ compds. (e.g. F-, naphthenates, salts of fatty acids, polyphosphates) 0.1-10, and optionally nitrates 12-88% and/or org. compds. having a chemisorption or electrostatic effect (e.g. imidazole derivs). The agent is in the form of granules or aq.-alc. solns. The agent attacks the roads and bridges less than the conventional salt mixts. and is less harmful to the environment. Typically, the granulated mixt. suitable for application at low temps. consists of urea 70, Na hexametaphosphate 0.1, ZnF2 0.05, (NH4)2HPO4 0.05-0.1%, and balance NaNO3.
Pelikan, J., Vosta, J., Smrz, M. Inhibitor of pitting and intercrystal corrosion (1980),patent CS 182094 B1 19800315.
Treating cooling waters contg. Cl- with 10-4-10-2 mol/L of Na hexametaphosphate and with an alkali sulfate to obtain the SO42-/Cl- ratio of 1-3 prevented incrustation by Ca compds. and decreased corrosion. The above combination exhibited a synergistic effect.
Vosta, J., Pelikan, J., Hackerman, N. Study of the character of the inhibition reaction Annali dell'Universita di Ferrara, Sezione 5: Chimica Pura ed Applicata, Supplemento (1980), 7(Vol. 1, Eur. Symp. Corros. Inhibitors, 5th), 255-66.
In this investigation quantum chem. was applied to the study of the character of inhibition of the dissoln. reaction of Fe in aq. acid soln. by using impedance measurements. Results of HMO-LCAO calcns. were correlated with data from the electrochem. investigations of inhibition of this reaction rate by org. compds. Results of this study may also be used in the general evaluation of inhibition corrosion was catalytic processes where the interaction of the compd. with the metal or catalytic bed is involved.
Pelikan, J.,Smrz, M., Vosta, J. Agent inhibiting corrosion of magnesium and its alloys (1980), patent CS 182093 B1 19800315.
Mg alloy systems in at. reactors were protected by treating with solns. contg. 0.02 K2SiF6 and optionally 0.005% ZnSiF6.
Pelikan, J., Smrz, M., Vosta, J. Concrete corrosion caused by deicing agents Stavivo (1979), 57(3), 84-6.
To simulate the action of deicing agents, concrete specimens were cyclically immersed 12 h in water and solns. of NaCl, CaCl2, NH4NO3, EtOH [64-17-5], urea [57-13-6], Na2SO4, and chloride-free(EtOH + urea)-contg. deicing agent AM-75 [57894-57-2]. After ≤50 cycles, concrete wt. losses, pH changes of the deicing solns., and amt. of dissolved Ca, Si, and Al were detd. The best results were obtained with AM-75.
Mostecky, J., Kolihova, D., Sychra, V., Kremanova, B., Talasek, V., Vosta, J., Bajkay, S., Cerny, M. Complex workup of tetrahedrite concentrate(1979), patent CS 177947 B1 19790315.
Mixts. of tetrahedrite and chalcopyrite contg. Sb, Ag, Hg, Zn, and silicates were treated with boiling HNO3 and the solid phase, contg. Hg and Sb, was worked up pyrometallurgically. The liq. phase was treated with Ca(OH)2 and the pptd. metal hydroxides were subjected to pyrometallurgical or electrolytic refining. The filtrate contg. Ca(NO3)3 was used as fertilizer.
Mostecky, J., Vosta, J., Singer, P., Panacek, F. Salt additives for spreading on roadways(1979), patent CS 177216 B1 19770729.
The combination of inorg. and org. corrosion inhibitors had a synergistic effect against corrosion produced by Cl-. Thus, a mixt. of NaCl 85, MgCl 5, Na silicate 7, and aq. emulsion of octadecylamine [124-30-1] 3 parts had a good deicing effect on roads and the silicate component affected the road surface favorably.
Pelikan, J., Vosta, J., Panacek, F., Eliasek, J., Mostecky, J. Corrosion inhibitor (1978), patent CS 174913 B1 19770429.
Mixts. of (NaPO3)6 [10124-56-8] 4-67, KMnO4 0.5-22, and/or KClO3 10-35, and/or optionally Na silicate 16-80 and CaCl2 0.1-3% inhibits the corrosion of steel [12597-69-2] surfaces by road deicing mixts. and cooling salt solns.
Talasek, V., Vosta, J., Eliasek, J., Mostecky, J.,Ocenasek, M., Matejka, Z.Treatment of surface waters and power engineering condensates containing organic cations (1978), patent CS 171820 B1 19761129.
Polluted waters are passed through a mixed bed contg. a macroporous strongly acid cation exchanger (A) and a gel cation exchanger (B). The loose inner structure of the macroporous ion exchanger permits reversible sorption and easy desorption of large org. cations and protects the gels from contact with dissolved org. substances. Macroporous Lewatit S 100X10/50 [68517-53-3] (cross-linked with 10% divinylbenzene) or a combination of Lewatit CNP [56940-15-9] with Zerolit 225 [37206-32-9] are used for A and the gel cation exchanger Lewatit S 100X10 [68517-52-2] for B.
Pelikan, J., Vosta, J., Cozl, V. Corrosion of steel in cooling water treated with peracetic acid Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1977), D 35, 87-98.
The corrosion rate of steel [12790-81-7] was detd. by immersion tests in model cooling water contg. 0.1-2% peracetic acid [79-21-0]. The corrosion rate was 5.2, 13.4, 116.0, and 278.3 g/m2-day in 0, 0.1, 1, and 2% AcOOH, resp. For concns. of 0.1 and 1%, the inhibiting effects of some inorg. compds. were detd. Best results were obtained with K2Cr2O7 and K2CrO4-(NaPO3)6-ZnSO4; the corrosion rate decreased to 3.5-1.2 and 81.7-45.4 g/m2-day in 0.1 and 1% AcOOH, resp. Of the org. inhibitors, fair results were obtained with CS(NH2)2 [62-56-6] (corrosion rate 51.5 g/m/day in 1% acid) and with Resistin K [(lauramidoethyl)pyridinium isooctyl xanthate] [54578-20-0]) which decreased the corrosion rate to 4.5 and 65.4 g/m2-day in 0.1 and 1% AcOOH, resp. Inhibitors were used in concns. of 10-3-10-2M.
Hradil, Z., Riedl, R., Mencl, F., Vosta, J. Inhibitor for acid pickling baths (1977), patent CS 168993 B1 19760629.
The corrosion inhibitor for steel consists of a nitrobenzene-formaldehyde mixt. Thus, steel sheet was immersed in a 3% citric acid soln. at 50°. When the soln. contained 0.3% formaldehyde [50-00-0]-30% nitrobenzene [98-95-3] mixt., the corrosion protection was 99%.
Vosta, J., Pelikan, J., Vanek, F. Study of the behavior of iron in amidosulfonic acid using polarization resistance and polarization curves , Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1977), D 35, 99-112.
Polarization resistance in the dissoln. of Fe in 5% NH2SO3H strongly increases by addn. of dibenzyl sulfoxide and Resistin N (benzylpyridinium isooctyl xanthate). These inhibitors in concn. 10-3M have a good performance at 75°. The inhibitors substantially influenced the cathodic reaction.
Pelikan, J.,Vosta, J., Cozl, V. Pitting corrosion of steel in cooling water Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1977), D 35, 77-85.
Potentiokinetics polarization was used to det. the pitting potential Ep for steel in cooling water at 22 ± 2° and study the effect of inhibitors which produce a shift of Ep toward more pos. values. The lowest concns. used for the individual inhibitors were as follows: Na6P26O18 2 × 10-5, K2CrO4 5 × 10-5, ZnSO4 10-4, Na2MoO4 2 × 10-4, ZnCl2 5 × 10-4, and NaNO2 10-3M and the initial Ep value for the cooling water (-180 mV vs. SCE) was increased by 20 up to 80 mV. At higher concns. Ep continued to increase, the most pronounced effect being that of NaNO2 at concns. 2 × 10-2 and 5 × 10-2 M giving Ep values of 68 and 123 mV, resp. At low concns. of the inhibitor corrosion does not increase but pitting may take place. The concn. level is detd. by the salinity of the cooling water, esp. the content of Cl-, SO4-, NO3-, and HCO3 and the presence of org. compds. and microorganisms is also a factor.
Vosta, J. Measurement of the capacity of an electric double layer by a single pulse technique Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1977), D 35, 113-19.
The single pulse technique was employed to measure the capacitance of the elec. double layer on a Fe electrode in 6N HCl at 25°. The capacitance increases linearly with time. This increase is caused by adsorption of H+, Cl-, and OH- and a change of electrode surface.
Pelikan, J., Vosta, J.,Macura, J. A study on the corrosion of aluminum and duralumin in an inhibited sodium chloride solution Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1977), D 35, 61-75.
Potentiodynamic polarization curves were used to study the effects of inhibitors on the pitting corrosion of Al and Duralumin in satd. and dil. aq. NaCl (0.01, 0.1, 1, 3, and 5%). The possible inhibitors were: K2CrO4, K2Cr2O7, (NaPO3)6, NaH2PO4, Na2HPO4, and hexamethylenetetramine and were used in a 0.01M concn. The measurements were carried out using std. app. and the voltage change was 4.8 V/h. Low concns. of the inhibitors actually increased the pitting corrosion.
Vosta, J.; Havel, J. Spectrophotometric study of the complexation of praseodymium(III) with 4-(2-thiazolylazo)resorcinol and 1-(2-thiazolylazo)-2-naphthol-3,6-disulfonic acid Collection of Czechoslovak Chemical Communications (1977), 42(10), 2871-89.
Dissocn. consts., complexation consts., complex compns., and molar extinction coeffs. were calcd. from spectrophotometric data of 4-(2-thiazolylazo)resorcinol (I), 1-(2-thiazolylazo)-2-naphthol-3,6-disulfonic acid (II), and their complexes with Pr(III) in 30% aq. EtOH at pH 0-8 and various Pr(III):I or II ratios. I and II form 1:1 complexes with excess Pr(III). Excess I (LH2) forms a 1:1 complex with Pr(III) at pH 2-6.5 which is deprotonated at higher pH and an almost insol. 1:2 complex PrL(LH).6H2O. Excess II (LH3) forms a 1:1 complex with Pr(III) and at higher II concns. also PrL(LH)2+.
Pelikan, Josef; Vosta, J.; Smrz, M. Inhibition of unstabilized steel 18Cr8Ni in cooling water at 50°C Werkstoffe und Korrosion (1977), 28(2), 85-7.
The most efficient corrosion inhibitor was evaluated for stainless steel 18-8 [12671-80-6] simulated cooling-water systems with added Ca2+, Cl- and SO42- by detg. pitting-corrosion potential by potentiodynamic anodic polarization at 50° and c.d. 0.5 mA/g. Inhibitors (Na2SO4, Na2MoO4·2H2O, K2CrO4, NaPO3, NaNO2, and Na3PO4.12H2O) were used in 10-4-10-2M concns.
Sujan, J., Mostecky, J., Talasek, V., Vosta, J., Bartusek, Z. Activator of gramophone disc surface (1976), patent CS 162910 B1 19750715.
An agent for activation of a record surface, which removes grease and dust, repels dust, and reduces wear of disk and stylus is prepd. Such a lubricant has the following compn.: iso-PrOH [67-63-0] 35, 1,1,1-trichloroethane [71-55-6] 55, 1,4-dioxane [123-91-1] 3, C10-20 paraffins 2.99, silicone oil 4.0, fragrance 0.01, stearamidopropyldimethylhydroxyethylammonium nitrate [2764-13-8] 0.5, and perfluorinated C10-15 n-alkanes 4.0 wt. %.
Sujan, J., Mostecky, J., Talasek, V., Vosta, J. Activator of gramophone disc surface (1976), patent CS 162909 B1 19750715.
An agent for activation of a record surface, which removes grease, dust, and elec. charge, and reduces wear of disk and stylus, is prepd. Such a lubricant has the following compn.: iso-PrOH [67-63-0] 63.0, 1,1,1-trichloroethane [71-55-6] 30.0, 1,4-dioxane [123-91-1] 2.0, C10-20 paraffins 1.0, silicone elastomers 3.0, and fragrance 0.1 wt.%.
Vosta, J., Eliasek, J. Knizek, P. A quantum-chemical study of the corrosion inhibition of iron by means of aniline derivatives in hydrochloric acid Corrosion (Houston, TX, United States) (1976), 32(5), 183-7.
To det. the mechanism of corrosion inhibition by org. materials, the electron structure of a set of org. compds. is studied and correlated with their electrochem. corrosion measurements. The inhibition of corrosion of Fe in 5% HCl by p-substituted anilines with respect to quantum chem. is discussed. Fe2+ ions originating from the dissoln. of Fe form complex Fe(Cl)64- ions on the metal surface at anodic centers. The protonized aniline mols. are then electrostatically bonded to these complex ions. Thus, a potential barrier is formed which prevents the corrosive medium from reacting with the metal surface.
Mostecky, J., Vosta, J., Talasek, V., Recovery of mercury from waste gases (1975), patent CS 160448 B1 19750328.
Waste gases from the roasting of ores, contg. Hg drops of size 10-5-10-1 mm, are passed through a column charged with finely grained active C or scrubbed with an aq. suspension of crushed coke. Quant. recovery of Hg by roasting the adsorbates is facilitated by the presence of C which creates favorable redn. atm. Alternatively, waste gas contg. Hg is fed into a column packed with Al rods activated with an aq. ZnCl2 soln. and Hg quant. coverted to Al amalgam.
Mostecky, J., Voldrich, K., Vosta, J., Talasek, V., Singer, P. Bactericidal agent with corrosion inhibiting effect (1975), patent CS 157901 B1 19741015.
Octadecylamine (I) [124-30-1] controls bacteria and inhibits corrosion by film formation. Thus, 10 mg I/l., in a poly(ethylene glycol) emulsion contg. 0.1-1 mg NaHCO3 [144-55-8]/l. and 100 mg N2H4 [302-01-2]/l., controlled bacteria in, and inhibited corrosion by, nuclear power plant effluents contg. HNO3 and H2C2O4.
Vosta, J.; Havel, J. Liquid-liquid ion selective electrode responsive to univalent anions Scripta Facultatis Scientiarum Naturalium Universitatis Purkynianae Brunensis (1973), 3(9), 109-15.
A liq.-liq. ion-selective electrode has a membrane consisting of a porous Teflon disk which was soaked in a soln. of tetra-n-hexylammonium iodide in lauryl alc. and was placed inside the plastic electrode body. A Ag/AgI ref. electrode immersed in a soln. of 0-1M KCl and 0.1M NaClO4 is placed inside the electrode. The electrode showed a Nernstian response to I- and ClO4- at 1-10-3.5M. MnO4- ≥10-2M poisoned the electrode. The electrode showed no response to polyvalent anions. The selectivity of the electrode to I- decreased with decreasing I- concn.
Vosta, J.; Havel, J. Potentiometric determination of perchlorate and quaternary onium salts with the use of an ion selective electrode, Scripta Facultatis Scientiarum Naturalium Universitatis Purkynianae Brunensis (1973), 3(9), 99-107.
An ion-selective electrode membrane is prepd. by polycondensation of 1.7 g Bakelite A (prepd. according to T. N. Dobbelstein and H. Diehl, 1969), 0.6 g Ni(ClO4)2.6H2O, 0.3 ml ethylene glycol, and 2 ml 37% aq. H2CO. When the H2CO used contained free H2CO2, 0.2 ml 25% NH4OH was added. The response of the electrode to ClO4- was linear for 10-3.5-10-1M at pH 2.13 ± 0.03. The electrode was used for potentiometric titrn. of cetylpyridinium sulfate and butyltriphenylposphonium sulfate with NaClO4 and for the detn. of soly. products of BuPh3PClO4, cetylpyridinium perchlorate, Ph4PClO4, tetrahexylammonium perchlorate, Bu4NClO4, and Pr4NClO4. The electrode was used also for the detn. of cetylpyridinium bromide (I) and BuPh3PBr by titrn. with AgClO4. The error was ≤±1% for the detn. of 0.02355M I and 0.02555M BuPh3PBr. The results agreed well with the results obtained by using Ag electrode and with the results obtained by gravimetric detn. by using phosphotungstic acid as pptg. agent. NO3- and other univalent anions interfered. The electrode can be used for direct potentiometric detn. of ClO4- with suitable pptg. agent.
Mostecky, J.,Talasek, V., Vosta, J., Voldrich, K., Singer, P. Anticorrosion protection of cooling circuits of nuclear reactors (1974), patent CS 156002 B1 19740624.
Corrosion by H2O, D2O, and CO2 is reduced by addn. of octadecylamine, piperidine and cyclohexylamine which produce the desired mild alky. since the Na+ causes a high induced activity. Alkylarylpolyglycol ethers have emulsifying and inhibition effects and H3PO4 [7664-38-2] is a passivation component.
Vosta, J.; Pelikan, J.; Smrz, M. Investigation of corrosion inhibitors for iron in hydrofluoric acid Werkstoffe und Korrosion (1974), 25(10), 750-3.
Studies on the inhibition of the corrosion of Fe in 0.5-9.5% HF by gravimetry and measurements of the polarization resistance and potentiodynamic polarization revealed that dibenzyl sulfoxide and laurylpyridinium isooctylxanthate with thiourea are efficient corrosion inhibitors. Thiourea, pyridinium xanthate (Resistin K), urotropine, diphenylthiourea, diphenylthiocarbazide, and diphenylguanidine also have good inhibiting properties. The effect was interpreted generally in terms of the availability of free electron pairs.
Eliasek, J., Vosta, J., Talasek, V., Mostecky, J. Agent for protection of hot water lines (1974), patent CS 153733 B1 19740329.
A 1:5 mixt. of octadecylamine and Na polyacrylate or polymethacrylate of mol. wt. 10,000-25,000 was added to distd. water to form a colloid suspension and fed into the pipes. The agent prevented incrustations and corrosion in amts. of 6 g/ton water.
Vosta, J., Talasek, V., Mostecky, J., Eliasek, J., Panacek, F., Singer, P. Mixed corrosion inhibitor (1973), patent CS 151601 B1 19731119.
The mixed corrosion inhibitor consists of evapn. inhibitors (e.g., piperdine, nitrite, or cyclohexylamine nitrite), bivalent anions (e.g. chromates, tungstates) combined with NaNO2, silicates, phosphates, urea and its derivs., hexamethylenetetramine, and optionally volatile bases (e.g. piperidine, cyclohexylamine, NH4OH) and org. peroxides (e.g., perbenzoic acid and/or its salts, dibenzoyl peroxide). Thus, metal sheet was protected by a passivation inhibitor contg. piperidine nitrite 0.65, cyclohexylamine nitrite 1.45, Zn hexametaphosphate 0.8, and piperidine 0.01 g/l.
Sejnoha, R., Talasek, V., Vosta, J., Eliasek, J., Vcelak, L. Cleaning of sewage drains (1973), patent CS 149103 B1 19730524.
Sewage drains were cleaned by circulation of 5% aq. HCl or H2SO4 contg. 0.2-0.3% dibenzyl sulfoxide [621-08-9] 15-20 min at 20-75.deg., followed by rinsing with water and treating with 5% Na nitrite [7632-00-0].
Eliasek, J., Mostecky, J., Vosta, J., Talasek, V., Singer, P., Voldrich, K. Corrosion inhibitor and passivator for metals (1973) patent CS 149254 B1 19730524.
Octadecylaminophosphate is esp. effective in steam lines owing to the double effect of Na phosphate, liberated by addn. of a calcd. amt. of NaOH, and of octadecylamine which volatilizes in steam and protects the condensor tubes from corrosion. Other useful applications are in automotive cooling systems and in cooling of nuclear reactors contg. D2O and CO2.
Mostecky, J., Nemcova, J., Vosta, J., Singer, P.,Panacek, F., Sverepa, F. Additive ice-thawing mixtures for roads (1973), patent CS 148729 B1 19730524.
Cyclic polymers of the type (XPO3)n provide (in combination with Zn and Cd salts) efficient inhibition of metal corrosion by mixts. contg. NaCl. Upon contact with thawing snow or ice, (XPO3)n is hydrolyzed with opening of the polymer polyphosphate ring. The resulting uncoiled chain reacts through its exposed OH groups with the metal surface and the Zn and/or Cd component present to produce (on the protected surface) a compact layer with a high ohmic resistance which prevents contact of the surface with the atm. and inhibits surface corrosion, while the Zn ions inhibit (in combination with polyphosphate) slot corrosion. Recommended compn. of the mixt. is, e.g., NaCl 90, Na hexametaphosphate 6.6, and ZnSO4 3.4 parts by wt. The corrosion preventing effects can be increased further by addn. of org. compds. with a chemisorption and electrostatic effect, viz. guanidine, urea, PhCN, or BzONa.
By Mostecky, J., Vosta, J., Panacek, F., Singer, P., Nemcova, J., Voldrich, K. Additive for ice-thawing mixtures for road (1973), patent CS 148730 B1 19730524.
The addn. of Al and/or Mg salts to the usual ice-thawing mixts. decreased (in combination with the other corrosion inhibiting components) the extent of crevice corrosion in exposed metal surfaces. The compn. is given of 8 mixts. contg. NaCl 90, Al2(SO4)3 or MgSO4 2.5-6, Na silicate 1.5-3, and octadecylamine, urotropine, mercaptobenzotriazole, 2-naphthalenethiol, or thioglycol <3%. The prepns. showed a 91-3% inhibitory effect in comparison with 65% obtained with Carguard.
Mostecky, J., Vosta, J., Panacek, F.,Singer, P., Nemcova, J., Voldrich, K. Mixed inhibitor of chloride corrosion(1973), patent CS 147451 19730215.
Al(III) and/or Mg(II) salts are combined with org. compds. with a chemisorption and/or electrostatic inhibition effect for use as additives in refrigerator brine solns. and ice-creep removing mixts. The combinations contain Al2(SO4)3, MgCl2, MgSO4, Na hexametaphosphate, C12-18 fatty acids, octadecylamine, urotropine, mercaptobenzothiazole, phenylthiourea, 2-napthalenethiol, tannin, thioglycol, etc.
Mostecky, J., Nemcova, J., Vosta, J., Singer, P., Panacek, F., Sverepa, O. Mixed inhibitor of chloride corrosion (1973), patent CS 147355 19730215.
Na hexametaphosphate (I) affords, in combination with Zn(II) or Cd(II) salts, an efficient protection of steel surfaces from ice-creep thawing mixts. contg. NaCl. Upon contact with thawing ice, the cyclic I polymer is hydrolyzed with H2O yielding an open polymer polyphosphate chain which reacts through its OH groups with the Fe surface and Zn2+ or Cd2+ to give a compact protective coating with a high ohmic resistance. The coating inhibits surface corrosion, while the polyphosphate-metal complex inhibits crack corrosion. The protective effect is further enhanced by addn. of org. compds. with chemisorption and/or electrostatic inhibition effect (guanidine, urea, PhCN, BzONa).
Mostecky, J., Vosta, J., Talasek, V., Eliasek, J., Matejka, Z. Selective recovery of nonferrous metals from industrial waste waters (1972), patent CS 145167 19720915.
Approx. 80-5% Mn, Cu, and Zn were recovered from washing and recycled waters of ore-processing plants by passing through chelation ion exchangers contg. iminodiacetate of carboxylic group in Na cycle.
Vosta, J., Eliasek, J., Mostecky, J. Inhibitors of metal corrosion in acid solutions (1972), CS 144135 19720101.
Mesoionic compds. with dipole moments, >6 D have a high corrosion-inhibiting effect owing to their amphoteric properties. This makes preliminary orientation of the inhibitor mols. on the metal surface unnecessary and speeds up the inhibition process. Solns. of 0.02% nitron in 5% HCl and 0.03% sydnone in 15% H2SO4 have a good corrosion inhibiting effect.
Vosta, J.; Eliasek, J. Study of corrosion inhibition from the quantum chemistry aspect, Edited by Hamner, Norman E., Proc. Int. Congr. Metal. Corros., 4th (1972), 598-601.
Quantum chem. values for the pyridine N-oxides of parasubstituted N(CH3)2, SH, CN, Me, and NO2 were correlated with the inhibition efficiency detd. by polarization curves on an Armco Fe electrode in 5% HCl at 25°. Results showed the inhibition efficiency depends on the energy of the HOMO (highest occupied MO) and LFMO (lowest free MO).
Vosta, J.; Eliasek, J. Quantum chemical evaluation of nitron as a corrosion inhibitor Werkstoffe und Korrosion (1972), 23(6), 487-9.
The corrosion inhibition by nitron with mesoionic structure was evaluated by using the LCAO method and studied exptl. for Fe (99.999% pure) in 5% HCl. The inhibiting efficiency increases with increasing energy of the highest occupied MO due to the decrease of the ionization potential. Certain positions in the nitron mol. characterized by increased electron d. can thus contribute with their own electrons to the bond formation between inhibitor and metal
Talasek, V., Mostecky, J.,Vosta, J., Eliasek, J., Matejka, Z. Separation of nonferrous metals from calcium-containing solutions using weak acid or chelating ion exchangers Chemický Průmysl (1972), 22(2), 69-71.
Mn2+ and Cu2+ can be sepd. from Ca2+-contg. solns. by the carboxylic cation exchanger Amberlite IRC-50 or by the chelating ion exchanger Dowex A-1 at high sp. loads. The latter resin is advantageously used for systems with small differences in selectivities since the stability of the nonferrous-metals chelates generally differs from that of alk. earths. The carboxylic resin is applicable for systems characterized by different selectivities of their components. With respect to the resp. vol. capacity, the carboxylic resin is more suitable for adsorbing Cu and the chelating resin for the sepn. of Mn. The degree of purity and concn. of Mn and Cu in the eluates from both the tested resins is high enough to justify their further treatment.
Matejka, Z., Talasek, V., Vosta, J., Mostecky, J.,Eliasek, J., Singer, P. Regeneration of mixed-bed ion exchangers (1971), patent CS 140562 19710315.
Mixed beds, contg. an acid or polyfunctional cation exchanger in H+, Na+, or mixed cycle (Na+, Ca2+, Fe3+), and a basic or polyfunctional anion exchanger in OH-, Cl-, or mixed cycle (Cl-, SO42-, PO43-), are regenerated with aq. 1-20% piperidine or cyclohexyl amine, which converts the cation exchanger into piperidinium or cyclohexylammonium cycle, and the anion exchanger into OH- cycle in a single run without sepg. the resins. The regeneration process is esp. useful for the treatment of industrial condensates and cooling waters.
Vosta, J.,Talasek, V., Eliasek, J., Rysan, J. Use of spent sulfuric acid from titanium white production as a pickling agent in metallurgy Chemický Průmysl (1971), 21(10), 485-8.
Fe and Ti compds. contg. dil. H2SO4, as produced in the manuf. of TiO2, can be utilized as a steel pickling agent. The kinetics of the pickling process was studied with both spent and pure acid used for treating homogenized scale samples and scaled or descaled steel plates. The kinetic data obtained by chem. analyses of the solns. and by weighing the plates compared well with those based on the potentiometric detn. of corrosion currents. In spent acid solns. the process of pickling always proceeded more slowly than in pure H2SO4 of the same concn. due to a higher ionic strength in the former; consequently, the most marked differences in the reaction rates were obsd. at the initial stage of pickling. To attain a pickling efficiency equal to that of 12% pure H2SO4, a spent soln. contg. 15% H2SO4 (65°) must be used.
Vosta, J.; Eliasek, J. Corrosion inhibition from the aspect of quantum chemistry Corrosion Science (1971), 11(4), 223-9.
Relative to the selection and quant. evaluation of corrosion inhibitors a study was made of quantum-chem. values and inhibition efficiency by using homologous series of pyridine N-oxides with various substituents in the γ-position with quantum-chem. values calcd. by the LCAO method. Substances studied included those with Me2N, HS, CN, Me, and NO2 substituents. Polarization curves were measured at 25° in 5% HCl. Inhibition efficiency depended mostly upon the energy of the highest occupied MO (HOMO), k(1), which is a theoretical analog to the ionization potential of a substance, and the energy of the lowest free MO (LFMO), k(-1), which illustrates the electron affinity of the mol. Inhibition efficiency increased with increased energy of the HOMO, i.e. with the decrease in the ionization potential so that the mol. acts as an electron donor when blocking the corrosion reaction. Other values obtained by quantum-chem. calcn. (e.g. electron d., free valences, bond orders) verified these principal concepts. Inhibitors with higher efficiency have even higher electron d. in the presumed inhibition centers which participate by their own electrons when forming a chem. bond with a metal; electrophilic substitution may take place in a reaction between metal and inhibitor. Free valence values do not exclude the possibility of a radical reaction. The most active site of the compds. assessed was the O in the N-O and S-O groups due to its min. at. localization energy and high values of electrophilic and radical superdelocalizability on the O atom.
Vosta, J., Eliasek, J.,Janda, M. New corrosion inhibitors Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1970), D 20, 23-33.
The evaluation of boiler steel corrosion inhibitors by means of polarization curves and polarization resistance was studied. Nitrone and some thiophene derivs. are very good corrosion inhibitors in a HCl medium. Esp. nitrone which belongs among the mesoionic group of compds., proved to be the most efficient of them. 8,9-Dihydrothionaphthene dioxide was chosen because of its resemblance to dibenzyl sulfoxide in regard to S-O groups. 2-Aminopyridine was subjected to measurements in order to obtain some primary information on the behavior of this substance as corrosion inhibitor in a HCl medium.
Vosta, J., Talasek, V., Ocenasek, M., Eliasek, J., Volak, J. Use of piperidine as a volatile alkalization agent Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1969), 18, 15-28.
Piperidine was used as a volatile alkalization agent and corrosion inhibitor in a high-pressure steam-water circuit. Piperidine is of sufficiently basic character, which makes it possible to decrease P2O5 content in boiler water to the 3 mg/l. level. It achieved a 70-80% decrease of Fe level in the system, and is inactive with respect to Cu. In the H-form of strongly acid cation exchangers piperidine is quant. sorbed as piperidinium cation and regeneration of exchanger is quite possible.
Mostecky, J., Eliasek, J., Singer, P., Talasek, V., Vosta, J. Protective agent for steam ducts in power engineering plants (1969), patent CS 133224 19690715.
Mixts. of 1 part C18H37NH2 (I) and 0.01-1 part emulsifier are added at a rate 0.01-10 g agent/ton steam or 10-1000 g agent/ton feed water after the demineralization process. Alkane- and arenesulfonyl chlorides, sulfosuccinates, and condensation products of fatty acids with ethylene oxide are suitable emulsifiers. I forms in the ducts a protective lining which prevents the effect of corrosive media and blocks starting corrosion reactions on microcathodes and anodes.
Talasek, V., Vosta, J., Matejka, Z., Eliasek, J., Mostecky, J., Singer, P. Treatment of condensate in power engineering installations (1969), patent CS 133232 19690715.
Cation-exchanger beds in the piperidinium from have a very low selectivity coeff. for the piperidinium cation when the cation exchanger is in a neutral medium. In combination with simultaneous alkalization of the feed-water with piperidine, there is provided quant. trapping of all metal ions that have gotten into the condensate by leakage or corrosion.
Vosta, J., Talasek, V., Eliasek, J. Inhibitor of atmospheric corrosion (1969), patent CS 133138 19690715.
Combinations of 1 part piperidine nitrite (I) and 0.5-1 part volatile alk. agent show a synergistic effect. The volatile compd. (NH3, cyclohexylamine, N2H4, piperidine, morpholine) blocks the initial corrosion process and initiates the evapn. of I, which affords a long-lasting protection. The combination in concns. of 0.5-2 g/m2 Fe or Cu surface gives 80-100% protection for 100-200 days at 80% relative humidity.
Mostecky, J., Eliasek, J., Talasek, V.,Vota, J., Singer, P. Emulsion mixture for protection of steam-water circuits of energy installations against corrosive attack and process for its application (1969),patent DE 1816905 19690731.
Corrosion in steam power and heating plants is prevented by addn. to the process water of 0.01 to 10 g./ton active ingredient of an emulsion consisting of 1 part by wt. higher aliphatic amine (primary, secondary, or tertiary) and 0.01 to 1.0 part by wt. emulsifier. Preferred amines are octadecylamine, laurylamine, hexadecylamine, and dioctadecylamine. Preferred emulsifiers are ethoxidized fatty acid, alkylpolyglycol ether, saccharose monostearate and polyethylene glycol 1500. For the prevention of crevice corrosion 0.01 part by wt. ZnSO4 and 0.01 part by wt. P2O5 equiv. can be added. Greater effectiveness over previous amine systems is claimed.
Karas, F., Vošta, J.,Talášek, V. Protection of steam lines of power plants from corrosion (1968), patent CS 127179 19680415.
A mixt. of 3 g. octadecylamine and 100 ml. distd. water is emulsified at 60-70° with a suitable agent of mol. wt. 420-1200 and fed into the pressure-free part of a steam line. The film prevents direct corrosion and blocks initial corrosion reaction on microcathodes and microanodes.
Vosta, J., Talasek, V. Volatile alkalizing agent in steam lines of power plants (1967), patent CS 124203 19670915.
Piperidine, fed in an amt. 5 g./ton steam and concn. 2 mg./l., decreased the Fe and Cu content in the condensate by 60-80% and 30%, resp. The initial concns. were 50 μg. Fe and 20 μg. Cu/l. condensate.
Talasek, V., Vosta, J., Eliasek, J. Coulometric determination of ion concentrations of piperidine in aqueou solution in the presence of ammonia Fresenius' Zeitschrift fuer Analytische Chemie (1967), 230(1), 29-33.
A method for the detn. of low concn. of piperidine in aq. solns. and in the presence of NH3 is described. To a 5-70 ml. sample was added M NaBr soln. and a soln. buffered at pH 8 contg. 1 part 0.33M KH2PO4 and 19 parts 0.33M Na2HPO4, so that the final minimal concns. were 0.1M Br- and 0.02M buffer. The Br- reacts quant. with the piperidine to substitute H on N. The excess Br- is then coulometrically titrated to det. indirectly the amt. of piperidine present in the sample. In the presence of NH3, the sum of piperidine and NH3 is detd. coulometrically after similar treatment with Br-, and NH3 is then sep. detd. according to Nessler's photometric method. The piperidine content results from the difference. Piperidine concns. 3 detn.
Pecka, K., Vosta, J.,; Mostecky, J. Possibilities of using sulfolane for removal of sulfurous compounds from lighter petroleum fractions Sbornik Vysoke Skoly Chemicko-Technologicke v Praze, D: Technologie Paliv (1966), 11, 83-96. | Language: English, Database: CAPLUS
Sulfolane (2,3,4,5-tetrahydro-1,1-dioxythiophene) (I) was prepd. by catalytic hydrogenation of sulfolene in MeOH. The hydrogenation was carried out in a rotating autoclave at 100° and with an initial charging pressure of 100 atm. H and was catalyzed by Raney Ni. Sulfolene was prepd. by addn. of SO2 to butadiene with a yield of 93%. The reaction was carried out in an autoclave at 100°. After rectification, I b15 150-1° and d404 1.2533. The gasoline fraction b. 80-150° was distd. from the primary gasoline fraction from Romashkhino petroleum. Extn. expts. with the gasoline fraction showed that the distribution coeffs. of sulforous compds. contained in gasoline between the hydrocarbon phase and I are low. The extn. capability of I for the removal of sulfurous compds. from petroleum fractions was therefore also low. The greatest redn. in the overall S content, ∼50%, was attained by 8-stage countercurrent extn., but the solvent consumption was high and the raffinate yield low. The expt. with 5-stage countercurrent extn. showed that when utilizing the solvent economically and maintaining high yields of raffinate, I has an extremely low desulfurizing effect. Considering that I is a polar extn. agent, the ability of I to ext. the most polar type of S compd.-the mercaptan-from a hydrocarbon medium was studied. The expts. were carried out with model mixts.; the hydrocarbon medium was represented by n-C7H16 and the sulfurous component by BuSH. The phase equil. was measured in the 3 component system n-C7H16-I-BuSH for the whole range of component concn. The distribution coeffs. of S compds. between I and the hydrocarbon phase were low and aromatic hydrocarbons were extd. together with the S compds. I is a solvent of small efficiency for the given purpose and small selectivity for general application.
Vosta, J., Talasek, V., Ocenasek, M., Eliasek, J., Dluhos, J. Piperidine, a new volatile alkalizing agent Mitteilungen der Vereinigung der Grosskesselbesitzer (1967), No. 106, 39-41.
Piperidine is effective in concns. of 2 mg./l. in the alkali treatment and softening of boiler water and its use enables the phosphate concn. to be lowered to 3 mg. of P2O5/l. It also protects the boiler against corrosion.