Hydrochloric acid, solution inhibited

N— compounds used as acid inhibitors include heterocyclic bases, such as pyridine, quinoline and various amines. Carassiti describes the inhibitive action of decylamine and quinoline, as well as phenylthiourea and dibenzyl-sulphoxides for the protection of stainless steels in hydrochloric acid pickling. Hudson e/a/. refer to coal tar base fractions for inhibition in sulphuric and hydrochloric acid solutions. Good results are reported with 0-25 vol. Vo of distilled quinoline bases with addition of 0 05m sodium chloride in 4n sulphuric acid at 93°C. The sodium chloride is acting synergistically, e.g. 0-05m NaCl raises the percentage inhibition given by 0-1% quinoline in 2n H2SO4 from 43 to 79%. Similarly, potassium iodide improves the action of phenylthiourea . 

A two-component plugging material [1763] consists of an aqueous suspension of bentonite clay powder (20% to 25%), ground chalk (7% to 8%), sulfanol (0.10% to 0.15%), and carboxymethylcellulose (1.0% to 1.5%) as the first component. This solution is pumped into the formation. A gel is formed if diluted hydrochloric acid is pumped down and mixes with the first component. The hydrochloric acid is inhibited with a mixture of alkyl-polybenzyl pyridinium chloride and urotropin. 

G. Trabanelli, F. Zucchi, and G. Brunoro. Inhibition of corrosion resistant alloys in hot hydrochloric acid solutions. Werkstoffe Korrosion, 39(12) 589-594, December 1988. 

The presence of alkali and alkaline earth chlorides may also hinder precipitation of the sulphide thus, from a 0001 molar solution of lead chloride in water at 20° C., precipitation is completely inhibited by hydrogen chloride alone if in a concentration of 1-riV, and by decreasing concentrations of the acid in the presence of increasing quantities of calcium, ammonium or potassium chloride. Cadmium sulphide, precipitated from hydrochloric acid solution, contains adsorbed chlorine,1 the amount depending on the conditions of the precipitation the precipitation is incomplete at 80° C. 

Dilute solutions of sulphurous acid decompose more quickly and completely than concentrated solutions, while in presence of a strong acid the decomposition is inhibited, being completely suppressed in twice-normal hydrochloric acid solution. 

NOTE Attempts to use hydrochloric acid, whether inhibited or otherwise, to clean heavily scaled coils, located in galvanized evaporative condensers, almost always leads to serious damage to the fabric of the system and is therefore definitely not recommended. It may be possible to use an acetic acid solution, as normally there is only a limited attack on the galvanized surface with this material. 

Two-thirds of the material can be converted without drying into 5 and the other third used for preparation of a crystalline sample. Dissolve the third reserved for crystallization (moist or dry) in enough hot acetic acid to bring about solution, add a solution of a small crystal of tin(II) chloride in a few drops of dilute hydrochloric acid to inhibit oxidation, and dilute gradually with 5-6 volumes of water at the boiling point. Crystallization may be slow, and cooling and scratching may be necessary. The pure diacetate forms colorless prisms, mp 224°C, dec. 

BDA [Dow]. TM for inhibited hydrochloric acid solution containing surfactants. 

The importance of this problem is underlined by the data in Table 4 concerning the behaviour of ARMCO iron in 1 N HCl solutions inhibited with the commercial product Borg P16 at a temperature of 75 °C. Borg P16 is a specific commercial inhibitor of the corrosion of iron and carbon steels in hydrochloric acid solutions and is a derivative of the commercial product Rodine 213. This inhibitor is used both for the acid cleaning of steam generators and for pickling baths. 

Titanium (III) chloride may be prepared by cathodic reduction of TiCU in a hydrochloric acid solution if the concentration of TiCls in the solution is sufficiently high, the hexahydrate precipitates on saturation with HCl. The crystallization is apparently inhibited by the presence of tetravalent titanium, and total reduction of the solution is therefore necessary. 

This last effect may be an indication of adsorption of a small impurity in the electrolyte. The inhibited corrosion rates decrease with time and become essentially constant after about two hours. These slopes are not dependent on scan rate or on corrosion rate. The most interesting effect is observed when the inhibited hydrochloric acid solution is aerated the anodic Tafel slope increases while the cathodic Tafel slope decreases dramatically. As would have been expected from the resistance probe measurement the corrosion rate in the aerated inhibitor solution increases. 

N. Ohno, N. Hiroshi, K. Aramaki, Electrochemical and spectroscopic smdies on inhibition mechanism ofbenzyl thiocyanate for iron corrosion in 1 N perchloric and hydrochloric acid solutions, Corros. Sci. 36 (1994) 583-591. 

O.K. Abiola, N.C. Oforka, S.S. Angaye, TO. Braide (2005). Inhibition of corrosion of mild steel in hydrochloric acid solution. Journal of Corrosion Science and Technology 2, p. 116. 

A.K. Satapathy, G. Gunasekaran, S.C. Sahoo, K. Amit, P.V. Rodrigues (2009). Corrosion inhibition by Justicia gendarussa plant extract in hydrochloric acid solution. Corrosion Science 51(12), pp. 2848-2856. 

J.C. da Rocha, J.A. da Cunha Ponciano Gomes, E. D Eha (2010). Corrosion inhibition of carbon steel in hydrochloric acid solution by fruit peel aqueous extract. Corrosion Science 52(7), pp. 2341-2348. 

S. Fuhua, W. Xiutong, Y. Jianqiang, H. Baorong, Corrosion Inhibition by Polyaniline Copolymer of Mild Steel in Hydrochloric Acid Solution. Anti-Corros. Methods Mater. 2011,58,111-115. 

Khaled, K.F., Experimental and theoretical study for corrosion inhibition of mild steel in hydrochloric acid solution by some new hydrazine carbodithioic acid derivatives. Applied Surface Science, 2006. 252(12) p. 4120- 128. 

Behpour, M., S.M. Ghoreishi, N. Soltani, M. Salavati-Niasari, M. Hamadanian, and A. GandomL Electrochemical and theoretical investigation on the corrosion inhibition of mild steel by thiosalicylaldehyde derivatives in hydrochloric acid solution. Corrosion Science, 2008. 50(8) p. 2172-2181. 

Mu GN, Zhao TP (2004) Synergistic effect on corrosion inhibition by cerium (IV) ion and sodium molybdate for cold rolled steel in hydrochloric acid solution Acta Chimica Sinica 62,24, 2386-2390. 

The dissolution of copper and of brasses in acid solutions has been studied by several authors". Various substances have inhibiting effects on the rate of attack of copper or brasses in nitric acid" and in hydrochloric acid". ... 

Direct measurements on metals such as iron, nickel and stainless steel have shown that adsorption occurs from acid solutions of inhibitors such as iodide ions, carbon monoxide and organic compounds such as amines , thioureas , sulphoxides , sulphidesand mer-captans. These studies have shown that the efficiency of inhibition (expressed as the relative reduction in corrosion rate) can be qualitatively related to the amount of adsorbed inhibitor on the metal surface. However, no detailed quantitative correlation has yet been achieved between these parameters. There is some evidence that adsorption of inhibitor species at low surface coverage d (for complete surface coverage 0=1) may be more effective in producing inhibition than adsorption at high surface coverage. In particular, the adsorption of polyvinyl pyridine on iron in hydrochloric acid at 0 < 0 -1 monolayer has been found to produce an 80% reduction in corrosion rate . 

Discussion. The turbidity of a dilute barium sulphate suspension is difficult to reproduce it is therefore essential to adhere rigidly to the experimental procedure detailed below. The velocity of the precipitation, as well as the concentration of the reactants, must be controlled by adding (after all the other components are present) pure solid barium chloride of definite grain size. The rate of solution of the barium chloride controls the velocity of the reaction. Sodium chloride and hydrochloric acid are added before the precipitation in order to inhibit the growth of microcrystals of barium sulphate the optimum pH is maintained and minimises the effect of variable amounts of other electrolytes present in the sample upon the size of the suspended barium sulphate particles. A glycerol-ethanol solution helps to stabilise the turbidity. The reaction vessel is shaken gently in order to obtain a uniform particle size each vessel should be shaken at the same rate and the same number of times. The unknown must be treated exactly like the standard solution. The interval between the time of precipitation and measurement must be kept constant. 

Offline cleaning can, and should, be entirely successful, with the simplest methods requiring, say, a 10 or 15% inhibited hydrochloric (muriatic) acid solution that is allowed to soak for some hours before neutralization, flushing, and refilling. Where the waterside deposit analysis reveals complex scales, however, it may be necessary to employ several different cleaning solvents. These solvents are added in a multistep process. 

R. N. Diyashev, F. M. Sattarova, K. G. Mazitov, V. M. Khusainov, F. N. Mannanov, I. R. Diyashev, and V. A. Burtov. Extraction of oil from lens-shaped deposits—involves cyclic and portion-wise pumping-in of solutions of potassium carbonate and inhibited hydrochloric acid. Patent RU 2065942-C, 1996. 

Acids were an early exception to the no water rule. It was recognized that aqueous solutions of acids would inhibit swelling of clays and shales as well as dissolve any acid-soluble minerals contained in a formation. By 1933 commercial well stimulation with hydrochloric acid was of great interest. A whole separate methodology and treatment chemistry has since evolved around acidizing and fracture acidizing(54). Water emulsions, mainly emulsified acids, and gelled acids thickened with polymeric additives were applied early in the history of well treatment. 

One reagent is a 0.5% aqueous solution of 3-methylbenzothiazolin-2-one hydrazone hydrochloride, and the other is a 0.25% aqueous solution of ferric chloride hexahydrate. To run the procedure, one introduces 1 mL of the sample solution in chloroform into a tube, and carefully evaporates to dryness on a steam-bath. No trace amount of the solvent should remain in the tube since it inhibits the reaction. 1 mL of water is added to the tube, then 0.5 mL of the 3-methylbenzothiazolin-2-one hydrazone reagent and 0.5 mL of O.IN sodium hydroxide. This mixture is heated at 100°C for 10 minutes, and cooled for 5 minutes in a 15°C water bath. After that, one adds 0.5 mL of IN hydrochloric acid and 2 mL of the ferric chloride reagent. The resulting solution is allowed to stand for 1 hour at room temperature, and the absorbance read at 630 nm. In a 1 cm cell an absorbance of 0.3 was obtained for 21 pg of cortisone, 18 pg of hydrocortisone, 17 pg of prednisone, or 19 pg of prednisolone. 

The activating energy of the replacement is calculated to be 28,000 2000 calories. It is estimated that the displacement of 1 per cent, of arsenic from a normal solution of arsenic trichloride at room temperature and 100 atm. of hydrogen would require 1140 years. Increase in the concentration of hydrochloric acid accelerates the reaction, which is inhibited by the presence of sodium chloride, and the reaction appears to be ionic rather than molecular.3... 

Procedure Suspend 100 mg of sample in 80 mL of 0.02 N hydrochloric acid in a 100-mL volumetric flask, and set aside at room temperature for 2 h. Dilute the solution to volume by adding 0.02 N hydrochloric acid. Dilute to a 1 200 solution with 0.02 N hydrochloric acid. Proceed as described above for the Standard Curve, transferring in quadruplicate a measured volume of this solution into the holes of four agar discs. After incubation, measure the zones of inhibition. From the Standard Curve, determine the Nisin concentrations, and average the results. 

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