EP0013462B1 - Dithiocarbamat/Sulfonium-Salz enthaltende Korrosionsschutzzusammensetzung und seine Anwendung in sauren Reinigungslösungen - Google Patents

Dithiocarbamat/Sulfonium-Salz enthaltende Korrosionsschutzzusammensetzung und seine Anwendung in sauren Reinigungslösungen Download PDF

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EP0013462B1
EP0013462B1 EP19790300007 EP79300007A EP0013462B1 EP 0013462 B1 EP0013462 B1 EP 0013462B1 EP 19790300007 EP19790300007 EP 19790300007 EP 79300007 A EP79300007 A EP 79300007A EP 0013462 B1 EP0013462 B1 EP 0013462B1
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Prior art keywords
acid
solution
composition
inhibitor
thiourea
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EP0013462A1 (de
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James D. Anderson
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Henkel Corp
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Amchem Products Inc
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
    • C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
    • C23G1/04—Cleaning or pickling metallic material with solutions or molten salts with acid solutions using inhibitors
    • C23G1/06—Cleaning or pickling metallic material with solutions or molten salts with acid solutions using inhibitors organic inhibitors

Definitions

  • This invention pertains to compositions for use as corrosion inhibitors in acid cleaning, acid pickling and similar acid treatments of metal.
  • this invention pertains to a synergistic combination of organic sulfur-containing compounds which together can be effectively utilized as an additive to acid cleaning solutions, particularly, those utilizing hydrochloric acid and a copper complexing thiourea for cleaning industrial systems subject to accumulations of water-insoluble deposits on the metal surfaces.
  • Acid cleaning operations are commonly employed to remove adhering substances such as mill scale and fly ash from the inner surface of vessels, tubes and related industrial processing equipment, particularly, where such equipment is fabricated from ferrous metals.
  • acid cleaning is used for example to remove lime deposits or water scale from power plant boilers and piping systems and from evaporating equipment as well as to remove scale and deposits from processing equipment in such plants as refineries, utility companies, parper mills, chemical plants and similar industrial operations. Since the acid tends to remove a portion of the basis metal with each cleaning, the use of inhibitors to reduce basis metal loss in acid cleaning can substantially extend the life of such industrial equipment.
  • Similar acid cleaning solutions are also used in acid pickling for the removal of undesirable oxide coatings from metals, usually ferrous metals, before subjecting them to further treatments such as phosphate coating, enameling, electroplating and the like.
  • the inorganic acids particularly, the mineral acids such as hydrochloric, sulfuric, nitric, and phosphoric acid are most frequently used, though others are also used depending upon the particular needs.
  • organic acids including formic acid, citric acid, mixtures of hydroxy acetic and formic acids, and acetic acid and other organic acids, such as, oxalic acid, tartic acid and alkylene polyamine carboxylic acids as well as water soluble salts and mixes of acids and salts are used.
  • hydrochloric acid perhaps the most widely used acid for chemical cleaning is hydrochloric acid, particularly, when used for the removal of scales and other unwanted deposits from steam generating equipment and from chemical and petrochemical reaction vessels.
  • Hydrochloric acid solutions are also used in oil well acidizing wherein large quantities are pumped at high rates of flow through the oil well into the oil producing formation.
  • the acid concentrations are usually high, in the order of 10% to 15% by weight and the temperatures at the bottom of the well are also high creating situations for severe corrosion of the oil well tubing by the attack of the hydrochloric acid on the metal.
  • acid inhibitors are extensively used as additives to the cleaning, acidizing or pickling solutions employed in these operations.
  • acid inhibitors have been developed and selection of a particular inhibitor will vary according to the type of acid used in the operation, the particular metal substrate and other considerations. Mixtures of inhibitors have also found considerable interest among those employing acid treatments for metal cleaning and the like, particularly, inhibitors which in combination produce an apparent synergistic effect.
  • the complexity of the inhibition phenomena is such that there are no particular criteria by which one can predict the inhibiting power or degree of inhibition that can be achieved with any particular inhibitor or combination under particular circumstances and in some instances a combination of inhibitors may result in a decrease in the inhibiting strength.
  • the metal involved is generally one of the various steel alloys. Other metals are occasionally involved, particularly, in the case of valves and fittings. Among the other metals that are involved are copper, aluminum, nickel, and nickel alloys and some of the exotic metals such as titanium, zirconium and tantalum. Generally, however, work with inhibited acids in industrial situations involves working with steel and, to a very large extent, carbon steel or mild steel.
  • the nitrogen containing compounds or amines have been found to be particularly effective as inhibitors in hydrochloric acid; though certain thio compounds or sulfur containing compounds have alkso been found to be of value. The thio compounds, however, tend to be used more frequently in conjunction with sulfuric acid.
  • the thioureas are well known as inhibitors and components or inhibitors for many acid systems but they are not generally satisfactory for organic acids unless blended with organic bases. See for example U.S. Patent Nos. 2,403,153; 2,807,585; and 2,561,510.
  • the nitrogen bases used in producing inhibitor blends might be objectionable at times, particularly, because of their tendency to form undesirable deposits on the metal surface.
  • urea derivatives particularly thiourea and a number of substituted thioureas and thiourea derivatives, are useful for removing metallic copper from scale components when used in hydrochloric acid solutions.
  • the thioureas when used with acid cleaning solutions prevent the redeposition of copper dissolved from boiler scale and the like.
  • the acid is excessively corrosive to the basis metal or steel. It has even been shown that under certain conditions, thiourea is actually an accelerator of corrosion in acid solutions. This is particularly true in the case of hydrochloric acid solutions.
  • Triphenylsulfonium chloride is also known as an inhibitor and as a component of inhibitors for sulfuric, phosphoric, hydrochloric, sulfamic, hydrofluoric, and fluosilicic acids among others. (See for example U.S. Patent No. 2,941,949.) This inhibitor, however, is more effective when combined with other appropriate inhibitors and combinations with organic amines and propargyl alcohol are known, among others.
  • dithiocarbamate salts and esters have also been previously disclosed for use as inhibitors though the dithiocarbamates are not utilized as acid inhibitors and are not known to be effective inhibitors in hydrochloric acid/thiourea cleaning solutions; nor are the dithiocarbamates generally considered for use in combination with other inhibitors particularly sulfonium salts and thioureas.
  • U.S. Patent No. 2,723,232 which discloses the use of dithiocarbamate salts as inhibitors in certain environments also states that the dithiocarbamic acid salts function in a corrosive environment in which direct acid attack upon the ferrous metal is a minor factor. Thus, the dithiocarbamates appear as unlikely candidates for inhibitor blends in industrial acid cleaning.
  • the metal loss experienced with the best currently available inhibitors, including known inhibitor combinations, used for industrial cleaning with hydrochloric acid and thiourea is on the order of 0.01 lb. per square foot (0.049 kg per square metre) of surface in 24 hours of exposure. The industry goal has been set at less than 0.005 lbs/sq ft/24 hours (0.024 kg/sq m/ 24 hours).
  • an object of this invention to provide an acid cleaning solution with increased inhibiting strength thereby reducing the loss of basis metal during scale removal and cleaning operations.
  • Another object of this invention is to provide novel acid inhibitor combinations of greater inhibiting power than could be achieved heretofore. It is a further object of this invention to provide inhibitor combinations which when used in hydrochloric acid cleaning with a urea derivative provide a substantial reduction in metal loss. Still other objects and advantages will be apparent from the description of the invention which follows.
  • the invention provides a composition for inhibiting acid corrosion characterised in that it contains a blend of a sulfonium salt and of a dithiocarbamic acid compound of the general formula: wherein R 1 , R 2 and R 3 , which may be the same or different, each represents a hydrogen atom or an optionally substituted alkyl, alkenyl, alkynyl, aralkyl or cyclic group, M (+)n represents a monovalent or multivalent cation, and n is 1 to 3.
  • the composition is particularly useful for chemical cleaning with solutions of hydrochloric acid and thiourea.
  • the composition comprises a sulfonium salt preferably triphenylsulfonium chloride and a certain dithiocarbamate preferably benzyl-N-methyl dithiocarbamate in a preferred ratio of about 1 part by weight of the benyzyl-N-methyl dithiocarbamate for each 2 to 3 parts by weight of triphenylsulfonium chloride.
  • a combination of: (A) an acid inhibitor of the sulfonium salt type and (B) a certain dithiocarbamic acid or derivative thereof such as its ester or salt has unusually high inhibiting strength in hydrochloric acid cleaning solutions containing a urea derivative as a copper complexing agent.
  • the two component acid inhibitor combination can be provided as a single stable composition and it is to be understood that whenever reference is made to the composition, the results can be achieved by adding the two components seperately or as a combination along with other additives.
  • the invention can be viewed as comprising a three component inhibitor composition in which the third component is thiourea or a substituted thiourea or thiourea derivative.
  • the salt is of the formula: wherein R 4 , R 5 and R 6 , which may be the same or different, each represents an optionally substituted hydrocarbon radical, such as, for example, an optionally substituted alkyl, aryl, or aralkyl radical, and X represents an acid anion, preferably an anion of a strong mineral acid.
  • R 4 , R 5 or R 6 represents a substituted hydrocarbon radical
  • the substituents can be one or more of the same or different substituents examples of which include hydroxy, amino, halo- and alkyl groups.
  • R", R" or R 6 can represent an alkaryl radical.
  • radicals R 4 , R 5 and R 6 are methyl, ethyl, propyl, nonyl, dodecyl, isobutyl, phenyl, hydroxy-phenyl, dodecyl phenyl, benzyl and 4-hydroxy-3,5-dimethylphenyl. It is preferred that at least one of the R', R 2 and R 3 radicals be an optionally substituted aryl or aralkyl radical and most preferably, each of said radicals is optionally substituted aryl, such as for example phenyl or p-chlorophenyl.
  • Examples of X, the acid anion, in Formula I above are chloride, bromide, iodide and sulfate, the first mentioned being preferred.
  • Sulfonium salts and methods for their preparation are known. For example, they can be prepared by the reaction of an aromatic hydrocarbon with a sulfur monohalide in the presence of anhydrous aluminium chloride and a halogen.
  • a sulfonium salt other than halide can be used. Salts such as the acetate can be readily obtained from the halides by simply passing an aqueous solution of the available sulfonium salt usually the chloride, for example a 50% solution of triphenylsulfonium chloride, through an appropriate ion exchange medium. Thus, the acetate can be readily obtained by using a strong base resin such as Rohm and Haas IRA 400.
  • the other essential component of the inhibitor combination is a dithiocarbamic acid compound of the formula:
  • M(+ln ) preferably represents a metal cation especially an alkali metal, e.g. sodium or potassium, an ammonium or a heavy metal multi valent cation such as lead, zinc, cadmium, antimony and the like in which instances a single cation is associated with two anion moietes.
  • the cyclic group which R 1 , R 2 or R 3 can represent can be for example a polycyclic group.
  • the cyclic group can be for example an aryl or heterocyclic group.
  • R l , R 2 or R 3 represents a substituted group
  • the substituents can be one or more of the same or different substituents, examples of which include hydroxy, amino halo- and alkyl groups.
  • R 1 , R 2 or R 3 can represent an alkaryl group.
  • R 2 or R 3 in Formula II-b above may be a dithiocarboxyl alkyl group in which case the dithiocarbamic acid compound is an alkylene bis-dithiocarbamate; preferably the alkylene moiety is lower alkylene, e.g. methylene, ethylene or propylene.
  • radicals R 1 , R 2 and R 3 are methyl, ethyl, isopropyl, octadecyl, dodecyl, decenyl, benzyl, phenyl, naphthyl, cyclopentyl, cyclohexyl, thiazolyl, abietyl, pyridyl, quinolyl or the group wherein R 7 represents alkyl, aryl or alkaryl preferably lower alkyl.
  • the preferred dithiocarbamic acid compounds are the N-substituted esters, particularly the alkyl or aralkyl esters of N- alkyl and N,N-dialkyl dithiocarbamic acid preferably benzyl-N-methyl dithiocarbamate.
  • Suitable as the dithiocarbamate compound of the inhibitor composition are known materials which are either available commercially or can be prepared in accordance with procedures known in the literature.
  • the thioureas with which the inhibitor combination of this invention is effective are those which have been found useful in acid cleaning of industrial equipment, such as boilers, and particularly those which function as copper complexing agents.
  • the thiourea compounds used for this purpose can be represented by the formula: wherein R 8 , R 9 , R' o and R" may be the same or different and each represents hydrogen, or an optionally substituted alkyl, aralkyl, heterocyclic or aryl group. When the group is substituted, the substituents can be such functional groups as halogen, amino, hydroxy, or common radicals containing nitrogen, oxygen or sulfur.
  • Suitable thioureas of Formula III are for example: thiourea, 1-methyl- thiourea, 1,3-diethylthiourea, 1-phenylthiourea, 1-phenyl-3(2 hydroxyethyl) thiourea, methylolthiourea and the like.
  • the thioureas are usually used in acid solutions to be inhibited in concentrations as low as .001 g/liter of acid solution and as high as 100 g/liter.
  • concentrations as low as .001 g/liter of acid solution and as high as 100 g/liter.
  • concentration is determined by the nature of the acid solution, the copper content of the scale to be removed, the temperature at the time of exposure to the metal and other inhibitors used in making inhibitor blends.
  • a commonly used industrial cleaning solution has about 7% (wt/wt) hydrochloric acid and about 1% (wt/vot) thiourea.
  • the inhibitor composition of this invention can be conveniently used by adding it to the acid cleaning solution used in the customary manner.
  • the acid solution is generally selected in accordance with the nature of the incrustations with the non-oxidizing acids and especially the inorganic non-oxidizing acids being preferred.
  • Hydrochloric, sulfuric or phosphoric are the particular acids most commonly used.
  • Hydrochloric acid is generally used at a concentration of between 5 to 25% by weight; sulfuric at a concentration of about 5 to 15% by weight and phosphoric at about 10 to 25% by weight. Higher or lower concentrations of these acids are also used depending upon specific conditions and type of acid treatment involved.
  • oil well acidizing may utilize hydrochloric acid at concentrations of 30% by weight or higher whereas pickling operations may utilize concentrations as low as about 1 % acid by weight in the bath.
  • Aqueous solutions of hydrochloric acid preferably at a concentration of about 5 to about 10% by weight are most frequently used in cleaning heating equipment and the like and the use of the inhibitor combination of this invention will be described with particular reference to such cleaning operations though it is to be understood that the combination will find use in other acid treating situations of the type described above and elsewhere herein, whenever attack on the basis metal is a problem and particularly when thiourea or a thiourea derivative is used with the acid.
  • Typical of cleaning treatments with hydrochloric acid to which a urea derivative has been added is the process described in U.S. Patent No. 2,959,555 and the combination of this invention is particularly well suited to use in such processes.
  • the combination of this invention is used by adding to either the diluted or concentrated hydrochloric acid a formulated composition containing the two essential ingredients, preferably in solution in a suitable solvent, though a dry formulation can also be used.
  • a dry formulation can also be used.
  • the formulation can also be readily combined with the urea derivative preferably thiourea.
  • the inhibitor composition should be added and thoroughly mixed with the acid by stirring or agitating.
  • the inhibited solution is conveniently used by circulating it through the equipment to be cleaned. If circulation cannot be accomplished, the equipment should be filled with the inhibited acid and allowed to react with the scale and incrustations for sufficient time to remove the objectionable deposits. To estimate the proper acid concentration and cleaning time, samples of the deposits to be removed can be tested in the laboratory prior to the cleaning operation.
  • the equipment to be cleaned or the acid cleaning solution or both can be heated to speed the cleaning action.
  • the heating is preferably done prior to beginning the cleaning operation and generally a greater amount of inhibitor composition is used at higher temperatures.
  • the cleaning temperature can be chosen by testing with a representative sample of the metal and deposits to be cleaned. The amount of inhibitor used can also be determined by similar testing.
  • the amount of sulfonium salt and dithiocarbamate inhibitors used to provide the effective acid inhibitor of this invention can be varied over a wide range, depending upon the particular acid used in the cleaning solution, the basis metal, the temperature and other factors.
  • the ratio in which the two essential components are utilized does not appear to be critical and the proportions can also be varied over a wide range.
  • dithiocarbamate e.g. benzyl-N-methyl dithiocarbamate
  • sulfonium salt e.g. triphenylsulfonium chloride.
  • sulfonium salt e.g. triphenylsulfonium chloride.
  • sulfonium salt e.g. triphenylsulfonium chloride.
  • sulfonium salt e.g. triphenylsulfonium chloride
  • compositions having about 2.5 parts by weight of triphenylsulfonium chloride for each part by weight of benzyl-N-methyl dithiocarbate have been found to be particularly effective in hydrochloric acid/thiourea systems.
  • the inhibitor combination of this invention can be added to the cleaning solution as separate additives or can be conveniently formulated in a concentrated inhibitor composition in liquid or dry form along with the usual formulating ingredients.
  • the amounts of essential inhibiting ingredients in the formulation will comprise about 10 to 80% by wt. of the total formulated concentrate; the remainder consisting of solvent preferably butyl cellosolve and other conventional formulated ingredients.
  • the product can also be supplied as dry powder formulation along with other ingredients or as a dry formulation it can have nearly 100% active ingredients, i.e. essential only sulfonium salt and dithiocarbamate.
  • a formulated composition containing as the essential inhibitor composition a mixture of triphenyl sulfonium chloride and benzyl-N-methyl dithiocarbamate can be easily prepared by blending the essential ingredients in a water miscible solvent along with other additives generally employed in formulating inhibitor compositions.
  • solvent there can be utilized any water miscible solvent in which the two essential components are soluble and which is stable to acid cleaning solution in use.
  • Suitable additives include materials which increase acid solubility of the composition and oil dissolution.
  • Other additives known to the art may be included to get a homogeneous concentrate and to aid in solubilization of the essential components. In general, these additives are surface active agents and solvents for the other components comprising the composition.
  • Other ingredients such as antifoaming agents, diluents to adjust the volume, buffers to adjust pH and the like which are typically utilized in formulating may be included and are intended to come within the scope of this invention.
  • any surface active agent compatible with the other components of the composition can be used including anionic, cationic and nonionic surface active agents with the nonionic being preferred.
  • nonionic surface active agents are the ethoxylated secondary alcohols and ethoxylated nonyl phenols.
  • surfactants that are particularly suitable in formulating the inhibitor compositions of this invention, there can be mentioned the following: Igepal CO-850 available from the Gaf Corp.; Makon 20 available from Stepan Chemical, Retzanol NP200 manufactured by Retzloff; Surfonic N200 manufactured by Jefferson; T Det N20 manufactured by Thompson Hayward and Tergitol NP40 manufactured by Union Carbide Corporation.
  • the essential inhibitor ingredients of this invention can be combined with other inhibitors which may also contain other additive materials or they can be formulated along with such other inhibitors as an additional active ingredient.
  • Other inhibitors that may be blended with the synergistic combination of sulfonium salt and dithiocarbamic acid derivative include for example propargyl alcohol, ammonium thiocyanate, mercapto benzothiazole, the Mannich bases and the like.
  • the inhibitor complex of this invention which is particularly useful for reducing the basis metal attack of hydrochloric acid/thiourea cleaning solutions can be formulated by combining the inhibitor composition with the thiourea to provide a single additive to hydrochloric acid thereby facilitating make-up of the inhibited hydrochloric acid/thiourea cleaning solution.
  • the combination when used with a conventional hydrochloric acid/thiourea cleaning solution provides a substantial reduction in basis metal loss as compared to acid corrosion inhibitors presently employed in such acid cleaning solutions.
  • the reduction in metal loss achieved by using this combination of inhibitors, particularly, in the case of mild steel is significantly greater than can be achieved with either inhibitor separately.
  • the combination is preferably added to the particular acid composition as the formulated concentrate utilized in an amount sufficient to inhibit attack of the particular acid on the metal which is exposed thereto.
  • the amount of inhibiting composition that is indicated will vary depending upon a number of factors, some of which can be readily controlled including the concentration of the acid and the temperature at which the operation is conducted. Generally, the amount of inhibitor to be utilized at high temperature is greater; likewise, the amount to be utilized at higher acid concentrations is greater.
  • the range of inhibitor concentrations over which the degree of inhibition varies significantly with increase or decrease in inhibitor concentration at a given temperature is relatively narrow. So also the range of inhibitor concentration over which the degree of inhibition varies for any given cleaning acid concentration is relatively narrow.
  • the amount of inhibitor combination in accordance with this invention will be at least about 0.01 % by volume and usually between about 0.1 % and about 1.0 preferably .1 to .25% based upon a ratio of about 2.5 parts of triphenylsulfonium chloride for each part of benzyl-N-methyl dithiocarbamate utilized at a temperature in the range of about 150°F (66°C) to about 200°F (93°C).
  • inhibitor compositions containing about 20 to 50% by weight, preferably 20 to 30% by weight, of active ingredients (sulfonium salt and dithiocarbamate) is used in an amount sufficient to provide at least about 0.05% by volume of inhibitor in the cleaning solution.
  • the inhibitor compositions of this invention while best suited for inhibiting the attack of hydrochloric acid in the presence of thiourea can also be employed in applications where acid inhibitors are generally utilized, for example, in metal pickling operations and oil well acidizing processes. While particularly effective results have been obtained with the inhibitor combination in treatment of ferrous metals, particularly mild steel, the inhibitor combination can also be utilized to protect against acid attack on other metals such as copper, brass, stainless steel and other alloys. As will become evident from the examples which follow, the particular synergistic effect obtained with the inhibitor combination provides a special advantage in the case of hydrochloric acid/thiourea cleaning. However, the high degree of inhibiting power provided by the combination makes it suitable for a multitude of applications.
  • Benzyl-N-methyl dithiocarbamate which is representative of the dithiocarbamates suitable for use in the compositions of this invention, is a commercially available product. If desired, it can also be prepared from readily available starting materials and the entire reaction product can be used in formulating the inhibitor composition.
  • a suitable method for preparing benzyl-N-methyl dithiocarbamate is as follows:
  • the acetone is distilled off.
  • the contents of the flask are then placed into a separatory funnel and the product is extracted from the bottom as an "oil-like" substance which is drained into a Petri dish and allowed to crystallize.
  • the benzyl-N-methyl dithiocarbamate product is broken up and used "as is" in preparing the inhibitor formulations.
  • Other dithiocarbamate products can be prepared by analogous procedure also using known, available starting materials.
  • the reaction products can be used as is in formulating the corresponding inhibitor compositions.
  • An inhibitor composition was prepared with ingredients in the following amounts:
  • the composition is prepared by combining the ingredients in a blending vessel equipped with a stirrer.
  • the benzyl-N-methyl dithiocarbamate is first dissolved in the butyl cellosolve.
  • the remainder of the ingredients are then added in the order listed, while stirring. Stirring is continued until a homogeneous mixture is obtained.
  • the final product is a clear liquid.
  • the mixture is preferably filtered to remove unwanted impurities which may be carried in with the starting materials.
  • the clear liquid composition has a specific gravity of 1.029 ⁇ .005 at 60° F (16°C) before putting it into containers for shipment.
  • Example 2 This example illustrates formulations having different concentration and ratio of ingredients than that of Example 2. The components were combined in a similar manner.
  • the inhibiting strength of the composition was determined as follows:
  • a corrosion inhibitor composition of the type sold commercially for industrial cleaning with hydrochloric acid was prepared and tested in hydrochloric acid solutions with and without thiourea.
  • the corrosion inhibitor was prepared by combining a rosin amine inhibitor of the type disclosed in U.S. Patent No. 2,758,970 with triphenylsulfonium chloride and propargyl alcohol.
  • inhibitors are available for example under the brand name Rodine sold by Amchem Products, Inc.
  • a typical inhibitor of this type has the following approximate composition:
  • Example 5 An inhibitor composition in accordance with Example 5 was tested for corrosion inhibition as described in Example 4 using a 7% hydrochloric acid test solution maintained at 150°F (66°C) for 6 hours. Thiourea was added in amounts as indicated in Table I.
  • This example shows the greatly improved inhibiting power of the compositions of Examples 1 and formula A of 3 as compared to the prior art compositions of Example 5 in a hydrochloric acid and thiourea cleaning solution.
  • the tests were carried out as in Example 4 above using as a test solution hydrochloric acid cleaning compositions containing thiourea or a thiourea derivative as a copper complexing agent in amounts as indicated.
  • the concentration of hydrochloric acid was 7% (wt/wt).
  • the test was done at 150°F (66°C) for 6 hours. The results are as shown in Table II.
  • This example demonstrates the synergistic corrosion inhibiting effect of the triphenyl sulfonium salt and dithiocarbamate combination.
  • the tests were carried out as in the preceding examples using amounts of test compositions as indicated in Table III. The tests were done with 7% wt/wt hydrochloric acid solutions maintained at 150°F (66°C) for 6 hours.
  • the triphenylsulfonium chloride was formulated without the dithiocarbamate by substituting an equal weight amount of butyl cellosolve for the dithiocarbamate.
  • This formulation identified as Formulated TPSC has the following composition:
  • This example illustrates the use of the inhibitor combination of this invention in conjunction with another inhibitor.
  • the tests were carried out as in the preceding examples using 1% wt/vol thiourea in a 7% wt/wt hydrochloric acid solution at 150°F (66°C) for 6 hours.
  • the weight loss results are shown in Table IV.
  • This example illustrates the inhibiting power of the combination with change in the ratio of amount of triphenylsulfonium salt to the amount of dithiocarbamate.
  • Tests were carried out in the same manner as above using 7% (wt/wt) hydrochloric acid with 1% (wt/vol) thiourea at 150°F (66°C) for 6 hours. Results are shown in Table V.
  • Example 4 illustrates the inhibiting power at various concentrations of the synergistic combination of triphenylsulfonium chloride and benzyl-N-methyl dithiocarbamate (Example 4).
  • Test procedures are the same as in previous examples using 7% hydrochloric acid (wt/wt) with 1 % thiourea (wt/vol) at 150°F (66°C) for 6 hours. Results are shown in Table VII.

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Claims (14)

1. Zusammensetzung zur Inhibierung der Säurekorrosion dadurch gekennzeichnet, daß sie eine Mischung eines Sulfoniumsalzes und einer Dithiocarbaminsäure-Verbindung der allgemeinen Formel
Figure imgb0028
worin R1, R2 und R3 gleich oder verschieden sein können und jeweils ein Wasserstoffatom oder eine gegebenenfalls substituierte Akyl-, Alkenyl-, Alkynyl-, Aralkyl- oder zyklische Gruppe, M ein einwertiges oder mehrwertiges Kation und n 1 bis 3 bedeuten, enthält.
2. Zusammensetzung gemäß Anspruch 1, dadurch gekennzeichnet, daß das Sulfoniumsalz der allgemeinen Formel
Figure imgb0029
worin R4, R5 und RB gleich oder verschieden sein können und jeweils einen gegebenenfalls substituierten Alkyl-, Aryl- oder Aralkylrest und X ein Säureanion bedeuten, entspricht.
3. Zusammensetzung gemäß Anspruch 1 oder Anspruch 2, dadurch gekennzeichnet, daß das Sulfoniumsalz Triphenylsulfoniumchlorid ist.
4. Zusammensetzung gemäß einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß R1, R2 und R3 gleich oder verschieden sein können und jeweils ein Wasserstoffatom oder eine Alkyl-, Alkenyl-, Alkynyl-, Aralkyl- oder Arylgruppe bedeuten.
5. Zusammensetzung gemäß einem der Ansprüche 1 bis 4 dadurch gekennzeichnet, daß die Dithiocarbaminsäure-Verbindung Benzyl-N-Methyldithiocarbamat ist.
6. Zusammensetzung gemäß einem der Ansprüche 1 bis 5 dadurch gekennzeichnet, daß sie zwei bis drei Gewichtsteile, und vorzugsweise etwa 2,5 Gewichtsteile Sulfoniumsalz je Gewichtsteil der Dithiocarbaminsäure-Verbindung und gegebenenfalls ferner ein oberflächenaktives Mittel enthält.
7. Wässrige saure Reinigungslösung enthaltend einen Säurereiniger und einen Inhibitor gegen Säurekorrosion dadurch gekennzeichnet, daß als Inhibitor eine Zusammensetzung gemäß einem der Ansprüche 1 bis 6 verwendet wird, die in einer solchen Menge anwesend ist, daß Konzentrationen von mindestens 0,008 Gew.-% des Sulfoniumsalzes und mindestens 0,003 Gew.-% der Dithiocarbaminsaure-Verbindung in der Säurelösung erhalten werden.
8. Lösung gemäß Anspruch 7, dadurch gekennzeichnet, daß die Säure in der genannten wässrigen sauren Reinigungslösung Salzsäure ist.
9. Lösung gemäß Anspruch 8 dadurch gekennzeichnet, daß sie Salzsäure in einer Menge zwischen 5 und 10 Gew.-% zusammen mit der Inhibitor-Zusammensetzung in einer Menge von mindestens 0,05 Volumen-% enthält.
10. Lösung gemäß einem der Ansprüche 7 bis 9 dadurch gekennzeichnet, daß sie weiterhin ein Kupfer-Komplexierungsmittel enthält.
11. Lösung gemäß einem der Ansprüche 7 bis 10 dadurch gekennzeichnet, daß sie mindestens 0,001 Gramm/Liter eines Harnstoffderivates darin gelöst enthält.
12. Lösung gemäß Anspruch 11 dadurch gekennzeichnet, daß das Harnstoffderivat, welches in der Säure-Reinigungslösung gelöst ist Thioharnstoff und/oder Methylolthioharnstoff ist.
13. Lösung gemäß einem der Ansprüche 7 bis 12 dadurch gekennzeichnet, daß sie als Säure Salzsäure und als Inhibitor-Zusammensetzung Triphenylsulfoniumchlorid in einer Menge ausreichend um zumindest 0,08 Gramm je Liter davon in Lösung vorliegen zu haben, Benzyl-N-Methyldithiocarbamat anwesend in einer Menge ausreichend um mindestens 0,03 Gramm je Liter davon in der Lösung zu liefern und Thioharnstoff anwesend in einer Menge ausreichend um mindestens 0,001 Gramm je Liter davon in Lösung zu liefern enthält.
14. Verfahren zur Reinigung von industriellen Ausrüstungsgegenständen die eine Wasserverkrustung oder andere ungewünschte wasserunlösliche Ablagerungen aufweisen, unter Verwendung einer wässrigen sauren Reinigungslösung enthaltend Inhibitoren gegen Säurekorrosion dadurch gekennzeichnet, daß die eingesetzte Säurelösung inhibiert ist bezüglich eines Angriffs des Grundmetalls der industriellen Ausrüstungsgegenstände durch Verwendung einer Reinigungslösung gemäß einem der Ansprüche 7 bis 13.
EP19790300007 1979-01-03 1979-01-03 Dithiocarbamat/Sulfonium-Salz enthaltende Korrosionsschutzzusammensetzung und seine Anwendung in sauren Reinigungslösungen Expired EP0013462B1 (de)

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Application Number Priority Date Filing Date Title
DE7979300007T DE2965334D1 (en) 1979-01-03 1979-01-03 Dithiocarbamate/sulfonium salt corrosion inhibitor composition and its use in acidic cleaning solutions
EP19790300007 EP0013462B1 (de) 1979-01-03 1979-01-03 Dithiocarbamat/Sulfonium-Salz enthaltende Korrosionsschutzzusammensetzung und seine Anwendung in sauren Reinigungslösungen

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Application Number Priority Date Filing Date Title
EP19790300007 EP0013462B1 (de) 1979-01-03 1979-01-03 Dithiocarbamat/Sulfonium-Salz enthaltende Korrosionsschutzzusammensetzung und seine Anwendung in sauren Reinigungslösungen

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EP0013462A1 EP0013462A1 (de) 1980-07-23
EP0013462B1 true EP0013462B1 (de) 1983-05-11

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US5247087A (en) * 1992-05-13 1993-09-21 Baker Hughes Incorporated Epoxy modified water clarifiers
US10301553B2 (en) 2017-02-28 2019-05-28 Ecolab Usa Inc. Use of sulfonium salts as hydrogen sulfide inhibitors
US10900128B2 (en) 2018-08-29 2021-01-26 Championx Usa Inc. Use of sulfonium salts as corrosion inhibitors

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DE962489C (de) * 1954-02-10 1957-04-25 Dehydag Gmbh Sparbeizmittel zum Schutze von Metallen bei der Behandlung mit sauren Mitteln
FR1283323A (fr) * 1960-12-23 1962-02-02 Cie D Applic Chimiques A L Ind Produit inhibiteur de l'attaque des métaux par les acides forts
US3819527A (en) * 1972-11-06 1974-06-25 Amchem Prod Composition and method for inhibiting acid attack of metals

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EP0013462A1 (de) 1980-07-23

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