สารยับยั้งการกัดกร่อนของโลหะ

Abstract

DEPCT6424 / 04 / 2563 การประดิษฐ์นี้ที่เกี่ยวข้องกับองค์ประกอบของกรดซัลโฟนิกอย่างน้อยหนึ่งชนิดในการ รวมกันกับสารประกอบไนโตรซิลอย่างน้อยหนึ่งชนิดในปริมาณที่มีประสิทธิผลที่ทำหน้าที่เป็น สารยับยั้งการกัดกร่อนของโลหะโดยกรดซัลโฟนิกอย่างน้อยหนึ่งชนิดดังกล่าว -----------------------------------------------------------การประดิษฐ์นี้ที่เกี่ยวข้องกับองค์ประกอบของซัลโฟนิกแอซิดอย่างน้อยหนึ่งชนิดในการรวมกันกับสารประกอบไนโตรซิลอย่างน้อยหนึ่งชนิดในปริมาณที่มีประสิทธิภาพที่ทำหน้าที่เป็น สารยับยั้งการกัดกร่อนของโลหะโดยซัลโฟนิกแอซิดอย่างน้อยหนึ่งชนิดดังกล่าว

Description

Metallic corrosion inhibitors

[0001] The present invention relates to the field of corrosion, by sulfonic acids, of passivatable metals and alloys, in particular based on iron, nickel, titanium, copper, aluminum, molybdenum, manganese, lead, and their alloys, as well as the pairs of these metals or alloys obtained by contact (crimping, riveting, bolting, welding, brazing).

[0002] The invention relates more particularly to the protection of said metals against corrosion by sulfonic acids, and in particular organosulfonic acids.

[0003] Sulfonic acids, more specifically organosulfonic acids, and in particular methanesulfonic acid (MSA), para-toluenesulfonic acid (PTSA), benzenesulfonic acid (BS), trifluoromethanesulfonic acid are strong acids widely used in many applications, including catalysis and surface treatment (electroplating, pickling, cleaning, descaling, and others).

[0004] However, it has been observed that aqueous solutions of such sulfonic acids corrode metals, with corrosion rates depending on the acid concentration, temperature, and the nature of the metal. For example, at room temperature, 304L or 1.4307 stainless steel is corrodible at MSA concentrations exceeding 5 wt% in water. Such corrosion risks are unacceptable in many applications, particularly for the storage of these acids, especially when they are in aqueous solution.

[0005] To protect stainless steels against corrosion by sulfonic acids (particularly APTS and poly(styrenesulfonic acid)), patent application JP 07-278854 proposed adding a copper salt to these acids. This document specifically addresses the protection of stainless steel equipment (AISI 304 and 316 types) used in workshops synthesizing alcohols from olefins and water in the presence of a sulfonic acid as a catalyst. The temperature range exemplified in this document extends from ambient temperature up to approximately 100°C.

[0006] In the article entitled "Corrosion of stainless steel during acetate production" published in July 1996 in the journal "Corrosion Engineering", vol. 2, no. 7, page 558, of JS Qi and JC Lester indicate that the use of copper sulfate during esterification in the presence of sulfuric acid or para-toluenesulfonic acid significantly reduces the corrosion of AISI 304L and 316L stainless steels.

[0007] However, these copper salts, which inhibit corrosion, have drawbacks: static tests carried out on compositions of AMS and copper(II) salts at temperatures between 100°C and 150°C show that a thin, poorly adhering layer of metallic copper forms on the surface of the tested materials (AISI 304L and 316L stainless steel). During industrial implementation of this method, sedimentation of metallic copper particles at the bottom of the reactor was observed, which can seriously damage the recycling pumps or compromise the quality of the manufactured product. An additional filtration step is therefore necessary to remove these copper particles from the film deposited on the reactor walls.

[0008] In fact, during changes in operating conditions (e.g., temperature, pressure, stirring speed), this protective film detaches very easily. Furthermore, heavy metals are defined as environmental pollutants, and therefore the release of such compounds into effluents is problematic.

[0009] It was also disclosed in EP-A-0 931 654 that it is possible to inhibit the corrosion of stainless steels in organosulfonic acid (OMS) by adding at least one oxidant selected from cerium(IV), iron(III), molybdenum(VI), or vanadium(V) salts or oxides, nitrites, and persulfates. Furthermore, B. Gaur and H.S. Srinivasan (British Corrosion Journal, 34(1), 1999, 63–66) showed that the addition of ferric or nitrate ions produces an inhibitory effect on OMS corrosion in various steels.

[0010] It can therefore be observed that the various sulfonic acid corrosion inhibitors for metals currently available, such as metal salts, are toxic to the environment. It is therefore highly desirable to have access to sulfonic acid corrosion inhibitors for metals that are more effective, less toxic, and more environmentally friendly.

[0011] Certain applications, particularly stripping and descaling, use AMS-based solutions formulated with the addition of other products such as surfactants or metal ion complexing agents (sulfamic, citric, or oxalic acid). can cancel out the inhibitory effect of oxidizing metal salts or lead to high doses of inhibitors, which are incompatible with environmental protection.

[0012] It has now been found that metals, especially those mentioned previously, such as ferric metals, copper, aluminum, and their alloys, and in particular steels, can be effectively protected over a wide temperature range against corrosion by sulfonic acids, more specifically organosulfonic acids, preferably alkanesulfonic acids, preferably even more preferably by AMS, by adding to the medium an effective amount of at least one compound chosen from nitrous acid or a compound capable of forming nitrous acid.

[0013] According to a first aspect, the present invention relates to the use of at least one compound of general formula (1): O=N-OX (1 ), in which X is chosen from: • H; NO; • an alkyl radical R, linear or branched, comprising 1 to 6 carbon atoms; • an aryl radical Ar possibly substituted, in particular by at least one alkyl radical R; • a -SO2-G radical, where G represents H, OH, R, OR, OM, Ar, OAr, NH2, NHR and NRR', where R and Ar are as defined previously, R' represents an alkyl radical, linear or branched, comprising from 1 to 6 carbon atoms, and M represents a monovalent or divalent metal cation, preferably an alkali or alkaline earth metal cation; and • a radical -CO-G, where G is as defined previously, to limit, or even avoid, the corrosion of metals by sulfonic acids.

[0014] When X represents the hydrogen atom, the compound with formula (1) is nitrous acid. When X represents -NO, the compound with formula (1) is nitrous anhydride.

[0015] According to a preferred embodiment of the present invention, X represents -SO2-G, and preferably further -SO2-G where -G represents -OH, in which case the corrosion inhibitor is nitrosyl acid sulfate (SHN; CAS No. 7782-78-7). According to another preferred aspect, X represents SO2-G, where G represents an alkyl radical R, preferably the methyl radical, in which case the corrosion inhibitor (CAS No. 117933-98-9) is the reaction product of methanesulfonic acid (or its chloride) with nitrous acid.

[0016] According to one embodiment, X is chosen from: NO; • an alkyl radical R, linear or branched, comprising 1 to 6 carbon atoms; • an aryl radical Ar possibly substituted, in particular by at least one alkyl radical R; • a -SO2-G radical, where G represents H, OH, R, OR, OM, Ar, OAr, NH2, NHR and NRR', where R and Ar are as defined previously, R' represents an alkyl radical, linear or branched, comprising from 1 to 6 carbon atoms, and M represents a monovalent or divalent metal cation, preferably an alkali or alkaline earth metal cation; and • a radical -CO-G, where G is as defined previously.

[0017] The work of Y. Cètre (“Prevention and control of corrosion”, ISBN 2-88074-543-8, (2004), Presses polytechniques et universitaires romandes, Lausanne, CH, pp. 661-676) showed that the corrosion of AISI 304L type stainless steel by 70% sulfuric acid can be inhibited due to the presence of nitrosyl acid sulfate (SHN), an inherent presence in the sulfuric acid synthesis process.

[0018] SHN, which is known to be an inherent impurity in the preparation of sulfuric acid, is, in its pure form, a highly hygroscopic, unstable solid that reacts violently with water and produces toxic fumes (NOₓ). x ) in the presence of moisture.

[0019] Other derivatives of nitrous acid, as well as nitrous acid itself, are unstable just like SHN.

[0020] Furthermore, it is well known to those skilled in the art of metal corrosion that corrosion inhibitors are acid-specific. For example, corrosion inhibitors described in the literature and effective for protecting stainless steels in sulfuric acid are ineffective against phosphoric acid and increase the corrosion rate in hydrochloric acid. Conversely, corrosion inhibitors effective against hydrochloric acid are completely unsuitable for sulfuric acid.

[0021] The research work of the present inventors has led to the discovery that certain nitrosylated derivatives exhibit corrosion-inhibiting activity on metals. by sulfonic acids, and more particularly by organosulfonic acids. The metals considered are more specifically steels, and in particular common stainless steels (for example of type AISI 304L and AISI 316L), but also more generally any stainless steel as defined in standard NF EN 10088-1.

[0022] Thus, according to another aspect, the invention relates to a composition comprising at least one compound of formula (1) as defined above, and at least one sulfonic acid, as defined above, preferably at least one organosulfonic acid, preferably at least one alkanesulfonic acid, preferably even more the AMS.

[0023] By effective quantity is meant a quantity of compound(s) of formula (1) between 1 ppm and a few percent, for example 10%, preferably between 5 ppm and 1000 ppm, preferably again between 10 ppm and 800 ppm, by weight relative to the total weight of the composition.

[0024] The present invention also relates to a method for protecting metals against corrosion by sulfonic acids, in particular passivatable metals and alloys, in particular those based on iron, nickel, titanium, copper, aluminum, molybdenum, manganese, lead, and their alloys, as well as the (galvanic) couples of these metals or alloys of these metals or alloys obtained by contact (crimping, riveting, bolting, welding, brazing), characterized in that the sulfonic acid coming into contact with said metals is a composition as defined above comprising at least one compound of formula (1) as defined above.

[0025] The compounds of formula (1) are either commercially available or, when unstable, prepared according to known procedures or procedures available in the scientific literature, patent literature, or on the internet. When unstable, the compounds of formula (1) are advantageously prepared immediately before being added to the sulfonic acid, or the composition containing it.

[0026] As an example, nitrosyl acid sulfate (NHS) can be obtained by various methods known to those skilled in the art, including bubbling a stoichiometric mixture of nitric oxide (NO) and nitrogen dioxide (NO2) through oleum (a mixture of H2SO4, SO3). The NHS thus obtained in solution in the oleum can then be directly added to the sulfonic acid, or to the composition containing it.

[0027] Thus, at least one compound of formula (1) can be added to at least one sulfonic acid, the corrosive effect of which on metals is to be limited or even prevented, according to any method known in itself, by simple addition and possible mixing.

[0028] According to an alternative, the compound of formula (1) can be generated in situ by adding a precursor of the compound of formula (1) which, upon contact with the sulfonic acid(s), is transformed into said compound of formula (1). Thus, for example, the compound O=N-OSO2CH3 (CAS Reg. no. 1 17933-98-9) can be prepared by adding a nitrogen oxide / nitrogen dioxide mixture to methanesulfonic acid.

[0029] In the present invention, sulfonic acid is preferably understood to mean acids of formula R-SO3H, where R represents a saturated hydrocarbon chain, linear or branched, comprising 1 to 4 carbon atoms, or an aryl radical optionally substituted by a saturated hydrocarbon chain, linear or branched, comprising 1 to 4 carbon atoms, and optionally substituted, in whole or in part, by one or more halogen atoms, identical or different.

[0030] The saturated hydrocarbon chain, linear or branched, comprising 1 to 4 carbon atoms can be substituted, in whole or in part, by one or more halogen atoms chosen from fluorine, chlorine and bromine, and in particular, the hydrocarbon chain can be perhalogenated, more particularly perfluorinated.

[0031] By "aryl" we mean an aromatic radical, preferably phenyl or naphthyl, more preferably phenyl.

[0032] Thus, and without limitation, the sulfonic acids included within the scope of the present invention are organosulfonic acids preferably selected from methanesulfonic acid, ethanesulfonic acid, n-propanesulfonic acid, acid / ' so-propanesulfonic acid, n-butanesulfonic acid, acid / ' so-butanesulfonic acid, sec-butanesulfonic acid, terf-butanesulfonic acid, trifluoromethanesulfonic acid, para-toluenesulfonic acid, benzenesulfonic acid and mixtures of two or more of them in any proportions.

[0033] According to a particularly preferred embodiment, the sulfonic acid used in the context of the present invention is methanesulfonic acid, ethanesulfonic acid, trifluoromethanesulfonic acid or para-toluenesulfonic acid, most preferably the sulfonic acid used is methanesulfonic acid.

[0034] The compositions according to the present invention, comprising at least one sulfonic acid and an effective amount of at least one corrosion inhibitor of formula (1), are acidic compositions that can be used in any field where said sulfonic acids are commonly used. As previously stated, the acidic compositions according to the invention have the advantage of being less corrosive, or even non-corrosive, compared to the same acidic compositions not comprising corrosion inhibitor(s).

[0035] The compositions according to the present invention can be of any type, liquid, in more or less dilute aqueous solutions, or in the form of gels or foaming gels, the viscosities of which can vary in large proportions.

[0036] According to one embodiment, the compositions according to the present invention are used in pure form or diluted with various components, as indicated below.

[0037] As a general rule, the compositions comprise from 0.01% to 100% by weight of sulfonic acid(s) in association with at least one corrosion inhibitor of formula (1) defined previously, more generally from 0.05% to 90% by weight, in particular from 0.5% to 75% by weight, relative to the total weight of said composition, the remainder of the composition comprising a solvent and / or a diluent, preferably an aqueous solvent and / or diluent, preferably water, and possibly one or more additives, as defined later in this description.

[0038] According to a preferred embodiment, the composition of the present invention comprises at least one sulfonic acid selected from methanesulfonic acid, ethanesulfonic acid, n-propanesulfonic acid, acid / ' so-propanesulfonic acid, n-butanesulfonic acid, acid / 'so-butanesulfonic acid, sec-butanesulfonic acid, terf-butanesulfonic acid, trifluoromethanesulfonic acid, para-toluenesulfonic acid, benzenesulfonic acid, and mixtures of two or more of these in any proportion, preferably methanesulfonic acid, ethanesulfonic acid, trifluoromethanesulfonic acid, and para-toluenesulfonic acid, most preferably methanesulfonic acid, in association with at least one corrosion inhibitor compound of the formula O=N-OX, where X is selected from H, NO, an alkyl radical R, linear or branched, comprising from 1 to 6 carbon atoms, and a -SO2-G or -CO-G radical, where G represents OH or R as defined above, the whole sulfonic acid and corrosion inhibitor representing from 0.05% to 90% by weight, in particular from 0.5% to 75% by weight, of the total weight of said composition, the remainder of the composition being water.

[0039] According to a particularly preferred embodiment, the composition of the present invention comprises methanesulfonic acid, nitrosyl acid sulfate and water.

[0040] The compositions according to the present invention may optionally include one or more additives or auxiliaries commonly used in the field concerned and according to the applications intended.

[0041] Examples of additives and auxiliaries include, but are not limited to, viscosity modifiers, rheology modifiers, foaming agents, antifoaming agents, surfactants, and others, disinfectants, biocides, stabilizers, oxidizing agents, enzymes, pigments, dyes, flame retardants, flame retardants, and others.

[0042] Thus, depending on the intended uses, and if desirable or necessary, the compositions according to the invention may include one or more additives, such as those selected from: • solvents, hydrotropic or solubilizing agents (e.g. alcohols, esters, ketones, amides, and others); • biocides, disinfectants (bromoacetic acid, peracetic acid, hydrogen peroxide, chlorine dioxide, chlorine, bromine, and others); • rheological, texturizing, thickening, gelling agents (sugars, polysaccharides, alginates, silica, amorphous silica, gums and others); • complexing agents; • organic or mineral acids (e.g. sulfuric, phosphoric, nitric, sulfamic, acetic, citric, acetic, ascorbic, formic, lactic, glycolic, oxalic and others); • flame retardants; • preservatives; • anionic, cationic, non-ionic or amphoteric surfactants (such as ethoxylated alcohols and / or amino acids, alkyl- and / or aryl-sulfonates), emulsifiers, detergents, soaps, and others; • foaming agents, antifoaming agents; • antifreeze (e.g. ethylene glycol, propylene glycol, and others); • dyes, pigments; • perfumes, odor-absorbing agents; and other additives known to a person skilled in the art.

[0043] Among the complexing agents possibly present in the compositions according to the invention, we can mention in particular the complexing agents of metals, for example organic complexing agents, such as ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), (2-hydroxyethyl)-ethylenediaminetriacetic acid (HEDTA), methylglycinediacetic acid (MGDA) or nitrilotriacetic acid (NTA).

[0044] According to a preferred embodiment of the invention, the compositions may include one or more other acids, organic or mineral, among which, by way of non-limiting examples, may be cited phosphoric acid, sulfuric acid, nitric acid, carboxylic acids such as sulfamic, citric, oxalic, glycolic, acetic, ascorbic, formic, lactic acids and mixtures of two or more of them, in any proportions.

[0045] Among the solubilizing or hydrotropic agents that can be used in formulations according to the invention, sodium xylene- or cumene-sulfonates may be cited by way of example and without limitation. However, such agents are not essential in the compositions of the invention.

[0046] The quantities of additives and / or auxiliaries in the compositions of the invention can vary in large proportions and will be easily adjusted by a person skilled in the art according to the specific applications envisaged.

[0047] Generally, the compositions according to the present invention are in the form of an aqueous, organic, or hydro-organic formulation, which can be prepared as a concentrated mixture that can be diluted with water by the end user. Alternatively, the formulation can also be a ready-to-use formulation, i.e., one that does not require dilution.

[0048] According to another aspect, the compositions of the present invention can be formulated in the form of gels or foaming gels.

[0049] In the case of gel formulations, or even foaming gel formulations, the use of at least one ethoxylated amine oxide, such as, but not limited to, Cecajel® OX100 from CECA, or the Aromox ® T12 from Akzo alone or in combination with at least one dimethylalkylamine oxide provides stability to the gel, in particular to the foaming gel.

[0050] An aqueous, organic or hydro-organic formulation, in the form of a solution, gel or even in the form of a foaming gel, particularly preferred is a formulation comprising from 0.01% to 97%, preferably from 0.05% to 75%, preferably still from 0.5% to 70% by weight of methanesulfonic acid, associated with at least one compound of formula (1) as defined above.

[0051] Depending on the field and method of application, the formulation can be prepared as a concentrate, with an appropriate viscosity, then diluted before use until the expected effectiveness is obtained, in terms of viscosity and possibly foaming power.

[0052] The compositions of the present invention can, for example, be prepared from commercial acid solutions, and by way of non-limiting example, from methanesulfonic acid in aqueous solution marketed by Arkema under the name Scaleva. ® , or under the name Lutropur ® marketed by BASF, ready to use or diluted with water in the proportions indicated above.

[0053] According to one aspect of the present invention, compositions comprising at least one sulfonic acid and at least one corrosion inhibitor of formula (1) as defined above further comprise a disinfectant, in particular chlorine dioxide.

[0054] According to a preferred embodiment, chlorine dioxide can be generated in situ by adding sodium chlorite to the composition of the invention. Sodium chlorite, upon contact with a sulfonic acid, such as AMS, is converted into chlorine dioxide, a disinfectant agent, as described in patent application WO 2002 / 46095.

[0055] Compositions according to the present invention further comprising a disinfectant agent as indicated above find particularly interesting applications for cleaning and disinfecting cooling water circuits, disinfecting sanitary water and disinfecting hospital equipment.

[0056] In another respect, the compositions according to the invention are particularly useful for storing sulfonic acids, or solutions, especially aqueous solutions, of sulfonic acids. Indeed, the presence in said compositions of the present invention of at least one corrosion inhibitor eliminates the need for plastic coating films, which are generally used for storing said acids in metal tanks, particularly stainless steel tanks.

[0057] Another advantage of the compositions according to the present invention is their very good storage stability, as well as their very good temperature stability. Thus, the compositions of the invention, which can be used in numerous fields of application, can in particular be used in chemical reactions requiring the use of sulfonic acids and conducted in metallic reactors at temperatures ranging, for example, from -10°C to 200°C.

[0058] More generally, the compositions according to the present invention find applications in all fields where acidic compositions are required, in particular aqueous acidic solutions coming into contact with the metals mentioned above and whose corrosion one wishes to limit or avoid.

[0059] Such fields of application include, for example and not limited to, storage, catalytic reactions (such as esterification reactions in acid catalysis), cleaning, descaling, detergents, pickling, electroplating, surfacing (especially in the electronics field), and others.

[0060] By way of non-limiting examples, the fields of application are the stripping, cleaning, descaling and detergency of mineral and / or organic soiling in the food processing industries, such as dairies, cheese factories, early produce and meat product packaging, breweries, as well as the stripping, cleaning, and descaling of mineral residues, in cement plants, in all areas where it is necessary and desirable to remove rust, or in oil and gas operations where acidic solutions are needed for the dissolution of underground rocks, in particular carbonate rocks.

[0061] The fields of application targeted by the compositions according to the present invention are all fields where at least one sulfonic acid is stored or transported. in containers, drums, tanks, receptacles, reactors, fermenters, pipelines, pipes, tubes, valves, which are susceptible to corrosion and whose corrosion we wish to limit or even avoid.

[0062] According to another aspect, the present invention relates to the use of a composition comprising at least one sulfonic acid and at least one corrosion inhibitor of said sulfonic acid(s) as defined above for the storage of said acids, catalytic reactions or for cleaning, descaling, detergent cleaning, pickling, disinfection, electroplating, surfacing, catalytic reactions, and other purposes, at temperatures ranging from -10°C to 200°C, preferably from 0°C to 160°C.

[0063] The compositions according to the present invention, whether in liquid, gel or foaming gel form, concentrated or diluted, can be applied by any method known to those skilled in the art, and in particular under pressure, or with the aid of a spray gun.

[0064] As previously stated, the sulfonic acid comprising the corrosion inhibitor defined above is advantageously implemented in the form of a formulation, for example aqueous, organic or hydro-organic formulation, in liquid, gel or foaming gel form, as defined above.

[0065] The present invention is now illustrated by means of the following examples, which are not intended to be limiting and therefore cannot be understood as restricting the scope of the invention as claimed. Example 1: Electrochemical Test Protocols

[0066] The electrochemical test is carried out using a classic 3-electrode setup (reference electrode (saturated calomel electrode ECS), working electrode made in the material to be studied and platinum counter electrode) connected to a BIOLOGIC VMP3 or EGG 273A potentiostat.

[0067] The test specimen of the material to be tested is polished with P1000 abrasive paper, in order to have a reproducible initial state, then left in the open air for a minimum of 24 hours.

[0068] The working electrode is installed on a rotating system which allows the rotation speed to be fixed: the rotation speed is fixed at 1000 revolutions per minute.

[0069] Several types of tests using this setup were used during this study: • Potentiometric-kinetic (or voltammetric) scanning I = f(E): the variation of the potential E of the material and the measurement of the current I between it and the counter electrode allows us to estimate the behavior of the material in the environment: quality of the passive layer, estimation of the corrosion rate (Tafel method at the free corrosion potential and direct reading of the current measured at other potentials), etc. • Monitoring the material's abandonment potential (or potential-time curve) as a function of time E = f(t): Monitoring the abandonment potential of a stainless material allows us to determine whether the material is passive (negligible corrosion) or active (passive layer destroyed, significant corrosion), provided that the potentiokinetic polarization curve has been plotted beforehand. This type of test also allows us to monitor the material's behavior according to the conditions present in the environment: influence of deaeration, temperature, addition of inhibitors, etc.). Example 2: Electrochemical test showing the persistence of the inhibitor's effect

[0070] The long-lasting effect of SHN inhibition in AMS 70% (Scaleva ® , Arkema) is highlighted by monitoring the corrosion potential over time, at 40 °C.

[0071] A 316L stainless steel test specimen, measuring 35 x 23 x 3 mm, is in standard condition (polished P320 and air passivated for a minimum of 24 hours). • When immersed in 70% AMS at 40°C, the 316L stainless steel test specimen immediately depassivates (potential of the order of -250 mV / ECS). • Adding 400 ppm of SHN to the medium passively heats the 316L stainless steel of the test specimen: the potential becomes greater than 500 mV / ECS. • After 21 days under these conditions the 316L is still passive (potential greater than 500 mV / ECS).

[0072] Figure 1 shows the passivation curve as a function of time: at time t = 0, the 316L stainless steel specimen is immersed in a 70% AMS solution (Scaleva ®(Arkema) at 40°C. 316L stainless steel becomes active upon immersion. At t = 1200 seconds, 400 ppm of SHN (via a solution of approximately 60% SHN in sulfuric acid) are added using an automatic micropipette to the acid solution at 40°C. The 316L stainless steel immediately becomes passivated.

[0073] The nitrosyl acid sulfate used here is a 60% by weight solution in sulfuric acid prepared by bubbling a 1 / 1 stoichiometric mixture of nitric oxide (NO) and nitrogen dioxide (NO2) (70 g and 110 g respectively), into 830 g of oleum (H2SO / SO3 mixture: 77 / 23 by weight).

[0074] After 21 days, the steel test specimen is still passivated, indicating an absence of corrosion, even after this period of time. Example 3: Persistence of the inhibitory effect despite worsening test conditions (Temperature effect: 90°C)

[0075] This test consists of monitoring the corrosion potential over time: • The freshly polished 316L stainless steel sample is immersed in 70% Scaleva AMS ® + 100 ppm of SHN at 40°C: the sample becomes passivated immediately. • The temperature of the medium is gradually increased by increments of 10°C: after 5 days, the medium is at 90°C: the 316L stainless steel is still passive. • After 460 hours (approximately 19 days), the sample is still passive.

Claims

25 / 02 / 25681. An aqueous mixture containing at least one sulfonic acid and at least one compound of the formula ONOX, where X is chosen from NO, alkyl radicals R, straight or branched chains containing 1 to 6 carbon atoms, aryl radicals Ar, which can be selectively replaced by at least one alkyl radical R, SO2G, which is a radical where G represents H, OH, R, OR, OM, Ar, OAr, NH2, NHR, and NRR, where R and Ar are as defined above, R' represents alkyl radicals R, straight or branched chains containing 1 to 6 carbon atoms, and M represents a monovalent or bivalent metal cation, and COG, which is a radical where G is as defined above, where the compound is present in quantities effective for limiting or even preventing corrosion of metals by sulfonic acid. ----------------------------------------------------DEPCT6424 / 04 / 25631.The use of at least one compound of the general formula(1):O=N-OX(1), where X is chosen from:•H;•NO;•alkyl radical R, straight or branched chains containing 1 to 6 carbon atoms;•aryl radical Ar, which is selectively replaced, specifically by at least one alkyl radical R;•-SO2-G, which is radical in which G represents H,OH,R,OR,OM,Ar,OAr,NH2,NHR and NRR', where R and Ar are as defined above, R' represents alkyl radical R, straight or branched chains containing 1 to 6 carbon atoms. Comprising 1 to 6 carbon atoms and M representing the cation of a monovalent or bivalent metal, appropriately a cation of alkali or alkaline earth metals; and •-CO-G as a radical where G is as defined above, for limiting or even preventing corrosion of metals by sulfonic acids.

2. Using according to claim 1 where X represents -SO2-G, appropriately -SO2-G where -G represents -OH or R, R representing alkyl radical, appropriately methyl radical.3.The use under claim 1 or claim 2 where sulfonic acid is an acid of the formula R-SO3H where R represents a saturated, straight or branched hydrocarbon chain composed of 1 to 4 carbon atoms, which is either replaced wholly or partially by one or more identical or different halogen atoms, or an aryl radical which is selectively replaced by a saturated, straight or branched hydrocarbon chain composed of 1 to 4 carbon atoms, which is either replaced wholly or partially by one or more identical or different halogen atoms.4.Under any one of the preceding claims, whereby sulfonic acid is selected from methanesulfonic acid, ethanesulfonic acid, normal-propanesulfonic acid, iso-propanesulfonic acid, normal-butanesulfonic acid, iso-butanesulfonic acid, sec-butanesulfonic acid, tert-butanesulfonic acid, trifluoromethanesulfonic acid, para-toluenesulfonic acid, benzenesulfonic acid and any two or more of them in any appropriate proportion, then sulfonate acid A sulfonic acid is selected from methane sulfonic acid, ethane sulfonic acid, trifluoromethane sulfonic acid and para-toluene sulfonic acid, of which all are appropriate, the sulfonic acid being methane sulfonic acid.

5. The composition in the form of an aqueous compound consisting of at least one compound of the formula (1) as defined in one of Reputations 1 and 2 and at least one sulfonic acid as defined in one of Reputations 3 and 4, of which at least one sulfonic acid is appropriate, and more appropriate is MSA6.

7. Any component under Reputation 5 and 6 contains sulfonic acid from 0.01% to 100% by weight in combination with at least one corrosion inhibitor of Formula (1) under Reputation 1 and 2, generally from 0.05% to 90% by weight, specifically from 0.5% to 75% by weight in relation to the total weight of such component, in which the remaining component contains a solvent and / or diluent, preferably aqueous diluent and / or solvent, preferably water and, alternatively, one or more additives. 8.Any composition under any of the claims 5 through 7, consisting of at least one sulfonic acid selected from methanesulfonic acid, ethanesulfonic acid, normal-propanesulfonic acid, iso-propanesulfonic acid, normal-butanesulfonic acid, iso-butanesulfonic acid, sec-butanesulfonic acid, tert-butanesulfonic acid, trifluoromethanesulfonic acid, para-toluenesulfonic acid, benzenesulfonic acid, and two or more of them in any proportion, The ideal combination is methane sulfonic acid, in combination with at least one corrosion inhibitor compound of the formula O=N-OX, where X is chosen from H, NO, alkyl radical R, straight or branched chain containing 1 to 6 carbon atoms, and -SO2-G or -CO-G, which is a radical where G represents OH or R as defined above. The combination of sulfonic acid and corrosion inhibitor represents the total weight of all such components from 0.05% to 90% by weight, where the specific weight is from 0.5% to 75% by weight, with the remaining component being water.

10. Any component of claims 5 through 8, consisting of methane sulfonic acid, nitrosyl sulfuric acid, and water.

10. Any component of claims 5 through 9, also consisting of one or more additives selected from: • solvents, hydrotropic agents, or dissolving agents; • biocides, disinfectants (bromoacetic acid, peracetic acid, aqueous hydrogen peroxide, chlorine dioxide, chlorine, bromine, and similar); • flow agents, surface agents, viscosity agents, and viscosity enhancers. • Thickeners, gelling agents, • complexing agents; • organic or inorganic acids; • flame retardants; • preservatives; • anionic, cationic, non-ionic or amphoteric surfactants (e.g., ethoxylated, alkyl and / or aryl sulfonated alcohols and / or amines), emulsifiers, detergents, soaps and similar; • foaming agents, antifoaming agents; • antifreeze agents (e.g., ethylene glycol, propylene glycol and similar); • dyes, pigments; and • fragrances, odorizing agents.11.A process for protecting metals from corrosion by sulfonic acid, particularly metals and alloys which can be passivated, with the specific characteristic that the sulfonic acid in contact with the metal is one of the elements specified in Patents 5 to 1012. The process under Patent 11 in which the metal is selected is stainless steel or alloys based on iron or nickel, titanium, copper, aluminum, molybdenum, manganese, lead and their alloys and their counterparts (in the electrical sense).

13. The use of any of the elements under claims 5 through 10 for storage, catalytic or other reactions, cleaning, descaling, detergency, stripping, disinfection, galvanoplasty, plating and similar, at temperatures ranging from -10°C to 200°C, the optimal range being from 0°C to 160°C. 14.The use under claim 13 is for stripping, cleaning, descaling and rinsing of inorganic and / or organic contaminants in the food processing industries such as dairy products, cheese-making facilities, meat product and grocery packaging, beer, and also for stripping, cleaning and descaling of inorganic residues in cement work, in all domains where it is necessary and required to remove rust or in practice. The use of oil and gas where acid solutions are necessary for dissolving subsurface rocks, especially carbonate-based rocks.

15. The use under either claim 13 and 14 for limiting or even preventing corrosion of containers, barrels, tanks, receptacles, reactors, fermenters, lines, pipes, tubes, valves where at least one sulfonic acid is stored or transported.The use of at least one compound of the general formula(1):O=N-OX(1), where X is chosen from:H;NO; alkyl radical R, straight or branched chains containing 1 to 6 carbon atoms; aryl radical Ar, which is selectively replaced, specifically by at least one alkyl radical R;-SO2-G, which is radical in which G represents H,OH,R,OR,OM,Ar,OAr,NH2,NHR and NRR', where R and Ar are as defined above, R' represents alkyl radical, straight or branched chains containing 1 to 6 carbon atoms.

1. Using carbon from 1 to 6 atoms and M representing a monovalent or bivalent metal cation, appropriately a metal cation from alkali or alkaline earth metals; and -CO-G as a radical where G is as defined above, for limiting or even preventing corrosion of metals by sulfonic acids.

2. Using according to claim 1 where X represents -SO2-G, appropriately -SO2-G where G represents -OH or R, R representing alkyl radical, appropriately methyl radical. 3.The use under claim 1 or claim 2, in which sulfonic acid is the acid of the formula R-SO3H, where R represents a saturated, straight or branched hydrocarbon chain composed of 1 to 4 carbon atoms, which is, alternatively, replaced wholly or partially by one or more identical or different halogen atoms, or an aryl radical that is selectively replaced by a saturated, straight or branched hydrocarbon chain composed of 1 to 4 carbon atoms that is selectively replaced wholly or partially by one or more identical or different halogen atoms.4.Under any one of the preceding claims, in which sulfonic acid is selected from methane sulfonic acid, ethane sulfonic acid, n-propane sulfonic acid, iso-propane sulfonic acid, n-butane sulfonic acid, iso-butane sulfonic acid, sec-butane sulfonic acid, tert-butane sulfonic acid, trifluoromethane sulfonic acid, para-toluene sulfonic acid, benzene sulfonic acid and any two or more of them in any appropriate proportion, then the sulfonic acid is selected from methane sulfonic acid. Ethane sulfonic acid, trifluoromethane sulfonic acid and para-toluene sulfonic acid, all appropriately the sulfonic acid is methane sulfonic acid.

5. The composition in the form of an aqueous compound consisting of at least one compound of formula (1) as defined in one of Reputations 1 and 2 and at least one sulfonic acid as defined in one of Reputations 3 and 4, of which at least one alkane sulfonic acid is appropriate, more appropriately the MSA.6.The components under claim 5 in which the amount of compounds of formulation (1) is between 1 ppm and 10%, the optimal is between 5 ppm and 1000 ppm, and the more optimal is between 10 ppm and 800 ppm, by weight relative to the total weight of the components.

7. Any component under claim 5 and 6 that contains from 0.01% to 100% by weight of sulfonic acid in combination with at least one type of corrosion inhibitor of formulation (1) under claim 1 and 2, more generally from 0.05% to 90% by weight, the specific is from 0.5% to 75% by weight, relative to the total weight of such components, the remainder of the components that contain solvents and / or diluents, the optimal is aqueous diluent and / or solvent, the more optimal is water and, alternatively, one or more additives.8.Any of the components under Claims 5 through 7, which include at least one sulfonic acid selected from methane sulfonic acid, ethane sulfonic acid, n-propane sulfonic acid, iso-propane sulfonic acid, n-butane sulfonic acid, iso-butane sulfonic acid, sec-butane sulfonic acid, tert-butane sulfonic acid, trifluoromethane sulfonic acid, para-toluene sulfonic acid, benzene sulfonic acid and two or more of them in any proportion, with methane sulfonic acid being the appropriate component, in the Combined with at least one type of corrosion-inhibiting compound of the formula O=N-OX, where X is chosen from H, NO, alkyl radical R, straight or branched chains containing 1 to 6 carbon atoms, and -SO2-G or -CO-G which is radical, where G replaces OH or R as defined above, sulfonic acids, and the combination of corrosion inhibitors representing from 0.05% to 90% by weight, specifically from 0.5% to 75% by weight, of the total weight of such components, with the remainder being water.

10. Any one of the components of claims 5 through 8, consisting of methane sulfonic acid, nitrosyl sulfuric acid, and water.

10. Any one of the components of claims 5 through 9, also consisting of one or more additives selected from: solvents, hydrotropic agents or solubilizing agents, biocides, disinfectants (bromoacetic acid, peracetic acid, aqueous hydrogen peroxide, chlorine dioxide, chlorine, bromine and similar), flow agents, surface agents, Thickeners, gelling agents, complexing agents; organic or inorganic acids; flame retardants, preservatives, anionic, cationic, non-ionic or amphoteric surfactants (e.g., ethoxylated, alkyl and / or aryl sulfonated alcohols and / or amines), emulsifiers, detergents, soaps and similar products, foaming agents, antifoaming agents, antifreeze agents (e.g., ethylene glycol, propylene glycol and similar products), dyes, pigments; and fragrances, scenting agents.11.The process for protecting metals from corrosion by sulfonic acids, particularly metals and alloys that can be passivated, is characterized by the presence of sulfonic acids in contact with the metal being one of the elements specified in Patents 5 to 1012. The process under Patent 11 involves the selection of a metal of iron or nickel-based composition, stainless steel or its alloys, titanium, copper, aluminum, molybdenum, manganese, lead, and their alloys, and is also a dual process (in a 13. The use of any of the elements under claims 5 through 10 for storage, catalyst reactions or cleaning, descaling, detergency, stripping, disinfection, galvanoplasty, plating and similar, at temperatures ranging from 10°C to 200°C, preferably from 0°C to 160°C. 14.The use under claim 13 for the descaling, cleaning, scaling and rinsing of inorganic and / or organic contamination in the food processing industries such as dairy products, cheese-making facilities, meat product and grocery packaging, beer, and also for the descaling, cleaning and scaling of inorganic residues in cement work, in all domains where it is necessary and required to remove rust or in oil and gas operations where acid solutions are necessary to dissolve underground rocks, especially carbonate-based rocks.

15. The use under either claim 13 and 14 for limiting or even preventing corrosion of containers, barrels, tanks, supports, reactors, fermenters, lines, pipes, tubes, valves where at least one sulfonic acid is stored or transported.