GB600775A - Corrosion protective compositions - Google Patents

Abstract

A coating material for protecting metal surfaces against corrosion, and which may also be suitable as a lubricating composition for internal-combustion engines, comprises a substantially neutral vehicle wholly or mainly consisting of one or more hydrocarbons containing, finely dispersed, a corrosion-retarding amount of an organic compound, having a minimum of about 10 carbon atoms in the molecule, of the general formula <FORM:0600775/III/1> in which X is a radicle containing an acidic hydrogen atom, Y is a nitrile, nitro or nitrous radicle, R1 and R11 (which may be the same or different) are hydrogen atoms, or hydrocarbon or substituted hydrocarbon radicles, R is a hydrocarbon or substituted hydrocarbon radicle which may contain an ether type linkage with one oxygen, sulphur, selenium or tellurium atom in it, and n is 0, 1, 2 or 3. In the case where Y is a nitroso radicle, since compounds containing the group <FORM:0600775/III/2> may be found in equilibrium with those containing the isomeric form <FORM:0600775/III/3> , the general formula also embraces these isomeric compounds. Examples of vehicles which may be employed are liquid butanes, pentanes, hexanes, heptanes, octanes, benzene, toluene, xylenes, cumene, tetraline, indene, hydrindene, alkyl naphthalenes, gasoline distillates, kerosene, gas oil, lubricating oils (which may be soap-thickened to form greases), petrolatum, paraffin wax and albino asphalt. In vehicles of low dielectric constant, small proportions of carboxylic acids such as fatty or naphthenic acids may be present. The coating material may also contain resinous materials such as asphaltenes, petroleum resins, rosin or other natural resins, resins formed by the polymerization of drying fatty oils, phenol-formaldehyde resins or glyptal resins. It may also contain oil-soluble dicarboxylic acids or hydroxy aromatic carboxylic acids possessing corrosion protective properties, namely those having at least 12 carbon atoms in the molecule. Such acids may contain substituent radicles such as hydroxyl, ether, amino, nitro, hydrosulphide, sulphide and halide. When the coating material is employed as a lubricating oil for internal-combustion engines, other additives may also be present, such as blooming agents, pour point depressants, viscosity improvers, anti-oxidants, extreme pressure agents, detergents and anti-foaming agents. Suitable detergents include the oil-soluble salts of metallic or organic bases with detergent-forming acids. Examples of such acids are fatty acids including those produced by the oxidation of paraffin wax, aromatic carboxylic acids and various substitution products of such acids, phenols and phenol sulphides, aromatic or petroleum sulphonic acids, sulphuric acid mono-esters, phosphoric, arsonic and antimony acid mono-and di-esters, thio-phosphoric, -arsonic and -antimony acids, and phosphoric and arsonic acids. Specific detergents of these types are mentioned. Suitable non-metallic detergents include phosphatides such as lecithin, fatty oils such as rape seed oil and voltolized fatty mineral oils. Specific anti-oxidants of the alkyl phenol, amino-phenol, amine, sulphurized compound and methylene bis-phenyl sulphide types are mentioned. Other corrosion inhibitors may also be present, such as alkali metal and alkaline earth salts of sulphonic acids and fatty acids. In examples, mineral lubricating oil compositions are described containing alpha-cyano-stearic acid, with or without alkyl succinic acids obtained by condensing maleic acid anhydride with olefins or olefin mixtures as described in U.S.A. Specification 2,133,734, and 2.6-ditertiary butyl phenol. For comparison purposes, a mineral lubricating oil composition containing only the alkyl succinic acids is described. The Specification as open to inspection under Sect. 91 refers to a substantially neutral vehicle containing finely dispersed a corrosion retarding amount of an acidic organic compound having a minimum of about 10 carbon atoms and containing a nitrile, nitro or nitroso radicle not more than four carbon atoms removed from an acidic radicle. Both polar and non-polar vehicles may be employed. Among the former are water, alcohols, phenols, ketones, keto alcohols, ethers, esters such as carboxylates, phosphates, phosphites, thiophosphates or carbonates, natural waxes, fats or fatty oils and weak nitrogenous bases. Numerous examples of these types of polar vehicles are given. Among the vehicles of little or no polarity are included carbon tetrachloride, ethylene dichloride, propyl chloride, butyl chloride, chlorbenzol, chlorinated kerosene and chlorinated paraffin wax. This subject-matter does not appear in the Specification as accepted.ALSO:A coating material for protecting metal surfaces against corrosion comprises a substantially neutral vehicle containing, finely dispersed, an organic compound, having a minimum of about 10 carbon atoms in the molecule, of the general formula <FORM:0600775/IV(b)/1> in which X is a carboxyl group, Y is a nitrile group, R1 and R11 (which may be the same or different) are hydrogen atoms, or hydrocarbon or substituted hydrocarbon radicles, R is a hydrocarbon or substituted hydrocarbon radicle which may contain an ether type linkage with one oxygen, sulphur, selenium or tellurium atom in it, and n is 0, 1, 2 or 3. Examples of suitable hydrocarbon radicles R, R1 or R11 are methyl, ethyl, propyl, isopropyl, normal, secondary or tertiary butyl, isobutyl, normal or secondary pentyl, isopentyl, hexyl, normal octyl, iso-octyl, normal decyl, isodecyl, dodecyl, tetradecyl, cetyl, stearyl, trimethyl octodecyl, allyl, methallyl, crotyl, methyl vinyl carbinyl, butenyl, pentenyl, hexenyl, propargyl, geranyl, oleyl, phenyl, naphthyl, anthryl, tolyl, xylyl, secondary butyl-naphthyl, dipropyl-naphthyl, benzyl, naphthyl - butyl, phenethyl, vinyl-phenyl, crotonyl-naphthyl, methallyl-phenyl, naphthyl-allyl, 2-phenyl-ethenyl, phenyl vinyl carbinyl, cinnamyl, ethyl-cyclohexyl, tributyl-cyclohexyl, cyclopentenyl, cyclohexenyl and vinyl cyclohexenyl. Suitable compounds may be produced: (1) by reacting a substituted bromacetic acid ester, wherein the radicle R is both the substituent and the esterifying radicle, with alcoholic potassium cyanide to convert it to the corresponding nitrilacetic acid ester, replacing the esterifying radicle by potassium through treatment with caustic potash and then converting the potassium salt to the free acid by hydrolysis; (2) by reacting ethyl nitrilacetate with sodium ethylate to produce a sodium substituted ethyl nitrilacetate, reacting this with the bromide of the radicle R to produce an ethyl nitrilacetate substituted with the radicle R and hydrolysing this to the free acid; (3) by reacting nitrile R1CH2CN with ketone (RO)2CO and metal alcoholate MOR to give a nitrilacetic acid ester substituted with radicle R1 and metal M and having radicle R as esterifying group and then acidifying to produce nitrilacetic acid substituted with radicle R1; (4) by condensing ketone R2CO with ethyl nitrilacetate to give an ethyl nitrilacetate substituted with the group R2C=, hydrogenating this by treatment with aluminium-mercury couple to produce the corresponding saturated compound and then obtaining the free acid by hydrolysis of the ester group; (5) by reacting an ethyl malonate having the radicle R and sodium as substituents with a methyl bromide having the radicle R1 and a nitrile group as substituents, to eliminate sodium bromide and then obtaining the free nitrile acid by hydrolysis of the two ester groups and decarboxylation of one carboxyl group; (6) by reacting an ethyl bromacetate having the radicle R as substituent with the nitrile R1CH2CN in presence of sodium ethylate to produce an ethane substituted with radicles R and R1 and the nitrile and esterified carboxyl groups and then removing the esterifying ethyl group by hydrolysis and (7) by reacting the unsaturated acid RCH=CHCOOH with hydrocyanic acid to give the saturated nitrile acid. Monocarboxylic acids suitable as starting materials for the preparation of the compounds by these methods include fatty acids such as decylic, undecylic, lauric, myristic, palmitic, stearic, arachic, behenic, oleic, phenyl acetic, phenyl propionic, phenyl lauric, phenyl palmitic, phenyl stearic, tolyl stearic, naphthyl acetic and naphthyl stearic acids. Naphthenic acids obtained from petroleum oils may also be used as well as synthetic naphthenic acids such as cyclohexyl acetic cyclohexyl propionic and cyclohexyl stearic acids, or the corresponding alkyl cyclohexyl, tetrallyl or dicyclohexyl fatty acids, or acids derived from naphthenes obtained by hydrogenation of isophorone, diisophorone and homologues. Hydroxy acids such as hydroxybenzoic and hydroxy naphthenic acids and the alkyl homologues thereof, particularly the salicylic acids, may also be employed.