GB751395A - Compositions containing tarnish inhibitors - Google Patents

Abstract

To reduce the tendency of aqueous detergent solutions, to tarnish certain metals or alloys, e.g. copper and nickel alloys, there is included in the solutions a hydroxamic acid of the formula RC(O)NHOH or the tautomeric formula RC(OH) : NOH, where R is an aliphatic hydrocarbon radical of 7-17 carbon atoms, which may be substituted. Salts of these acids, e.g. the sodium, pottasium, ammonium, barium, calcium or magnesium salts, may also be used. Specified compounds are caprylyl hydroxamic acid, capryl hydroxamic acid, potassium palmityl hydroxamate, potassium myristyl hydroxamate, potassium stearyl hydroxamate, and lauryl hydroxamic acid and its potassium salt. The proportion of hydroxamic compound may be 0.1-5 per cent, based on the detergent composition. The detergent solutions may contain (1) condensed phosphates, e.g. pentasodium or pentapotassium tripolyphosphate, tetrasodium or tetrapotassium pyrophosphate or sodium or potassium hexametaphosphate, and/or (2) anionic organic soapless detergents, e.g. alkylaryl sulphonates such as dodecylbenzene sulphonates or kerylnaphthalene sulphonates, alkyl sulphates such as sodium lauryl sulphate, sulphuric esters of monoglycerides or substituted alkyl sulphonates such as sodium palmityl methyltauride, and/or (3) non-ionic detergents, such as the condensation products of alkylphenols or mercaptans with ethylene oxide. Other ingredients which may be present are alkali sulphates, chlorides, silicates, borates, carbonates or orthophosphates, starch, salts of carboxymethyl cellulose, and fluorescent whitening agents. Cationic detergents should not be included. Specific compositions are formulated.ALSO:To reduce the tendency of aqueous solutions to tarnish certain metals or alloys, e.g. copper and nickel alloys, there is included in the solutions a hydroxamic acid of the formula RC(O) NHOH or the tautomeric formula RC(OH): NOH, where R is an aliphatic hydrocarbon radical of 7-17 carbon atoms, which may be substituted. Salts of these acids, e.g. the sodium, potassium, ammonium, barium, calcium, or magnesium salts, may also be used. Specified compounds are caprylyl hydroxamic acid, caprylhydroxamic acid, potassium palmityl hydroxamate, potassium myristyl hydroxamate, potassium stearyl hydroxamate, and lauryl hydroxamic acid and its potassium salt. The proportion of hydroxamic compound may be 0,1-5 per cent, based on the solute in the solution. The solutions may be detergent solutions and these may contain (1) condensed phosphates, e.g. pentasodium or pentapotassium tripolyphosphate, tetrasodium or tetrapotassium pyrophosphate or sodium or potassium hexametaphosphate, and (or) (2) anionic organic soapless detergents, e.g. alkylaryl sulphonates such as dodecylbenzene sulphonates or kerylnaphthalene sulphonates, alkyl sulphates such as sodium lauryl sulphate, sulphuric esters of monoglycerides or substituted alkyl sulphonates such as sodium palmityl methyltauride, and (or) (3) non-ionic detergents, such as the condensation products of alkylphenols or mercaptans with ethylene oxide. Other ingredients which may be present are alkali sulphates, chlorides, silicates, borates, carbonates, or orthophosphates, starch, salts of carboxymethyl cellulose, and fluorescent whitening agents. Cationic detergents should not be included. Specific compositions are formulated.