GB818367A - Mixtures of surface-active agents and compositions containing these mixtures - Google Patents

Abstract

A detergent mixture comprises (a) alkyl aryl sulphonates having 8 and/or 9 carbon atoms in the alkyl groups, preferably together with one or more alkyl aryl sulphonates with 10-13 carbon atoms in the alkyl groups, but substantially free from alkyl aryl sulphonates with less than 8 or more than 13 carbon atoms in the alkyl groups and (b) a mixture of secondary alkyl sulphates containing each member of the series having 8 or 9-18 carbon atoms, the relative proportions of (b) to (a) being 60 : 20 to 40 : 80 respectively. The mixture may suitably be prepared by (i) the catalytic alkylation of an aromatic hydrocarbon using hydrofluoric or sulphuric acid as catalyst, and using as the alkylating agent an olefin mixture obtained by the vapour phase cracking of paraffin waxes, by cracking refined catalytically cracked heavy oil, or by the polymerization of lower alkenes; (ii) sulphonating the alkylates so obtained with excess oleum; (iii) using the resulting mixture as the sulphating mixture for a mixture of olefins containing each member of the series having 8 or 9-18 carbon atoms, preferably in the presence of an inert diluent such as aromatic-free gasoline; (iv) neutralizing the resulting mixture with aqueous caustic soda and saponifying to convert the dialkyl sulphates to mono-alkyl sulphates; (v) desalting the mixture, and (vi) removing unconverted organic material by extraction with gasoline. Alternatively the alky aryl sulphonates and alkyl sulphates may be prepared separately and then mixed. Alkyl phenol polyoxyethylene ethers, preferably those with 7-9 carbon atoms in the alkyl chain and 8-10 ethylene oxide residues per molecule, are desirably incorporated in the mixture to the extent of 10-20 per cent of the total surfaceactive material present. The compositions may also include other detergents, phosphates, silicates, carbonates, foam stabilizers, washing promoters and bleaching agents. Specification 818,368 is referred to.ALSO:A detergent mixture comprising (a) alkyl aryl sulphonates having 8 and/or 9 carbon atoms in the alkyl groups, preferably together with one or more alkyl aryl sulphonates with 10-13 carbon atoms in the alkyl groups, but substantially free from alkyl aryl sulphonates with less than 8 or more than 13 carbon atoms in the alkyl groups; and (b) a mixture of secondary alkyl sulphates containing each member of the series having 8 or 9-18 carbon atoms, the relative proportions of (b) to (a) being 60 : 20 to 40 : 80 respectively, may be prepared by (i) the catalytic alkylation of an aromatic hydrocarbon suitably benzene, using hydrofluoric or sulphuric acid as catalyst, and using as the alkylating agent an olefin mixture obtained by the vapour phase cracking of paraffin waxes, by cracking refined catalytically cracked heavy oil, or by the polymerization of lower alkenes; (ii) sulphonating the alkylates so obtained with excess oleum; (iii) using the resulting mixture as the sulphating mixture for a mixture of olefins containing each member of the series having 8 or 9-18 carbon atoms, preferably in the presence of an inert diluent such as aromatic-free gasoline; (iv) neutralizing the resulting mixture with aqueous caustic soda and saponifying to convert the dialkyl sulphates to monoalkyl sulphates; (v) desalting the mixture; and (vi) removing unconverted organic material by extraction with gasoline. Alternatively the alkyl aryl sulphonates and alkyl sulphates may be prepared separately and then mixed. According to Example II, benzene is catalytically alkylated in the presence of hydrofluoric acid in a stirred reactor with a C9-13 olefin mixture obtained by the vapour phase cracking of a catalytically cracked refined heavy hydrocarbon oil, the ratio of benzene: olefins being 10 : 1 and the volume ratio of hydrocarbons to hydrofluoric acid being 1 : 1. The residence time in the reactor is 30 minutes at room temperature, stirring being at the rate of 220 r.p.m. and the pressure being 4 atmospheres absolute. After alkylation the excess benzene is distilled off at atmospheric pressure, and a small quantity of light and heavy ends is then removed at 40 mm. to leave an alkylate having a sulphonatability not exceeding 90 per cent. This alkylate is sulphonated at 55 DEG C. with oleum containing 23 per cent by weight free SO3, the mol. ratio of SO3: alkylate being initially 6.3: 1. Towards the end of the sulphonation reaction a quantity of C9-18 olefins is added and thereby sulphated, the quantity added being such that the resulting mixture contains 40 parts by weight alkylbenzene sulphonic acids and 60 parts alkyl sulphuric acids. This mixture is then neutralized and saponified with caustic soda solution to convert the dialkyl sulphates present to mono-alkyl sulphates, after which 25 per cent isopropyl alcohol is added to desalt the composition. Unconverted organic material is then removed by extraction with gasoline and the solution finally concentrated by evaporation. Specification 818,368 is referred to.