GB818369A - Mixtures of surface-active agents and compositions containing these mixtures, and a process for preparing said mixtures - Google Patents

Abstract

A mixture of alkyl aryl sulphonates and secondary alkyl sulphates is obtained by splitting an olefin mixture consisting wholly or mainly of C8/C9-C18 olefins, such as may be obtained from the vapour-phase cracking of paraffin waxes or refined heavy cycle oil, into a first fraction comprising C8/C9-C12\sB1 olefins and a second fraction comprising C13\sB1-C18 olefins, using the first fraction in the catalytic alkylation of an aryl compound, suitably benzene, sulphonating the product obtained, and then sulphating the second fraction, preferably using the sulphonated mixture of the first fraction as the sulphating agent. Thereafter the products are neutralized with caustic soda and the sulphation product is saponified to convert any dialkyl derivatives to sodium monoalkyl sulphates. The products may then be extracted with gasoline to remove any unreacted material and subjected to liquid phase desalting. Alternatively, the olefin fractions may be separately condensed and sulphonated, and sulphated, and the products subsequently mixed. It is preferred that final ratio of sulphonate to sulphate be about 65 : 35. The mixed products may be used in detergent compositions in conjunction with carbonates, phosphates, silicates, foam stabilizers, washing promotors, and bleaching agents. Specification 818,368 is referred to.ALSO:A mixture of alkylaryl sulphonates and secondary alkyl sulphates is obtained by splitting an olefin mixture consisting wholly or mainly of C8/C9-C18 olefins, such as may be obtained from the vapour phase cracking of paraffin waxes or refined heavy cycle oil, into a first fraction comprising C8/C9-C12\sB1 olefins and a second fraction comprising C13 \sB 1-C18 olefins, using the first fraction in the catalytic alkylation of an aryl compound, suitably benzene, using preferably hydrofluoric or sulphuric acid as catalyst, sulphonating the product obtained, preferably with excess oleum, and then sulphating the second fraction, preferably using the sulphonated mixture of the first fraction, suitably in an inert diluent such as aromaticfree gasoline as the sulphating agent. Thereafter the products are neutralized with e.g. caustic soda and the sulphation product is saponified to convert any dialkyl derivatives to sodium monoalkyl sulphates. The products may then be extracted with gasoline to remove any unreacted material and subjected to liquid phase desalting. Alternatively, the olefin fractions may be separately condensed and sulphonated, and sulphated, and the products subsequently mixed. In an example, a C8-18 olefin mixture, obtained by the vapour phase cracking of paraffins, is split by distillation into C8-12 and C13-18 fractions. The C8-12 fraction is used to alkylate benzene, in the presence of hydrofluoric acid as catalyst, using a benzene: olefin ratio of 10 : 1. The total hydrocarbon : catalyst ratio is 1 : 1 (vol.). After 30 minutes at 4 atmospheres pressure and room temperature the excess benzene and a small quantity of light and heavy ends are distilled off, to yield an alkylate having a sulphonatability not above 90 per cent. This alkylate is sulphonated at 55 DEG C. with 20 per cent oleum, the mol. ratio SO3 : alkylate being 3 : 1, after which the mixture is diluted with water to a sulphuric acid concentration of 65-75 per cent. The C13-18 fraction is sulphated with 98 per cent sulphuric acid and the alkylbenzene sulphonic acids added. The mixture is then neutralized with caustic soda and saponified to convert dialkyl sulphates into monoalkyl sulphates. Alcohol is added, unconverted material is extracted with gasoline, and the purified mixture is subjected to liquid-phase desalting. In another example, a C8-18 olefin mixture is split into C8-11 and C12-18 fractions, and the lower fraction is condensed with benzene and sulphonated as before, the mol. ratio SO3 : alkylate being 6.5 : 1. Towards the end of the sulphonation reaction the C12-18 fraction is added to the reaction mixture and directly sulphated thereby. Specification 818,368 is referred to.