GB1049828A - Sulphating alpha-olefins - Google Patents

Abstract

A laundering composition comprises 2-tetradecyl sodium sulphate, mixed with three times its weight of sodium tripolyphosphate (see Example I).ALSO:<PICT:1049828/C2/1> A process for manufacturing sulphated olefines comprises (A) reacting with agitation from 1.5 to 4 moles of H2SO4 of 94.5-100% by weight concentration and 1 mole of an a -olefine containing 9-24 C atoms in the presence of a nonionic organic crystallization medium which is inert to H2SO4 and the a -olefine, said medium being in liquid form and present in amount from 0.5-4 times the weight of the a -olefine and which amount is sufficient to maintain a fluid reaction mixture, said medium also being in a physical state of boiling under reflux to control the reaction temperature, the temperature of boiling being within the shaded area of Fig. 2 of the accompanying drawing, the proportions of reactants to medium being such that prompt crystallization is effected of 2-carbon secondary alkyl sulphuric acid as it is formed; (B) continuing the agitation under the conditions specified in (A) until reaction and crystallization are substantially complete, and (C) neutralizing the secondary alkyl sulphuric acid crystals so formed directly from their crystalline state to a pH above 8 by addition of a base to produce a 2-carbon secondary alkyl sulphate. The process may be batch or continuous; Fig. 1 (not shown), shows suitable apparatus for the latter procedure. Fig. 2 shows how the M.W. of the starting a -olefine affects the range of crystallization temperature of the secondary alkyl sulphuric acid products. Preferred conditions in order to keep on line A of Fig. 2 are an H2SO4 concentration of 97.4\sB0.3% by weight, an H2SO4 : a -olefine mole ratio of 2.1-2.2:1, and a weight of ratio of crystallization medium to a -olefine of 1:1. Preferred embodiments are the use of a -olefines with 12-18 C atoms having straight chains, and a recrystallization medium that is a C3-C5 alkane, or a halogenated ethane or methane, or mixtures of these. Detail is given of how pressure, temperature, and concentration all affect the reaction to assist or prevent crystallization. This latter may be invoked by a seeding process, wherein crystals of secondary alkyl sulphuric acid are added to the reacting ingredients. The products have application as detergents (see Division C5).