GB693390A - Process for preparing branched chain primary sulfate esters - Google Patents

Abstract

Branched chain primary alkyl sulphates are obtained by reacting ethylene with a tertiary olefin in the presence of 80-100 weight per cent sulphuric acid at a temperature of -25 DEG C. to +80 DEG C. and at an ethylene partial pressure of 50-1000 p.s.i.g. The tertiary olefin may be aliphatic or alicyclic and may range from C4 to C30 or higher. The molar ratio of ethylene to tertiary olefine should preferably be greater than 50 : 1 but lower ratios may be employed when a tertiary olefine such as tetraisobutylene where the rate of self polymerization is negligible is employed. The reaction is preferably effected by adding the tertiary olefin to thn reactor containing the sulphuric acid and ethylene under the desired pressure and an inert hydrocarbon diluent is preferably employed. The diluent may be a saturated aliphatic or alicyclic hydrocarbon preferably a normal or iso-paraffin and when a branched chain hydrocarbon is employed as diluent it should preferably have the same carbon skeleton structure as the tertiary olefine. In a continuous type operation the tertiary olefine may be fed at the bottom of a reactor containing the sulphuric acid intermixed with the inert diluent and continuously withdrawing the tertiary olefine-free diluent from the top of the reactor. The primary sulphates produced by the process may be hydrolysed with water to give branched chain primary alcohols. Examples are given in which (1) isobutylene is reacted with ethylene using 95.5 weight per cent sulphuric acid at -15 DEG C. using n-heptane as p diluent to yield a primary sulphate ester which on hydrolysis with water yields 3,3-dimethyl-butanol-1; (2) a mixture of 2-methyl pentene-2 and 2-methylpentene-1 is similarly reacted with ethylene to give 3,3-dimethyl-hexanol-1; (3) a mixture of hexenes in which the ratio of tertiary/secondary olefins is about 3.5 : 1 yields hexyl ethanols, and (4) 1-methylcyclopentene yields a 2-alkylated ethanol in which the branching is an alicyclic radical. A Table is also given in which the production of various alkylated ethanols from the corresponding tertiary olefine and ethylene using 95-96 per cent sulphuric acid is described. The primary sulphate esters may be reacted with hydrogen halides such as HI, HBr2, HCl, HF to yield the corresponding halide, the reaction being effected by treating the primary sulphate ester with anhydrous hydrogen halide at 0 DEG to 100 DEG C. and preferably at 25 DEG to 50 DEG C. The primary sulphate esters also react with ammonia to form primary amines and on alcoholysis form other esters and mixed neutral sulphates whilst on heating the acid sulphate esters decompose to form alpha olefines. It is stated that the acetate derived from 3,3-dimethylbutanol and glacial acetic acid is useful as a lacquer solvent and that the di-octyl phthalate ester derived from phthalic anhydride and the branched chain alcohol of the invention can be employed as a plasticizer for polyvinyl chloride-type plastics.