GB420636A - Improvements in or relating to the production of alkyl derivatives of phenolic compounds - Google Patents

Abstract

An alkyl derivative of a phenolic compound is prepared by treating an olefine mixture with sufficient absorbing acid to absorb selectively the olefine which is to be reacted, the acid liquor being separated and treated with the phenolic compound in substantial excess of the theoretical proportion, the acid being removed by subsidence from the mixture which still contains sufficient acid to catalyze the reaction and is refluxed to give the desired derivative. An excess of 15--100 per cent for example 25 per cent by weight of phenol is preferred. The excess may be added in stages, the amount added to the acid liquor being 3--10 per cent more than the theoretical, and a quantity equal to 10--65 per cent of that originally theoretically required being added after separation of acid but before refluxing. A small amount of the phenol may be added to the residue produced by the fractional distillation which on re-distillation gives a further yield of the alkyl derivative. According to examples: (1) 62 per cent sulphuric acid is used to absorb iso-amylene by successive counter-current treatment with amylene-containing mixtures of progressively greater iso-amylene content. The acid liquor is agitated for 1 hour with phenol equivalent to 75 per cent excess of the molecular proportion, allowed to settle, and the oily layer refluxed for 4 hours at 130--135 DEG C., washed with water, and neutralized with soda ash. The product is distilled at 20 m.m. up to 139 DEG C., the portion boiling between 139 and 155 DEG C. and preponderating in the desired tertiary amyl phenol being collected separately. (2) Acid liquor obtained as in (1) is treated with phenol equivalent to 6,8 per cent excess. After removal of the acid, additional phenol is added and the material treated as in (1). (3) Distillation residues of Examples (1) and (2) were treated with 940 lbs. of phenol to 2340 lbs. of residue and again distilled as in (1). The invention is especially applicable to the condensation of phenol with olefine material containing from 2 to 10 carbon atoms.