GB1036589A - Production of ethylbenzene - Google Patents

Abstract

Ethylbenzene is produced by reacting benzene with a gas containing not more than 60% volume of ethylene together with an inert gas under conditions such that all the ethylene is reacted in the presence of aluminium chloride and a promoter, withdrawing liquid, separating catalyst complex which is returned to the reactor, processing the remaining liquid to remove acidic materials and separate overhead benzene, which is recycled to the reactor, from a first bottoms fraction which is distilled to recover an ethylbenzene overhead fraction as product and a second bottoms fraction further distilled to recover a polyethylbenzene overhead fraction which is eventually recycled to the reactor and continuously removing from the reactor inert gas containing benzene, whereby heat of reaction is absorbed, the gas is chilled to separate some benzene which is recycled to the reactor and scrubbed first with a portion derived from the first bottoms fraction to absorb aromatics, the resulting liquor being recycled to the process, and then with a polyethylbenzene material. Preferably the gas is first contacted with ethylbenzene, e.g. an intermediate fraction or bottoms from the benzene column or an intermediate fraction or overhead from the ethylbenzene column. The resultant liquor is recycled to the acid removal step which may comprise water and caustic washes. In the second scrubbing the gas is treated with polyethylbenzene, e.g. overhead from the polyethylbenzene column, and the liquor is recycled to the reactor. Scrubbing liquid may be cooled before or during the scrubbing. Alkylation may be effected at 85-105 DEG C. and 1-130 atmospheres using an ethyl group to phenyl group ratio of 0.4-0.6. The promoter may be hydrogen chloride or ethyl chloride.