VAPOR-PHASE ALKYLATION-LIQUID-PHASE TRANSALKYLATION

摘要

PROBLEM TO BE SOLVED: To use a polyalkylbenzene in a transalkylation reaction, by carrying out a vapor-phase alkylation in the presence of a specific zeolite catalyst under prescribed reaction conditions to give ethylbenzene and recovering the polyalkylbenzene prepared as a by-product. ;SOLUTION: A mixture of ethylene and benzene is supplied to a multi-stage alkylation reaction zone 2 equipped with plural beds which are connected in series and packed with a silicalite catalyst having ≥275 Si/Al ratio to carry out vapor-phase ethylation. In the ethylation, the space velocity of benzene supply is adjusted to a flow rate to make ≤ about 600 ppm xylene concentration in a reaction product, ≤0.25 wt.% of a polyalkylated benzene component heavier than diethylbenzene (based on ethylbenzene, respectively). After the separation of ethylbenzene, a polyalkylated benzene containing diethylbenzene is recovered and a part of the polyalkylated benzene and benzene are supplied to a transalkylation zone. The zone is operated under such conditions of temperature and pressure as to promote the disproportionation of the polyalkylated benzene, reduction in the content of diethylbenzene and increase in the content of ethylbenzene.;COPYRIGHT: (C)1998,JPO