GB564059A - Improvements in or relating to the alkylation of benzene - Google Patents

Abstract

<PICT:0564059/IV/1> Benzene is alkylated by passing a feed containing benzene and olefins into a reaction zone containing a catalyst of the Friedel Crafts' type, fresh catalyst being introduced, and reaction products, unreacted constituents, and catalyst overflowing into a settling zone wherein unreacted vaporized constituents are separated, scrubbed with polyalkyl derivatives of benzene and the olefins to remove benzene, and the solution of benzene in said polyalkyl derivatives separated and recycled to the reaction zone. The feed may be benzene and an ethylenic gas containing ethane which react in the presence of aluminium chloride at about 160 DEG F. to yield ethyl benzene. A feed containing benzene and olefins together if desired with hydrogen chloride, is led by line 2 to reaction tower 1 containing aluminium chloride. Reaction products and catalyst flow by conduit 5 to settler 6 whence catalyst can be recycled by lines 8, 9, gases leave by line 7, and liquid products pass through receiver 11 to still 13 where unreacted aromatics are separated and may be recycled by line 19, while alkylated products pass to still 16 where the desired product, e.g. monoethyl benzene, is removed by line 17, and heavier constituents, e.g. polyethyl benzenes, leave by line 18 for recycling or discharge. The gases leaving by line 7 contain benzene vapours which are washed out in packed tower 25 by polyethyl benzenes introduced by line 21, the solution then being recycled by lines 23, 19 to reactor 1. The content of absorbed benzene should not exceed about 10 per cent.