Patent ID: 6222084
Filing Date: 2001-04-24
Classification: C07C

Abstract:
A method for the alcylation of benzene, comprising the following steps:(a) supplying a feedstock containing benzene and ethylene to an alkylation reaction zone containing a pentasil molecular sieve aromatic alkylation catalyst comprising predominantly monoclinic silicalite having a silica/alumina ratio of at least 300 and an average crystal size of about 0.5 microns or less;(b) operating said alkylation reaction zone at temperature and pressure conditions under which benzene is in the gaseous phase to cause gas phase ethylation of said benzene in the presence of said silicalite catalyst to produce an alkylation product comprising a mixture of ethylbenzene and polyalkylated aromatic components including xylene and diethylbenzene;(c) supplying said feedstock to said reaction zone at a benzene/ethylene mole ratio within the range of 10-25 and under conditions in which a response of said silicalite catalyst to a decrease in the benzene/ethylene ratio of 20% produces a responsive increase in xylene of no more than 10% relative to the amount of ethylbenzene produced in the alkylation reaction zone; and(d) withdrawing said alkylation product from said reaction zone and separating and recovering of ethylbenzene from said alkylation product.