Patent ID: 7199275

Claim:
A process for alkylation of an aromatic hydrocarbon stream comprising impurities in which said impurities are removed in a pretreatment system having a first stage, a second stage located downstream of said first stage and a cycle length, said process comprising the steps of: (a) contacting the aromatic hydrocarbon stream with a first molecular sieve which is 13X in said first stage of said pretreatment system, to remove at least a portion of said impurities, to produce a partially treated aromatic hydrocarbon stream; (b) contacting said partially treated aromatic hydrocarbon stream with a second molecular sieve which is 4A in a second stage of said pretreatment system to remove substantially all of the remaining portion of said impurities, and to produce a fully treated aromatic hydrocarbon stream; and (c) contacting said fully treated aromatic hydrocarbon stream with an alkylating agent in the presence of an alkylation catalyst and under alkylation conditions, to produce an alkylated aromatic hydrocarbon stream; and wherein said cycle length of said pretreatment system is greater than said cycle length using said first stage of said pretreatment system alone or said second stage of said pretreatment system alone.