Patent ID: 6872864

Claim:
A method for controlling a process for producing a monoalkyl aromatic, said method comprising: a) passing an aromatic feed stream comprising a feed aromatic and an olefinic feed stream comprising an olefin to an alkylation catalyst bed in an alkylation reaction zone, wherein said alkylation catalyst bed contains a solid crystal line catalyst and wherein the ratio of the weight of said olefin entering said alkylation catalyst bed in said olefinic feed stream per unit time to the sum of the weight; of compounds entering said alkylation catalyst bed per said unit time, multiplied by 100, is less than 1.88, wherein said solid crystalline catalyst comprises a zeclite selected from the group consisting of zeolite beta, ZSM-5, PSH-3, MCM-22, MCM-36, MCM-49, MCM-56, mordenite, and omega; b) alkylating said feed aromatic with said olefin in said alkylation catalyst bed at alkylation conditions and in the presence of said solid crystalline catalyst to form a monoalkyl aromatic, wherein said monoalkyl aromatic has one more alkyl group corresponding to said olefin than said feed aromatic; c) withdrawing an effluent stream from said alkylation reaction zone, wherein said effluent stream comprises said monoalkyl aromatic and has a content of diarylalkane of less than 1.0 wt-% diarylalkane relative to said monoalkyl aromatic; d) measuring said content of diarylalkane in said effluent stream; e) adjusting the ratio of the weight of olefin entering the process to the sum of the weights of compounds entering the process based on said content of diarylalkane; and f) recovering said monoalkyl aromatic from said effluent stream.