Patent ID: 8552238

Claim:
A process for producing an alkylaromatic compound, the process comprising: (a) introducing an input stream comprising an aromatic hydrocarbon, and an alkylating agent comprising an alkene into a preliminary alkylation system comprising a preliminary alkylation catalyst having a first SiO 2 /Al 2 O 3 ratio, wherein said preliminary alkylation catalyst is a zeolite MCM-22 catalyst; (b) operating said preliminary alkylation system under alkylation conditions to produce said alkylaromatic compound, said conditions being such that said aromatic hydrocarbon is at least partly in the liquid phase; (c) withdrawing from said preliminary alkylation system a first output stream comprising said alkylaromatic compound, unreacted aromatic hydrocarbon, and about 100 ppb or less of catalyst poisons; (d) introducing at least part of said first output stream and an alkylating agent into a first alkylation system comprising a first alkylation catalyst having a second SiO 2 /Al 2 O 3 ratio, said first alkylation catalyst is a wherein the first alkylation catalyst is a zeolite MCM-22 catalyst; wherein the preliminary alkylation catalyst and the first alkylation catalyst are different in that the preliminary alkylation catalyst has a lower SiO 2 /Al 2 O 3 ratio than the first alkylation catalyst whereby the frequency at which any alkylation catalyst is removed for replacement, regeneration or reactivation is reduced as compared to either alkylation catalyst alone; (e) operating said first alkylation system under alkylation conditions to produce said alkylaromatic compound, said conditions being such that said aromatic hydrocarbon is at least partly in the liquid phase; and (f) withdrawing from said first alkylation system a second output stream comprising said alkylaromatic compound.