Preparation of alkylated aromatics

摘要

Aromatic conversion processes and catalysts useful therein and their preparation including alkylation and transalkylation processes involving alkylation of an aromatic substrate with a C2-C4 alkylating agent with recovery of a monoalkylated aromatic product and liquid phase transalkylation of a polyalkylated product. Specifically, a benzene feedstock is supplied to an alkylation zone operated under liquid or vapor phase conditions with the output supplied to the transalkylation zone operated under lower temperature liquid phase conditions. In aromatic conversion processes over molecular sieve catalysts such as zeolite Y or beta under liquid phase conditions, an aromatic feedstock containing water is passed to a dehydration zone to provide a dehydrated feedstock of a water content of no more than 100 ppm, preferably 50 ppm or less. A specific molecular sieve catalyst comprises hydrogen zeolite beta of high surface area and low sodium content. The modified zeolite beta has a surface area of at least 600 m<2>/g and a sodium content of less than 0.04 wt.% Na2O. The modified zeolite beta is prepared from as-synthesized zeolite beta by sequential ion exchange treatments with intermediate calcination at a temperature of 400 DEG -700 DEG C for a period of two hours or longer.