| 摘要 |
PURPOSE: Provided is a process for the selective production of para-xylene by catalytic methylation of toluene in the presence of a solid catalyst. Also provided is a method for preparing a catalyst which is particularly suited for this reaction. CONSTITUTION: A process for the selective production of para-xylene comprises reacting toluene with methanol in the presence of a catalyst comprising a porous crystalline material having a Diffusion Parameter for 2,2 dimethylbutane of about 0.1-15 per sec. when measured at a temperature of 120°C and a 2,2 dimethylbutane pressure of 60 torr (8kPa). The porous crystalline material is preferably a medium-pore zeolite, particularly ZSM-5, which has been severely steamed at a temperature of at least 950°C. The porous crystalline material is preferably combined with at least one oxide modifier, preferably including phosphorus, to control reduction of the micropore volume of the material during the steaming step. |
