High silica content zeolite-based catalyst

摘要

A high silica content zeolite-based catalyst for use in a reaction which uses a feedstock containing an aromatic hydrocarbon or which gives a product containing an aromatic hydrocarbon, which catalyst satisfies the following requirements (1), (2), (3) and (4): (1) the zeolite constituting a zeolite-based catalyst has an SiO₂/Al₂O₃ molar ratio of from 20 to 200; (2) the zeolite constituting a zeolite-based catalyst has a primary particle diameter of from 0.3 to 3 &mgr;m; (3) when a zeolite-based catalyst is converted into H type, the H type zeolite-based catalyst has a ratio of the number of surface acid sites to the total number of acid sites is from 0.03 to 0.15; and (4) a zeolite-based catalyst exhibits a pyridine-desorbed amount (B) as measured at a temperature of from 500° C. to 900° C. by a hot desorption method when converted into H type after being subjected to a steam treatment at an H₂O partial pressure of 0.8 atm and a temperature of 650° C. for 5 hours, and a pyridine-desorbed amount (A) as measured at a temperature of from 500° C. to 900° C. by a hot desorption method when converted into H type without the steam treatment, which amounts satisfy the following requirements:; $PTEXTPDAT\&agr;\≦/PDATHILBOLDPDAT1.6/PDAT/BOLD/HIL/PTEXT$ ; $\mathop{\mathrm{image}}$ \mathrm{\α}=\left(\frac{1}{B^2}-\frac{1}{A^2}\right)\÷5\×{10}^5.$$