Abstract:

Different micro-mesoporous ZSM-5 molecular sieve were prepared from microporous ZSM-5 molecular sieve, which was treated by sodium hydroxide solution under various concentrations and processing times.Then, micro-mesoporous ZSM-5 molecular sieve catalyst was prepared by loading phosphorus pentoxide,and it was evaluated by alkylation reaction of toluene with methanol.It was found that the activity was higher for the P₂O₅ supported catalyst,which was prepared using micro-mesoporous ZSM-5 molecular sieve for 30 min alkali treatment under the sodium hydroxide solution of 1.0 mol/L.On this basis,platinum was further used to modify the micro-mesoporous ZSM-5 molecular sieve catalyst loaded by P₂O₅.The prepared catalyst was applied for the alkylation of toluene with methanol.For continuously 505 h reaction at 460 ℃,the conversion of toluene and the selectivity of p-xylene in xylene maintained 10.9% and 96%, respectively.The results showed that P₂O₅ and Pt modified micro-mesoporous ZSM-5 molecular sieve exhibited highly catalytic performance for alkylation of toluene with methanol.

Key words: alkali treatment, micro-mesoporous ZSM-5 molecular sieve, alkylation of toluene with methanol