改性介微孔ZSM-5分子筛催化剂制备及催化甲苯甲醇烷基化反应性能

将微孔ZSM-5分子筛通过不同浓度的氢氧化钠溶液处理不同的时间制备不同的介微孔ZSM-5分子筛,然后负载五氧化二磷制备介微孔ZSM-5分子筛催化剂,对介微孔ZSM-5分子筛负载五氧化二磷催化剂进行甲苯甲醇烷基化反应评价。其中氢氧化钠溶液浓度为1.0 mol/L、处理时间为30 min得到的介微孔ZSM-5分子筛负载五氧化二磷催化剂催化甲苯甲醇烷基化反应的活性较高。对介微孔ZSM-5分子筛负载五氧化二磷催化剂进一步采用铂进行改性,将制备的催化剂用于甲苯甲醇烷基化反应,在460 ℃条件下连续反应505 h,甲苯转化率保持在10.9%,二甲苯中对二甲苯的选择性保持在96%以上。研究结果表明,五氧化二磷、铂改性的介微孔ZSM-5分子筛催化剂具有优异的甲苯甲醇烷基化反应性能。

Preparation of modificated micro-mesoporous ZSM-5 molecular sieve catalyst and its catalytic performance for alkylation of toluene with methanol

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.