锑改性纳米ZSM-5分子筛在苯和甲醇烷基化中的应用

Alkylation of Benzene with Methanol over Nano ZSM-5 Modified by Antimony Oxide

对比研究了微米和纳米ZSM-5分子筛催化苯和甲醇烷基化性能,采用XRD、SEM、NH 3-TPD、BET等手段表征制备的分子筛。结果表明:纳米ZSM-5分子筛晶粒更小、比表面积和孔体积更大、酸量更多,在苯和甲醇烷基化反应表现出更佳的催化性能和抗积碳能力。纳米ZSM-5分子筛经过锑改性,大部分锑物种覆盖在分子筛外表面,窄化了孔道,钝化了外表面酸性,用于苯和甲醇烷基化反应,苯的转化率下降,但甲苯、二甲苯选择性及对二甲苯选择性显著提升。

The catalytic performance in the methylation of benzene with methanol over micro and nano sized ZSM-5 were investigated comparatively,and XRD,SEM,NH 3-TPD and BET were applied to characterize the prepared zeolites.The results showed that nano sized ZSM-5 exhibited smaller crystalline grain,higher BET surface area and pore volume,and more acidity amount,it exhibited better catalytic performance and coke deposition resistance capacity in the alkylation of benzene with methanol.Most of the antimony oxide were distributed in the out surface of the nano sized ZSM-5 after stibium modification,the pore were narrowed and the activation sites in the out surface were passivated.The methylation of benzene with methanol were catalyzed by the antimony modified ZSM-5,a decreased conversion of benzene and increased selectivity of para-xylene were observed.