采用水热晶化法,通过改变水量来调节初始凝胶浓度,在Na2O∶H2O∶四丙基溴化铵∶SiO2摩尔比为0.07∶x∶0.05∶1.00(x分别为5.00,15.00,25.00,35.00,对应的试样依次命名为试样1～试样4)下,合成了一系列多级孔ZSM-5分子筛.以此为基质,制备了用于甲醇转化制丙烯(MTP)反应的HZSM-5分子筛催化剂,并在连续流动固定床微反装置上,于甲醇空速为9.78 h-1,反应温度为450℃,反应时间为120 min及常压条件下,考察了分子筛催化剂的活性.结果表明:体系水量的改变对ZSM-5分子筛的骨架结构无明显影响;与传统微孔ZSM-5分子筛催化剂(试样4)相比,多级孔分子筛催化剂(试样1 ～试样3)因具有较好的传质特性和较大的比表面积,提高了催化剂活性、稳定性及丙烯收率;在多级孔分子筛催化剂(以试样2为基质)运行120 min内,转化率、丙烯收率和丙烯/乙烯(质量比)基本不变,依次约为100％,32％,7.5.%A series of hierarchical ZSM-5 zeolites were synthesized by traditional hydrothermal crystallization method and changing water content for regulating the concentration of initial gel at the mole ratio of Na2O∶ H2O∶ TPABr∶ SiO2 of 0.07∶ x∶ 0.05∶1.00 (x =5,15,25,35,the samples were according named as sample 1 to sample 4).The as-synthesized ZSM-5 zeolites were used as base to prepare acid HZSM-5 zeolite catalysts.Methanol to propylene(MTP) catalysis properties were evaluated in a continuous flow fixed-bed microreactor under the conditions of atmospheric pressure,reaction temperature 450 ℃,reaction time 120 min,volume space velocity 9.78 h-1.The results showed that the change of water content had no obvious effect on skeleton structure of ZSM-5.Compared with traditional microporous ZSM-5 zeolite (sample 4),hierarchical ZSM-5 zeolite (sample 1-sample 3) with the better mass transfer property and the bigger surface area enhanced the activity stability of catalysts and the propylene yield.When hierarchical ZSM-5 zeolite based catalysts (sample 2 as the matrix)had been running for 120 min,the methanol conversion,propylene yield and propylene/ethylene(mass ratio) was 100％,32％ and 7.5 in turn.
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