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在高浓度体系下,以粗孔硅胶和偏铝酸钠为原料,TPABr为模板剂,水热晶化法制备了ZSM-5分子筛,单釜产率23%.用不同浓度的氢氧化钠溶液对ZSM-5分子筛进行改性,采用XRD、FT-IR、SEM、NH_3-TPD、XRF、N_2物理吸附等方法对改性前后的样品进行了表征,并考察了改性后ZSM-5分子筛甲醇催化转化制丙烯(MTP)反应性能.结果表明,氢氧化钠改性未破坏分子筛的骨架结构,改性后样品的酸量、介孔孔容和BET比表面积均有增加,从而改善了催化剂的抗积碳性能和反应性能.在MTP反应中,增产丙烯的效果不明显,但表现出了更好的催化稳定性(催化剂使用寿命从85 h提升至110 h),并且有利于提高副产物汽油组分(∑C5+)的产量.
Under the high concentration system, the ZSM-5 molecular sieve was prepared by hydrothermal crystallization with the crude silica gel and sodium metasilicate as raw materials and TPABr as templating agent, and the yield of single-pot was 23% .Using different concentrations of sodium hydroxide solution The modified ZSM-5 molecular sieve was characterized by XRD, FT-IR, SEM, NH_3-TPD, XRF, N_2 physical adsorption and other methods before and after the modified samples were characterized and investigated the modified ZSM-5 molecular sieve methanol (MTP). The results showed that sodium hydroxide modification did not destroy the framework structure of the molecular sieve, and the acidity, mesopore volume and BET specific surface area of the modified samples increased, which improved the catalytic performance of the catalyst Anti-carbon deposition and reactivity.In the MTP reaction, propylene production is not obvious, but it shows better catalytic stability (the service life of the catalyst is raised from 85 h to 110 h), and is beneficial to increase byproduct gasoline Component (ΣC5 +) production.