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以高岭土为原料,采用晶种替代模板剂在水热条件下合成ZSM-5分子筛。考察了晶种质量分数、碱硅摩尔比及晶化时间对合成分子筛的影响。用XRD、FESEM、N2吸附-脱附、NH3-TPD等手段对合成样品进行了表征,并在甲醇制芳烃(Methonalto Aromatics,MTA)反应中评价其催化性能。结果表明:晶种质量分数为3%,Na OH/Si O2摩尔比为0.15,晶化时间为24 h,晶化温度为200℃时,合成出的ZSM-5分子筛相对结晶度最高为96%,晶粒为典型六棱柱状,大小约为1μm。合成的ZSM-5分子筛在MTA反应中具有较高的催化活性,BTX和芳烃选择性分别为29.7%和31.6%,较南开ZSM-5原粉分别提高1.5%和0.3%。
Using kaolin as raw material, ZSM-5 molecular sieve was synthesized under hydrothermal conditions by using seed instead of templating agent. The effects of the mass fraction of seed crystals, the molar ratio of alkali to silicon and the crystallization time on the synthesis of molecular sieves were investigated. The synthesized samples were characterized by XRD, FESEM, N2 adsorption-desorption, NH3-TPD, and their catalytic performance was evaluated in the reaction of methanol to aromatics (MTA). The results show that the relative crystallinity of ZSM-5 zeolite synthesized is up to 96% when the mass fraction of seed crystals is 3%, the molar ratio of Na OH / Si O2 is 0.15, the crystallization time is 24 h and the crystallization temperature is 200 ℃. , The grain is a typical hexagonal prism, the size of about 1μm. The synthesized ZSM-5 zeolite has high catalytic activity in MTA reaction with BTX and aromatic selectivity of 29.7% and 31.6%, respectively, which is 1.5% and 0.3% higher than that of Nankai ZSM-5.