无有机模板剂制备ZSM-5分子筛及其环己烯水合应用

以硫酸铝、水玻璃为主要原料,无有机模板剂条件下采用两步水热晶化法合成ZSM-5分子筛。系统研究钠硅比、水硅比和晶化时间等因素对ZSM-5分子筛结晶度和晶粒尺寸的影响。采用XRD和SEM对制备的ZSM-5分子筛进行结构表征,并考察ZSM-5分子筛在环己烯水合反应中的催化性能。结果表明,在一定钠硅物质的量比和水硅物质的量比范围,ZSM-5分子筛结晶度随钠硅物质的量比的增加与水硅物质的量比的减小而升高。无有机模板剂条件下制备ZSM-5分子筛,不仅降低生产成本,减少对环境的危害,而且在环己烯水合反应中表现出较好的催化活性,随着ZSM-5分子筛晶体尺寸减小,环己烯转化率提高。

Synthesis ZSM-5 zeolite without organic template and its application in cyclohexene hydration

ZSM-5 zeolite has been synthesized with aluminum sulfate and sodium silicate as the main raw material by two-step hydrothmal crystallization in the absence of organic templates.The influence of Na₂O/SiO₂ ratio,H₂O/SiO₂ ratio and crystallization time on the crystallinity and grain size of the zeolite have been investigated systematically.Samples with different synthesis condition have been prepared and characterized by X-ray diffraction and scanning electron microscopy in order to investigate the crystal structure of ZSM-5.The catalytic performance for hydration of cyclohexene to cyclohexanol has also been inestigated.The results showed that in a certain range of Na₂O/SiO₂ mole ratio and H₂O/SiO₂ mole ratio,the crystallinity of ZSM-5 increases with the increase of Na₂O/SiO₂ ratio and the decrease of H₂O/SiO₂ ratio.The ZSM-5 synthesized with organic-free templates not only reduce environmental hazards and production cost,but also have good catalytic performance in the hydration of cyclohexene.Cyclohexene conversion increases with the decrease of crystal particle size.