以聚二甲基二烯丙基氯化铵为模板合成多级孔ZSM-5分子筛

以廉价的水玻璃、硫酸铝为原料,聚二甲基二烯丙基氯化铵(PDADMAC)为介孔模板,通过水热法合成了多级孔ZSM-5分子筛,并采用X射线衍射、扫描电镜和N2吸附-脱附等手段对所得样品进行了表征。考察了PDADMAC加入顺序和用量、硅铝比、正丁胺用量、水硅比以及氯化钠用量等合成条件对多级孔ZSM-5分子筛的合成和孔结构性质的影响。结果表明:制备凝胶时将PDADMAC加入至硅源中合成的多级孔ZSM-5分子筛介孔孔容较大,介孔孔径分布相对集中;随着PDADMAC用量的增加分子筛的介孔孔容增大;适当的硅铝比和水硅比有利于合成出较大介孔孔容的多级孔分子筛;氯化钠的加入可在一定范围内调节多级孔ZSM-5分子筛的介孔孔容和介孔孔径分布。

Synthesis of hierarchical ZSM-5 zeolite using poly(diallyl dimethyl ammonium chloride) as mesoporous template

Using cheap water glass and aluminum sulfate as raw materials and poly(diallyl dimethyl ammonium chloride)(PDADMAC)as mesoporous template,hierarchical ZSM-5 zeolite was synthesized by hydrothermal method,and the samples were characterized by XRD,SEM and N2 adsorption-desorption.The effects of the adding order and dosage of PDADMAC,the ratio of silicon to aluminum,the amount of n-butylamine,the ratio of water to silicon and the amount of sodium chloride on the synthesis and pore structure of ZSM-5 zeolite were investigated.The results showed that the addition of PDADMAC to silica source led to the formation of hierarchical ZSM-5 zeolite with larger mesoporous volume and narrow pore size distribution.With the increase of PDADMAC dosage,the mesoporous volume of hierarchical ZSM-5 zeolite increased.The appropriate ratios of SiO2 to Al2O3 and H2O to SiO2 ratio were faverable for the synthesis of hierarchical ZSM-5 zeolite with larger mesoporous volume.The addition of sodium chloride adjusted the mesoporous volume and pore size distribution of mesoporous ZSM-5 zeolite in a certain range.