不同晶化条件对ZSM-34分子筛性质的影响

EFFECT OF CRYSTLLIZATION CONDITIONS ON PROPERTIES OF ZSM-34

以氯化胆碱为模板剂,采用模板剂法单段晶化、模板剂法两段晶化及晶种辅助的两段晶化法水热合成了不同晶粒尺寸的ZSM-34分子筛。应用X射线衍射(XRD)、扫描电子显微镜(SEM)、低温N2吸附-脱附、氨气程序升温吸附-脱附(NH3-TPD)、核磁共振(NMR)等手段对合成样品进行表征。结果表明:两段晶化法能够将晶化时间从96h缩短至72h,加入晶种后晶化时间降至24h;低温有利于ZSM-34分子筛的均匀成核;结合晶化曲线分析发现晶种辅助的两段晶化法有利于快速合成性质稳定的ZSM-34分子筛。

ZSM-34 with different sizes was synthesized successfully employing choline chloride as a template under crystallization conditions of single-stage, two-stage, two-stage with the help of seed, respectively. The products were characterized by X-ray diffraction, scanning electron microscopy, N2 adsorption/desorption, NH3-temperature programmed desorption and NMR techniques. The results show that two-stage crystallization has advantages in shorter crystallization time from 96 h to 72 h, while the two-stage crystallization with the help of seed appears much more outstanding, the crystallization process is finished after only 24 h. The crystallization curve analysis indicates that two-stage crystallization with the help of seed is helpful to rapidly synthesize ZSM-34 with stable properties.