两种拟薄水铝石对SAPO-41分子筛合成的影响

THE EFFECTS OF TWO PSEUDO-BOEHMITES ON THE SYNTHESIS OF MOLECULAR SIEVE SAPO-41

在水热体系中,以二正丙胺（DPA）为模板剂,以硅溶胶为硅源,考察了两种拟薄水铝石铝源对一维中孔磷铝分子筛SAPO-41合成的影响,并采用XRD和SEM对其进行了表征。结果表明,当n（SiO2）/n（Al2O3）在0.08-0.12范围,n（DPA）/n（Al2O3）在2.8-4范围,pH在7.5-8.5范围时,能够得到纯相SAPO-41。当采用高纯度、低孔容的拟薄水铝石时,晶化后直接生成高结晶度SAPO-41;而采用相对较低纯度、高孔容的拟薄水铝石时,晶化时首先同时生成SAPO-11和SAPO-41相,然后SAPO-11转晶为SAPO-41,结晶度相对较低。

A unidimensional medium-pore molecular sieve SAPO-41 was hydrothermally synthesized by using pseudo-boehmite as Al source, silica sol as Si source and di-n-propylamine （DPA） as template. The samples obtained were characterized by XRD and SEM. The pure phase SAPO-41 was obtained from the gels with n（SiO2）/n（Al2O3） in range of 0. 08-0.12, n（DPA）/ n（Al2O3） in range of 2.8-4, pH in range of 7.5-8.5. The effects of two pseudo-boehmites on SAPO-41 crystallization were discussed. When the pseudo-boehmite with high purity and low pore volume was used, the product was crystallized directly to SAPO-41 with high crystallization, while the pseudo-boehmite with relative low purity and high pore volume was used, the product was crystallized to SAPO-11 and SAPO-41 simultaneously, then the SAPO-11 transformed to SAPO-41 during further crystallization time, resulting in the SAPO-41 with low crystallinity.