液相晶化法合成SAPO-34分子筛

分别以吗啉(Mor)和吗啉-四乙基氢氧化铵(Mor-TEAOH)为模板剂,采用液相晶化法合成SAPO-34分子筛,考察晶化温度、晶化时间和模板剂对合成SAPO-34分子筛的影响和SAP-34分子筛催化甲醇制低碳烯烃(MTO)的性能.结果表明,合成SAPO-34的适宜晶化温度和时间分别为140～180℃和96～120 h,采用吗啉-四乙基氢氧化铵(Mor-TEAOH)为模板剂合成的分子筛晶粒较小.MTO反应的较佳条件为甲醇与水的体积比为2,质量空速5 h-1,催化剂8 g,常压,380℃.该条件下,甲醇转化率达98%以上,C2H4与C3H6总的选择性达84.01%.

Synthesis of SAPO-34 Molecular Sieve by Liquid-Phase Crystallization

SAPO-34 molecular sieve was synthesized by liquid-phase crystallization using morpholine (Mor) and morpholine-tetraethylammonium hydroxide (Mor-TEAOH) as templates. The effects of crystallization temperature, crystallization time and templates on SAPO-34 molecular sieve and the catalytic performance of SAPO-34 molecular sieve for conversion from methanol to olefins (MTO)were investigated. The results showed that the appropriate synthesis conditions were crystallization temperature and time of SAPO-34 were 140-180 ℃ and 96-120 h, respectively. The smaller crystal sizes were obtained using Mor-TEAOH as template. The conversion of methanol and the selectivity of both ethylene and propylene reached more than 98% and 84.01%, respectively, over the SAPO-34 molecular sieve synthesized using Mor as template under conditions of 2 of volume ratio of methanol to water, 5 h-1 of mass space velocity, 8 g of catalyst, normal pressure and 380-400 ℃.