【摘要】 分别以三乙胺(TEA)、二乙胺(DEA)和TEA+DEA为模板剂合成SAPO-34分子筛,考察模板剂对该分子筛的合成、物化性质及催化性能的影响。结果表明,以DEA为模板剂能够得到纯相的SAPO-34,但合成条件比较苛刻。以TEA为模板剂得不到纯相的SAPO-34,只能得到CHA/AEI的共生结构产物。以DEA+TEA为模板剂,当DEA的量大于总模板剂量的一半时,得到的是纯相SAPO-34;随着模板剂中DEA比例的增加,晶化产物中的硅含量增加,孔体积和比表面积不断减小,晶粒逐渐增大,酸中心数不断减少,酸强度有所减弱;将得到的分子筛用于MTO反应,随着模板剂中DEA比例的增加,产物中乙烯收率降低,丙烯收率提高,C2=+C3=选择性逐渐增加。更多还原

【Abstract】 Using various templates,triethylamine(TEA),diethylamine(DEA)and TEA+DEA,SAPO-34 molecular sieve was synthesized respectively.The test results showed that pure SAPO-34 crystal phase(CHA) could not be formed when using TEA as template,only CHA/AEI intergrowth crystal was formed.When using DEA as template,pure CHA phase was obtained under narrow synthesis conditions.SAPO-34 with pure CHA structure could be easily synthesized when using TEA+DEA mixed template having a DEA/TEA ratio of over 1.The effects of templates on the physicochemical properties and catalytic performance of the obtained products were studied.It was found that with the increase of DEA proportion in the mixed template,the content of silicon in the obtained molecular sieve increased,the specific surface area and pore volume decreased,the crystal size increased,the number of active acid sites decreased and with acid strength weaken.When the obtained SAPO-34 molecular sieve samples were used as catalysts in the methanol-to-olefin(MTO) reaction,it was observed that with the increase of DEA proportion in the mixed template,the ethylene yield decreased,propylene yield increased,and the selectivity of C=2+C=3 increased gradually.更多还原