摘要
采用XRD、SEM、NH3-TPD等方法研究了以三乙胺(TEA)、四乙基氢氧化铵(TEAOH)及二者的混合物为模板剂合成的产物的结构及物化性能,并以甲醇为探针分子,在固定床反应器上对合成产物在甲醇制取烯烃(MTO)反应中的催化性能进行了评价。结果表明,模板剂的种类及配比对所得产物的晶相结构、晶粒大小、酸强度、酸量以及催化性能有重要影响。双模板体系中,当n(TEAOH)/n(TEA)=0.037～0.186时,得到纯相SAPO-34分子筛;且当n(TEAOH)/n(TEA)=0.093时,得到的SAPO-34分子筛晶粒较小(1.0μm左右)且均匀,酸度适中,低碳烯烃(C2=～C4=)的选择性94.98%,催化寿命415min,较单独以TEA〔n(TEA)/n(Al2O3)=2.15〕或TEAOH〔n(TEAOH)/n(Al2O3)=2.0〕为模板剂合成的催化剂的低碳选择性(88.22%和89.29%)和寿命(170min和165min)均有明显提高,且积炭速率(0.016%/min)明显降低。
The structure and property of products,which were synthesized with TEA and/or TEAOH as template（s）,have been investigated carefully with XRD,SEM and NH3-TPD techniques.The catalytic performance of products has been investigated in the conversion of the methanol-to-olefine（MTO）fixed-bed process.The results from the XRD,SEM,NH3-TPD measurements showed that the types and ratios of the templates had a great influence on the structure,crystal size and the acidity of products.In the dual-template system,the pure SAPO-34 molecular sieves could be obtained as n（TEAOH）/n（TEA）=0.037～0.186,and the SAPO-34 molecular sieve with a smaller and more uniform crystal,mild acidity could be obtained as n（TEAOH）/n（TEA）=0.093.The catalytic evaluation showed that the SAPO-34 synthesized with n（TEAOH）/n（TEA）=0.093 exhibited a higher selectivity to light olefin（C2^n～C4^n）（94.98%）,longer lifetime（415 min）than the SAPO-34 prepared with the single TEA 〔n（TEA）/n（Al2O3）=2.15,88.22%,170 min〕 or TEAOH 〔n（TEAOH）/n（Al2O3）=2.0,89.29%,165 min〕 as template,and its coke deposition rate has fallen remarkably to 0.016%/min.
出处
《精细化工》
CAS
CSCD
北大核心
2010年第7期672-677,共6页
Fine Chemicals
基金
国家高技术研究发展计划(863计划)(2007AA052326)~~
