相转移法合成纳米SAPO-34及其催化二甲醚制烯烃性能  

Synthesis of SAPO-34 Nanocrystals by a Phase Transfer Method and Its Catalytic Performance in Dimethylether-to-Olefin Conversion

作　　者：王佳 张云峰 樊卫斌[2] 朱卡克[1] WANG Jia;ZHANG Yunfeng;FAN Weibin;ZHU Kake(State Key Laboratory of Chemical Engineering,East China University of Science and Technology,Shanghai 200237,China;State Key Laboratory of Coal Conversion,Institute of Coal Chemistry,Chinese Academy of Sciences,Taiyuan 030001,China)

机构地区：[1]华东理工大学,化学工程联合国家重点实验室,上海200237 [2]中科院山西煤化所,山西太原030001

出　　处：《化学反应工程与工艺》2020年第5期413-420,480,共9页Chemical Reaction Engineering and Technology

基　　金：煤转化国家重点实验室开放课题(J19-20-603)。

摘　　要：优化纳米SAPO-34分子筛的合成方法,对于提高其在甲醇或二甲醚制烯烃(MTO或DTO)反应中的催化剂寿命和双烯收率具有重要意义。为降低相转移合成纳米SAPO-34中四乙基氢氧化铵(TEAOH)的用量,本工作以TEAOH和吗啡啉(MOR)共同作为结构导向剂。在共模板体系中,通过甲苯-水相转移策略制备了纳米多级孔SAPO-34分子筛,并与常规水热法合成的分子筛进行了结构和催化二甲醚制烯烃性能的比较。采用X射线多晶衍射(XRD)、场发射扫描电镜(SEM)、氮气物理吸脱附和氨气程序升温脱附(NH3-TPD)等技术对催化剂的结构和酸性进行了表征,发现这一合成方法可以制得平均粒径约为50 nm的均匀立方晶体,实现小于100 nm晶体的可控廉价制备。该分子筛用于催化二甲醚制烯烃反应中,催化剂寿命提高近1倍,同时乙烯/丙烯的选择性提高约4%。In co-templating system using both tetraethyl ammonium hydroxide(TEAOH)and morpholine(MOR),nanocrystalline SAPO-34 was generated by a phase transfer strategy in toluene/water mixture in order to reduce the use of tetraethyl ammonium hydroxide and cost.The structure and acidity of the obtained material was characterized by X-ray diffraction(XRD),scanning electron microscope(SEM),N2 adsorption-desorption and ammonia temperature-programmed desorption(NH3-TPD).The result was compared with that of a conventional sample derived from hydrothermal synthesis using the same recipe.SAPO-34 derived from phase transfer synthesis had a uniform cubic shape with an average particle size of about 50 nm,whilst the conventional sample appeared to had diverse particle sizes.The catalytic performance of the two SAPO-34 catalysts were evaluated in dimethylether-to-olefin conversion(DOT),showing that catalyst lifetime of SAPO-34 derived from phase-transfer synthesis was almost doubled with respect to the conventional counterpart and the selectivity of light olefins(ethylene and propylene)had been increased by about 4%.

关 键 词：相转移合成 共模板法 SAPO-34 分子筛 二甲醚制烯烃 催化剂寿命 烯烃选择性 

分 类 号：O643.32[理学—物理化学]