摘要
以十二烷基二甲基苄基溴化铵为介孔模板剂合成了具有梯级孔结构的丝光沸石分子筛,并以之为载体通过浸渍负载制备了钒基催化剂。通过X射线衍射(XRD)、N2吸附-脱附、扫描电镜(SEM)、程序升温脱附法(NH3-TPD)等技术对制备的催化剂进行了表征。由表征结果可知,制备的钒基催化剂上出现了孔径为2~3nm的介孔,比表面积及总孔容等都有不同程度增加,弱酸中心数量升高,中强酸及强酸数量下降,催化剂的相对结晶度随模板剂用量的增多也逐渐下降。催化剂上异丁烷脱氢反应评价结果表明,梯级孔结构的引入能够明显改善催化剂的异丁烷脱氢性能,催化剂上异丁烷转化率略微降低、异丁烯选择性明显升高、裂解等副反应受到抑制、积炭的聚合度有所下降。合成时模板剂的添加量存在最优值,V-MOR-2样品表现出最优的催化活性。
Hierarchical mordenites were synthesized by using dodecyl dimethyl benzyl ammonium bromide as templates and used as support for the vanadium based catalysts for iso-butane dehydrogenation reaction.The structural and acid properties were investigated by XRD,N2 adsorption,SEM and NH3-TPD.According to the characterization results,the specific surface areas and total pore volumes of the vanadium based increased due to the introduction of mesopores which were in the range of 2—3nm.Besides,the weak acid sites increased on the hierarchical mordenites supported vanadium based catalysts while the medium-strong and strong acid sites decreased as well as the crystallinity.The catalytic tests results of iso-butane dehydrogenation showed that the iso-butene selectivity largely increased due to the improved mass transfer efficiency and decreased strong acid sites although the isobutane conversion slightly decreased.The side reactions were also prohibited and the condensation degree of the coke formed during the dehydrogenation process decreased.The optimized addition catalytic performance was obtained over the V-MOR-2 sample.
作者
李芹
LI Qin(College of New Energy and Materials,China University of Petroleum(Beijing),Beijing 102249,China;China University of Petroleum-Beijing Institute of New Energy Co.,Ltd.,Beijing 102249,China)
出处
《化工进展》
EI
CAS
CSCD
北大核心
2019年第11期4965-4970,共6页
Chemical Industry and Engineering Progress
关键词
分子筛
梯级孔
催化剂
烷烃
脱氢
zeolite
hierarchical
catalyst
alkane
dehydrogenation
