MOR/BEA核壳分子筛的合成与催化性能  

Synthesis and Catalytic Performances of MOR/BEA Core-Shell Composite-Zeolites

作　　者：戴晓群[1,2] 祁晓岚[2] 郭杨龙[1] 孔德金[2] 

机构地区：[1]结构可控先进功能材料及其制备教育部重点实验室,华东理工大学工业催化研究所,上海200237 [2]中国石油化工股份有限公司上海石油化工研究院,上海201208

出　　处：《化学反应工程与工艺》2011年第5期385-392,405,共9页Chemical Reaction Engineering and Technology

基　　金：国家重点基础研究发展“973”计划(2009CB623501)

摘　　要：以丝光沸石为核相材料,用聚二烯丙基二甲基氯化铵(PDDA)对其表面进行预处理后,粘附纳米β沸石晶种并焙烧,然后加入到纳米β沸石晶化体系中进行二次晶化。晶化产物的物相、形貌和孔结构通过X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)和N2吸附/脱附技术进行表征。结果表明,得到了以丝光沸石为核相、纳米β沸石为壳层的MOR/BEA核壳分子筛,壳层的覆盖度达到96%。通过氨程序升温脱附(NH3-TPD)分别测定了纳米β沸石、丝光沸石和MOR/BEA核壳分子筛三种氢型分子筛的酸性质,结果表明MOR/BEA核壳分子筛的总酸量比丝光沸石的低,但其强酸量明显高于丝光沸石,弱酸量低于丝光沸石。并以1,3,5-三甲苯转化反应为探针反应考察了三种分子筛及其机械混合物的催化性能,在反应温度385℃,反应压力3 MPa,氢烃比3.0,进料空速3.0 h-1条件下,MOR/BEA核壳分子筛的转化率、BTX(苯+甲苯+二甲苯)选择性和歧化反应的选择性都明显高于丝光沸石、纳米β沸石两种纯分子筛及其机械混合物。MOR/BEA core-shell composite-zeolite was hydrothermally synthesized by a two-step procedure.Firstly,the mordenite cores were pre-adsorbed with nano-β seeds after pretreated with positive poly-dimethyldiallylammonium chloride（PDDA）,and then calcined in air.Afterwards,β shell grew on the modi？ed mordenite crystals in the nano-β zeolite crystallization system.The products were characterized by X-ray diffraction（XRD）,N2 adsorption-desorption,scanning electron microscopy（SEM） and transmission electron microscopy（TEM）.The results demonstrated that the MOR/BEA composite-zeolite including a mordenite core and nano-β shell was synthesized,and the coverage of β shells almost reached 96%.Mordenite,Nano-β and MOR/BEA core-shell zeolites were tested by NH3-temperature-programmed desorption（NH3-TPD） respectively.It was found that the total acid amount of MOR/BEA zeolites was lower than that of mordenite.But MOR/BEA zeolites had more stronger acid amount,and lower weak acid amount than mordenite.Moreover,the catalytic performances of the three zeolites and beta/mordenite mechanical mixture were tested by 1,3,5-TMB transformation probe reaction in which the reaction temperature was 385 ℃,the reaction pressure was 3.0 MPa,molar ratio of the hydrogen to hydrocarbons was 3.0 and the feed space velocity was 3.0 h-1.Compared to mordenite,nano-β zeolite and their mechanical mixture,MOR/BEA zeolites displayed obviously higher conversion rate,BTX（benzene ＋ toluene ＋ xylene） selectivity and disproportionation selectivity.

关 键 词：丝光沸石 Β沸石 核壳分子筛 1 3 5-均三甲苯 

分 类 号：O643.36[理学—物理化学] O643.12[理学—化学]