介孔分子筛MCM-41的合成及其催化噻吩与异丁烯烷基化反应性能

采用水热合成法制得不同硅铝比的介孔分子筛MCM - 41 ,并通过XRD ,BET ,NH3 -TPD方法对催化剂进行了表征 ,结果表明 ,弱酸性介孔分子筛HMCM - 41具有较高的相对结晶度、较大的比表面积、孔径和酸量。同时 ,不同焙烧方式对催化剂相对结晶度及比表面积影响较大 ,N2 气氛焙烧有利于保护介孔分子筛MCM - 41的骨架完整 ,提高其相对结晶度。以噻吩为模型化合物 ,异丁烯为烷基化剂 ,对HMCM - 41分子筛催化噻吩与异丁烯的烷基化反应性能进行了考察。在反应温度 80℃、常压、进料气体 (异丁烯 /N2 摩尔比为 1 /1 )流量 5ml/min、WHSV =2 33h- 1的条件下 ,噻吩转化率高达 95%以上

Preparation and Alkylation Performance of HMCM-41 Mesoporous Molecular Sieve

Mesoporous molecular sieves MCM-41 with different Si/Al ratios were s ynthesized via hydrothermal route and characterized by X ray diffraction,NH 3 -te mperature programmed desorption and nitrogen physisorption techniques.X ray di f fraction patterns indicated that mesoporous MCM-41 had high relative crystalliz ation degree.Temperature-programmed desorption of ammonia showed acidic streng t h of MCM-41 was low but acidity of HMCM-41 was relatively high.Nitrogen adsor pt ion-desorption isotherms suggested that mesoporous MCM-41 had high BET surface area and large pore size.Two different ways of calcination had strong effects o n BET surface area and relative crystallization degree of MCM-41.Calcination un d er partial protection of nitrogen was more useful to protecting structural integ rity of MCM-41 and improving relative crystallization degree of MCM-41 than ca lcination solely under air.Using thiophene as model compounds of FCC gasoline a n d isobutene as alkylating agent,alkylation performance of mesoporous HMCM-41 w a s explored by alkylation of thiophene with isobutene.Results showed that thiop h ene conversion was higher than 95% under the conditions:80 ℃,atmospheric pre s sure,mole ratio of isobutene/nitrogen 1/1,flow rate 5 ml/min,and WHSV 2.3 3 h -1 .