不同钛含量TAPO-5分子筛的制备及催化环己酮氨肟化  

Preparation of TAPO-5 molecular sieves with different Ti contents and their catalytic performance for cyclohexanone ammoximation

作　　者：冯国强[1] 高鹏飞[1] 王永福[1] 李海涛[1] 高春光[1] 赵永祥[1] 

机构地区：[1]山西大学化学化工学院精细化学品教育部工程研究中心,山西太原030006

出　　处：《工业催化》2017年第3期25-30,共6页Industrial Catalysis

基　　金：国家自然科学基金青年项目(21403135)

摘　　要：以氢氧化铝、正磷酸和钛酸四异丙酯为原料,N-甲基二环己基胺为模板剂,采用水热晶化法合成一系列具有不同Ti含量的TAPO-5分子筛,通过XRD、N_2物理吸附-脱附、DR UV-Vis和XRF分别对分子筛结构、织构性质、Ti的存在状态以及Ti含量等进行表征。结果表明,TAPO-5分子筛为微孔-介孔材料,其中,Ti以骨架、非骨架和锐钛矿相3种形式存在;随着Ti含量增加,3种形式的Ti含量均增加,伴随着TAPO-5分子筛的结晶度、比表面积和孔容降低。环己酮氨肟化结果表明,随着Ti含量增加,环己酮转化率和环己酮肟选择性逐渐提高,当Ti质量分数为14.8%时,环己酮转化率和环己酮肟选择性分别为92.5%和95.4%,优于目前过渡金属掺杂磷酸铝分子筛催化环己酮氨肟化的最佳结果。Using aluminium hydroxide as A1 source, phosphoric acid as P source, tetraisopropyl titanium as Ti source and N-methyldicyclohexylamine as the template, a series of TAPO-5 molecular sieves with dif- ferent titanium contents were synthesized by the hydrothermal crystallization method. The structural and texture properties, titanium coordination status and titanium contents of TAPO-5 molecular sieves were characterized by X-ray diffraction, N2-physical adsorption-desorption, diffuse reflectance UV-Vis spectros- copy and X-ray fluorescence techniques. The results showed that TAPO-5 molecular sieves were micro- porous-mesoporous materials, and there existed 3 forms of titanium ： framework titanium, extra framework titanium and anatase;the amounts of framework titanium, extra framework titanium and anatase increased with the increase of Ti loadings, while the crystallinity, BET surface area and pore volume of TAPO-5 molecular sieves decreased. The results of catalytic cyclohexanone ammoximation demonstrated that the selectivity to cyclohexanone oxime and cyclohexanone conversion increased with the increase of Ti con- tents. The selectivity to cyclohexanone oxime and cyclohexanone conversion on TAPO-5 molecular sievewith Ti mass fraction of 14.8% were 95.4% and 92.5% ,respectively,which were better than those on transition metal doped aluminophosphate molecular sieve for catalytic cyclohexanone ammoximation.

关 键 词：催化化学 TAPO-5分子筛 钛含量 环己酮氨肟化 

分 类 号：O643.36[理学—物理化学] TQ234.21[理学—化学]