钛硅分子筛固定床催化环己酮肟的绿色合成  

Green production of cyclohexanone oxime with a fixed-bed reactor using shaped titanosilicate catalysts

作　　者：吴静[1] 杨玉林[1] 丁姜宏[1] 黄仕杰[1] 吴鹏[1] 

机构地区：[1]华东师范大学化学系,上海市绿色化学与化工过程绿色化重点实验室,上海200062

出　　处：《科学通报》2015年第16期1538-1545,1-2,共8页Chinese Science Bulletin

基　　金：国家自然科学基金(21373089,U1162102);教育部博士点基金(2012007613000)资助

摘　　要：采用挤条成型的方法,通过添加造孔剂、黏结剂和水,制备了3种典型钛硅分子筛(Ti-MOR,Ti-MWW和TS-1)的成型催化剂,并研究了以H2O2为氧化剂,成型催化剂催化环己酮液相氨氧化反应的固定床工艺过程.首先考察了钛硅分子筛粉末在环己酮氨氧化间歇反应中的催化活性,发现3种钛硅分子筛的催化性能是Ti-MOR>TS-1>Ti-MWW.其后在固定床连续反应器上,比较了这3种成型钛硅催化剂的催化性能,结果表明,Ti-MOR比TS-1和Ti-MWW表现得更为优异,这与间歇反应结果一致.另外,系统地考察了影响成型Ti-MOR分子筛催化该反应活性和肟选择性的因素.在最优化反应条件下成型Ti-MOR催化剂表现出非常出色的催化性能,环己酮转化率和环己酮肟选择性分别高于95%和99%.成型Ti-MOR催化剂在固定床连续反应的寿命评价实验中,可以实现连续运行360 h,环己酮的转化率保持在95%,肟的选择性高于99%,H2O2残留量为3%.积炭和部分活性位Ti的流失是造成催化剂失活的主要原因,失活的Ti-MOR通过在空气中823 K焙烧可以有效再生,再生催化剂的催化性能约为新鲜催化剂的80%,但对环己酮肟的选择性仍维持在99%以上.Three representative extruded titanosilicate catalysts, Ti-MOR, TS-1 and Ti-MWW, were prepared from corresponding titanosilicate powders by adding a pore-forming agent （sesbania powder）, 30 wt.% alkaline silica sol as a binder, and water. The performance of the ground powder catalysts in the liquid-phase ammoximation of cyclohexanone in a batch reactor was first investigated, giving the order of catalytic activity of Ti-MOR 〉 TS-1 〉 Ti-MWW. The extruded catalysts were then used in a green process to produce cyclohexanone oxime in a fixed-bed reactor with hydrogen peroxide as the oxidant. When the ammoximation was performed in the fixed-bed reactor, where the products and catalyst were easily separated, Ti-MOR proved to be more efficient than conventional TS-1 and Ti-MWW, consistent with the results obtained for the batch reaction. The reaction parameters for the shaped Ti-MOR catalyst in a continuous fixed-bed reactor were then optimized systematically. Ti-MOR gave a cyclohexanone conversion of 〉95% and oxime selectivity of 〉99% under the optimized reaction conditions. The lifetime of the shaped Ti-MOR catalyst in the ammoximation of cyclohexanone in the continuous fixed-bed reactor reached 360 h while maintaining a cyclohexanone conversion of over 95%, oxime selectivity exceeding 99%, and residue of unconverted H202 of about 3%. Catalyst deactivation was elucidated to be caused by coke deposition and partial loss of Ti active sites. The deactivated Ti-MOR catalyst was regenerated effectively by removing the organic species occluded within the zeolite pores by air calcination at 823 K. The catalytic activity of the regenerated Ti-MOR was about 80% that of the fresh one, but it still provided an oxime selectivity of 〉99%.

关 键 词：钛硅分子筛 Ti-MOR 固定床 环己酮肟 液相氧化 

分 类 号：TQ23[化学工程—有机化工]