摘要
用共沉淀法制备了Fe和Mo的复合氧化物。运用XRD、IR、TPD和LSSR技术研究了其晶体结构、表面构造、化学吸附特性和激光促进异丁烷选择氧化反应性能。结果表明 :Fe -Mo-O的主体物相为Fe2 (MoO4 ) 3,并有少量的MoO3相 ;其表面上存在Lewis碱位 (Mo =O和Mo -O-Fe键中的O)及Lewis酸位Fe3+;异丁烷的两个甲基H分别吸附在两个相邻的Lewis碱位 (Mo =O)上形成双位分子吸附态 ;在常压和 2 0 0℃条件下 ,用一定频率的激光激发Mo =O键 10 0 0次 ,异丁烷的转化率为 5 .8% ,其反应产物是异丁烯、甲基丙烯醛和甲基丙烯酸 ,其中甲基丙烯酸的选择性为 80 %。根据实验结果 。
A complex oxide Fe-Mo-O was prepared by the coprecipitation mathod. The surface composition and structure, the chemsorption properties and the behaviors of Laser stimulated isobutane selective oxidation have been investigated by the techniques of XRD, IR, TPD and micro-reactor. There are both Lewis basic sites, O 2- in the surface Mo=O or Mo-O-Fe bonds, and Lewis acid site Fe 3+ appeared on the surface of complex oxide. Two methyl hydrogens in isobutane molecule can be chemisorbed on the terminal oxygen of neighboring Mo=O bonds on the surface of complex oxide. Under the conditions of 0.1MPa and 200℃ with the 995cm -1 Laser photons exited the Mo=O bonds 1000 times, the conversion of isobutane is about 5.8%, the reaction products are isobutene, MAL and MAA with the selectivity of MAA over 80%. Based on the experiment results, a mechanism of LSSR has been proposed for the isobutane selective oxidation to MAA.
基金
国家自然科学基金 (2 97730 31)&&
