摘要
采用草酸络合方法将WO3固载到六方介孔全硅分子筛HMS上,制得新型WO3/HMS非均相催化剂.利用SEM,TEM,N2吸附,XRD及激光拉曼光谱等手段对催化剂进行了表征,研究了催化剂在环戊烯选择性氧化合成戊二醛反应中的催化性能.结果表明,在WO3/HMS催化下环戊烯和H2O2的转化率均可达100%,戊二醛的选择性可达72%.WO3以高分散状态存在于催化剂表面.单次反应后钨的溶脱量(5.5μg/ml)很小,对反应几乎没有影响.催化剂具有较高的稳定性,可以重复套用6次.失活后的催化剂可通过简单焙烧的方式再生.
The novel heterogeneous WO3/HMS catalyst was prepared by immobilization of tungstic acid on hexagonal mesoporous silica (HMS) by a special method using oxalic acid as the complexing agent, and was characterized by means of SEM, TEM, N-2 adsorption, XRD and laser Raman spectroscopy. The influences of Si/W molar ratio on the catalytic performance of WO3/HMS, WO3/SiO2 and WO3/MCM-41 for the selective oxidation of cyclopentene to glutaraldehyde under mild conditions were investigated. The as-prepared WO3/ HMS catalyst with a Si/W molar ratio of 30 showed excellent catalytic activity and selectivity. The conversions of both cyclopentene and H,02 were near 100 % and the selectivity for glutaraldehyde reached 72 %, which are much higher than those over the WO3/SiO2 catalyst and even exceed those over the homogeneous tungstic acid catalyst. The WO3/HMS catalyst remained similar morphology and hexagonal mesoporous structure as pure HMS. The highly dispersed WO3 on the HMS surface was identified as the active phase of the catalyst. The leaching of the active species was very low and had little effect on the catalytic performance. In addition, the WO3/HMS catalyst was very stable and could be reused for at least six times. The deactivated catalyst could be regenerated by simple calcination.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2005年第4期311-316,共6页
基金
国家重点基础研究发展规划(2003CB615807)
上海市科委基础研究重点项目(02DJ14021)
上海市教委曙光计划(02SG04)资助项目.
关键词
氧化钨
六方介孔全硅分子筛
负载型催化剂
环戊烯
选择性氧化
过氧化氢
戊二醛
tungstic oxide
hexagonal mesoporous silica
supported catalyst
cyclopentene
selective oxidation
hydrogen peroxide
glutaratdehyde
