摘要
水热法合成了V -AlPO4 -5分子筛 ,用XRD和FT- IR对样品进行了表征 .以纯AlPO4 -5分子筛为基准 ,用样品单位晶胞体积的膨胀程度和红外谱图中骨架振动峰向低波数方向位移程度的大小为指标 ,定性地探索了钒源、加料方式、钒加入量和晶化时间等合成因素对于V -AlPO4- 5分子筛中骨架钒含量的影响 .结果表明以V2 O5为钒源、采用 (V +P +H2 O) +Al+R的加料方式 ,V/(Al+P) =1/80 ,2 0 0℃下水热晶化 4 8h后得到的V- AlPO4- 5分子筛中骨架钒含量最高 .H2 O2 氧化苯制苯酚的活性实验结果表明 ,苯酚收率和H2 O2 分解率同V -AlPO4-骨架钒含量具有明显的正相关性 .溶剂效应表明反应机理是羟基自由基机理 .
Vanadium substituted aluminophosphates with AFI structure (V-AlPO_4-5) were prepared by hydrothermal synthesis and characterized by XRD and FTIR. Compared with pure AlPO_4-5 sieves, the (unit) cell volume of V-AlPO_4-5 expended and the skeleton vibration peaks in FTIR spectra of V-AlPO_4-5 shifted to relative low wavenumbers, which indicated that V had incorporated into the AlPO_4-5 frameworks. By researching the expansion and shift extent, the contents of frameworks-site V atoms in the V-AlPO_4-5 and the effect of preparation condition on it such as the V source, the adding sequence, the input ratio of V source and crystallization time were qualitatively researched. When V_2O_5 as the V source, (V+P+H_2O)+Al +R, V/(Al+P)=1/80, crystallization time 48 h at 200 ℃, the V-AlPO_4-5 sample with the highest content of frameworks-site V atoms was obtained. The catalytic activity of V-AlPO_4-5 for the hydroxylation of benzene by H_2O_2 into phenol showed that the phenol yield and the decomposition of H_2O_2 increased with the content of frameworks-site V atoms, which indicated that the frameworks V species were the active sites. The solvents effect suggested that the reaction undergone through the hydroxyl-radicals mechanism.
出处
《分子催化》
EI
CAS
CSCD
北大核心
2005年第1期12-16,共5页
Journal of Molecular Catalysis(China)
基金
国家重点基础科学研究计划基金资助项目 (项目编号 :G2 0 0 0 0 480 0 5)
