摘要
采用溶胶 凝胶法合成出具有Keggin结构的纳米复合杂多酸H3 PW12 O40 /SiO2 催化材料 ,用IR ,UV ,XRD ,TEM等手段研究了其结构形态 ;并考察了纳米催化剂对合成丙烯酸正丁酯的应用研究。结果表明 ,H3 PW12 O40 /SiO2 催化剂平均粒径为 4 0nm ,是一种非晶态复合物 ,H3 PW12 O40 和SiO2 之间存在着强烈的化学作用 ,纳米粒子对合成丙烯酸正丁酯有很好的催化活性 ,其最佳催化条件为 :酸醇摩尔比为 1∶1 2 ,催化剂用量为酸质量的 10 % ,反应温度为 90~ 96℃ ,反应时间 5h ,酯化率达到 94 37% ,酯收率为 91 2 %。这与纳米粒子具有较强的酸表面中心 ,高的比表面积以及“假液相”
A new nanometer complex heteropoly acid with Keggin structure, H3PW12O40/SiO2 were prepared by sol-gel method, and were characterized with IR, UV, XRD and TEM techniques; By means of this nanometer catalytic materials, the optimum catalytic conditions of the n-butyl acrylate, synthesis have been studied. The results show that the complex heteropoly acid H3PW12O40/SiO2 nanoparticles have the mean grain size of 40 nm and they are typical amorphous.. A strong chemical interaction exists between H3PW12O40 and silica surface. The nanoparticles have high catalytic activity for synthesizing n-butyl acrylate. The optimum catalytic conditions are as follows: the mole ratio of acrylic acid and n-butyl alcohol is 1: 1.2, the reaction temperature is approximately 90-96 degreesC, and the catalyst quantity in the reaction is 10% of the acid mass. The conversion proportion is 94.37% and product yield 91.2% in 5 h. Apparently; the unique structure of the Keggin anions and surface acid center and the high specific surface area and the pseudoliquid Phase of H3PW12O40/SiO2 play an important role in the esterification reactions with the acid catalyst.
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2004年第10期1217-1220,共4页
Spectroscopy and Spectral Analysis
基金
湖北省教育厅重点科研项目 (2 0 0 3A0 0 9)
湖北大学重点研究项目 (A0 0 2 0 )资助