Catalytic Application of Synthesizing n-Butyl Acrylate by a New Type Nanometer Complex Heteropoly Acid Catalyst H3PW12O40/SiO2
ZHOU Li-qun1，2，LIU Shi-zhong2，SUN Ju-tang1
1. Faculty of Chemistry and Molecular Science, Wuhan University, Wuhan 430072，China 2. Faculty of Chemistry and Material Science, Hubei University, Wuhan 430062，China
Abstract：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 ℃，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.
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