摘要
对用溶胶-凝胶法制备的HSiW-SiO_2催化剂,首先由红外光谱和紫外漫反射光谱发现钨硅酸Keggin结构中4种特征的氧键依然存在,从而证明制备的HSiW=SiO2催化剂中,钨硅酸活性中心依然保持Keggin结构。在此基础上时用溶胶-凝胶法制备的HSiW-SiO_2和用浸渍法制备的HSiW/SiO_2进行了水相中钨硅酸流失率考察,结果表明,HSiW-SiO_2催化剂的流失率基本保持在0.94%～1.07%,而HSiW/SiO_2催化剂的流失率为3.27%,两者相差3倍多,从而证明用溶胶-凝胶法制备的负载型钨硅酸催化剂能够更好地防止钨硅酸活性中心在水相反应中的流失。
First the FT-IR and UV diffusion reflection techniques reveal that the HSiW-SiO2 catalysts still have the four kinds of special oxygen bond of the Keggin structure, so it is well proved that the HSiW-SiO2 catalysts prepared by the sol-gel method still keep the Keggin structure of HSiW and have the special acid catalytic function. Then the leakage rates between HSiW-SiO2 catalysts and HSiW/SiO2 catalysts are compared each other. The results show that the leakage rates of HSiW-SiO2 catalysts prepared by the sol-gel method with 11.1%-40. 0% mass loadings are among 0. 94%-1.07%, and the leakage rates of HSiW/SiO2 catalyst prepared by impregnation with 25% mass loading is 3.27%. That is to say, the silica-included HSiW catalyst prepared by the sol-gel method can effectively prevent the active center HSiW from leaking out in the aqueous-phase reaction.
出处
《材料导报》
EI
CAS
CSCD
北大核心
2008年第6期140-142,共3页
Materials Reports
基金
广东省自然科学基金(05300127
06021469)
广东省科技计划项目(2005B10201053)资助
