氧化铬负载氧化硅层柱磷酸锆的合成及催化性能

采用新途径制备了氧化铬负载氧化硅层柱磷酸锆催化剂 ,首先制备了 3 -胺丙基三乙氧基硅 (APS)层柱磷酸锆 ,浸渍Cr(NO3) 3·6H2 O溶液后在 5 5 0℃下焙烧 ,将其转化为氧化铬负载氧化硅层柱磷酸锆催化剂。与常规浸渍制备方法相比 ,所获得的催化剂样品中铬元素与载体间的相互作用强 ,促进了氧化铬在载体上的分散 ,在氧化铬负载量达到 5 0 %时无晶相氧化铬生成 ,催化剂的比表面积最高达到 2 30m2 /g。在苯羟基化反应中用新途径制备的催化剂苯的转化率可以达到 2 9.6 % ,高于常规方法制备的氧化铬负载氧化硅层柱磷酸锆催化剂。随铬负载量的提高 ,反应过程中活性组分的流失量降低 ,催化剂活性具有较强的抗流失性能

Preparation and Catalytic Properties of Chromia Supported Silica Pillared Zirconium Phosphate

Chromia supported silica pillared zirconium phosphate was prepared by a novel way. In this method 3-aminopropyltriethoxysilane(APS) pillared zirconium phosphate was prepared first, after impregnation with Cr(NO 3) 3·6H 2O solution, the samples were calcinated at 550 ℃ to transform it to chromia supported silica pillared zirconium phosphate. Compared with the catalyst obtained by normal impregnation,the sample has stronger interaction between Cr and supportor which promoted the dispersion of chromia on supportor. There is not crystalline chromia when the content of chromia in samples is 50% and its specific surface area is up to 230 m 2/g. In hydroxylation of benzene, the highest conversion of benzene is 29.6%, which is much higher than those samples prepared by normal way. In the same time, Cr leaching from samples decreased with the increase of Cr loading in the reaction, which indicats that the samples has a higher stability against the Cr leaching.