VOx/SiO2-Al2O3催化剂催化苯羟基化制苯酚

以硅溶胶为硅源、偏铝酸钠为铝源及环己胺合成SiO2-Al2O3复合氧化物，并采用水热合成法合成了VOx/SiO2-Al2O3催化剂。采用XRD、SEM、TEM、XPS、NH3-TPD、N2物理吸/脱附等手段对此催化剂和复合氧化物微观结构进行表征分析。由表征结果可知钒活性中心能够高分散于此复合氧化物表面，VOx/SiO2-Al2O3催化剂呈现层片积雪状；当钒的含量为4%时，催化剂中V4+含量最大且总酸量契合于此反应所需要的催化酸环境。探究了4%VOx/SiO2-Al2O3催化剂对苯羟基化制苯酚反应的催化性能，结果表明：基于高分散活性中心、V4+含量最大及载体酸性环境等优点而表现出良好的催化性能，苯转化率为48.1%，苯酚选择性为99.6%。

Catalytic Hydroxylation of Benzene to Phenol with VOx/SiO2-Al2O3 Catalyst

SiO2-Al2O3 composite oxide were synthesized by using silica sol as silicon source, sodium metaaluminate as aluminum source and cyclohexylamine, and VOx/SiO2-Al2O3 catalyst was synthesized by hydrothermal synthesis. The microstructure of the catalyst and composite oxide was characterized by XRD, SEM, TEM, XPS, NH3-TPD and N2 physical adsorption/desorption. From the characterization results, it was known that the vanadium active center could be highly dispersed on the surface of the composite oxide, and the VOx/SiO2-Al2O3 catalyst showed a layer of snow. When the vanadium content was 4%, the content of V4+ in the catalyst was the largest and the total acid amount of the catalyst was consistent with the catalytic acid environment needed for this reaction. The catalytic performance of 4%VOx/SiO2-Al2O3 catalyst for the hydroxylation of benzene to phenol was investigated. The results showed that the catalyst showed good catalytic performance based on the advantages of high dispersion active center, the content of V4+ in the catalyst was the largest, the acid environment of the carrier and other advantages. The conversion of benzene was 48.1% and the selectivity of phenol was 99.6%.