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采用BET ,XRD ,TG DTA ,FT IR ,XPS和NH3 TPD等分析手段 ,研究了活化焙烧温度 (5 0 0～ 80 0℃ )对B2 O3 /ZrO2 催化剂织构 /结构、表面性质和环己酮肟气相重排反应的影响 .催化剂活化焙烧温度升高促进了ZrO2 向单斜晶相转化 ,同时活性组分氧化硼由以BO4为主要结构单元的物种转变为以BO3 为基本结构单元的B2 O3 ,导致催化剂比表面积、孔体积以及表面酸量减小 ,ZrO2 与B2 O3 之间的相互作用减弱 .70 0℃活化焙烧的催化剂表面拥有最大比例的中强酸中心 ,而且Beckmann反应的活性稳定性最高 .这些结果表明 ,活化焙烧温度对B2 O3 /ZrO2 催化剂上气相重排反应的影响主要是通过改变催化剂中B原子的配位状态和表面酸性实现的 .
The effects of activation calcination temperature (500 ~ 800 ℃) on the texture and structure, surface properties and cyclohexanone of B2 O3 / ZrO2 catalysts were studied by means of BET, XRD, TG DTA, FT IR, XPS and NH3 TPD. Oxime vapor phase rearrangement reaction.The increase of catalyst activation calcination temperature promotes the conversion of ZrO2 to monoclinic phase and the conversion of the active component boron oxide from the species with BO4 as the main structural unit to the B2O3 with BO3 as the basic structural unit , Resulting in a decrease of specific surface area, pore volume and surface acidity, and a decrease of the interaction between ZrO2 and B2O3. The surface of the catalyst calcined at 70 0 ℃ has the largest proportion of moderately strong acid sites and the Beckmann reaction has the highest activity stability These results indicate that the effect of activation calcination temperature on the gas phase rearrangement reaction on B2 O3 / ZrO2 catalyst is mainly achieved by changing the coordination state and surface acidity of B atoms in the catalyst.