磷铝固体酸催化水杨酸甲酯制备水杨腈的研究

Preparation of salicylic nitrile from methyl salicylate over aluminum phosphate solid acid

以拟薄水铝石和正磷酸为原料制备Al PO4固体酸催化剂,利用XRD、N2-吸附脱附和NH3-TPD等分析方法对材料的物化性质进行表征,并研究了以水杨酸甲酯与氨气为原料制备水杨腈的催化反应工艺。考察了催化剂焙烧温度、反应温度、水杨酸甲酯空速和原料配比对反应的影响。结果表明,以500℃焙烧的Al PO4固体酸为催化剂,在反应温度为480℃、水杨酸甲酯空速为0.3 h-1、氨气与水杨酸甲酯的摩尔比为14∶1时,水杨腈收率达到86.1%。焙烧温度可显著影响Al PO4催化剂表面的酸强度分布,500℃条件下焙烧的催化剂表面存在较多的强酸性位,同时具有较高的催化活性。

Aluminum phosphate(Al PO4),a kind of solid acid catalyst,is prepared from pseudo boehmite and orthophosphate,and characterized by XRD,N2-physical adsorption and NH3-TPD.The prepared catalyst is used in the preparation of salicylic nitrile from methyl salicylate and ammonia.The effects of calcination temperature,reaction temperature,space velocity of methyl salicylate and the ratio of raw materials on the process are investigated.Results show that the yield of salicylic nitrile can reach 86.1%when the Al PO4 calcined at 500℃is used as the catalyst,reaction temperature is at 480℃,the space velocity of methyl salicylate is 0.3 h-1,the ratio of ammonia to methyl salicylate is14∶1.Calcination temperature has a significant effect on the surface acidity of the catalyst.The sample treated under500℃owns more strong acidic sites on its surface,which shall be conducive to the catalytic activity.