Liquid Phase Catalytic Oxidation Of P-cresol To P-hydroxybenzaldehyde

P-hydroxybenzaldehyde (PHB) was an important intermediate which was widely used in organic synthesis.There had been a century about its discovery and synthesis, with the development of society and scientice, it was widely used as chemical, flavor, electroplating, liquid crystals, pharmaceuticals and so on.In this paper the preparation conditions of catalyst were studied, p-cresol as the raw material was used in liquid phase catalytic oxidation synthesis of PHB discussing the various factors on the catalytic activity and charactering the product, and the catalysts were characterized by XRD,FT-IR,XPS,BET,TPR.The main research was as follows:1.The catalyst loaded on theγ-Al2O3 was prepared by impregnation with cobalt acetate and copper acetate. P-cresol as the raw material was used in liquid phase catalytic oxidation synthesis of PHB. It was found that reaction temperature 65℃, reaction time 10h and mole ratio of 1:3:16 of p-cresol:methanol:NaOH were the optimum reaction conditions under optimum conditions of catalyst preparation, the yield was 45% at this time.2.The test of IR and GC-MS were carried out for the product synthesized under the stated conditon above.The characteristic peaks indicated the product of PHB.3.Various factors on the catalytic activity were discussed. The research showed that the reaction temperature, Co/Cu molar ratio, impregnation concentration and reaction time had a certain impact on the catalytic activity, and the catalyst reuse was investigated. The catalytic activity was the best under the conditions of 65℃, Co/Cu molar ratio of 5:1, dipping to 6% concentration and 10h of reaction time.4.The Crystal structure, surface electronic state and specific surface area of Co-Cu/γ-Al2O3 were characterized by XRD,XPS,FT-IR,TPR,BET.The result showed the best calcination temperature of catalyst was 400℃, there was no strong interaction between active component and carrier, at this time surface area of catalyst was the most and the dispersion of active component was the best, the results of XRD,IRand XPS were consistent, active component of the catalyst was Co3O4, Co3+/Co2+ redox cycle promoted the recation.