Exploratory Study On P-cresol Catalytic Oxidation Synthetic Of P-hydroxybenzaldehyde By RPB

In this paper,the main character,application and synthesis methods of p-hydroxybenzaldehyde were summarized,also analyzed and compared each methods,think that p-cresol catalytic oxidation process with simple operation,high-yield,high-purity,raw materials easy to get,the less waste,the method will become the future p-hydroxybenzaldehyde production trends.But the technology also exists a low conversion rate of p-cresol,the product separation difficulties,a long oxidation time(generally more than eight hours) and so on.The kinetics of p-cresol oxidation synthesis of p-hydroxybenzaldehyde were studied,the reaction is a typical gas-liquid reactions,reaction rate of p-cresol with oxygen decided by transmission rate of oxygen from gas to gas-liquid interface and through the interface to the main interface determines.In view of the above question,in this paper,rotating packed bed as reactor for the synthesis reaction,the use of the features of high-gravity in strengthen gas-liquid mass transfer,in order to strengthen its reaction process and shorten the reaction time.Firstly,in alkaline environment,the methyl alcohol as the solvent,the cobaltous acetate and the cupric acetate as the catalysts,pure oxygen oxidation p-cresol synthesis p-hydroxybenzaldehyde,in the experiment,reaction time,reaction temperature,various materials were inspected to the result of the reaction.Finally,obtained the best material proportion of p-cresol to sodium hydroxide to methyl alcohol is 1:3:16(molar ratio).The best response condition as follows,reaction temperature was 70℃,reaction time was 8 hours.Secondly,rotating packed bed as reactor for the synthesis reaction,experiments on high gravity factor,liquid flow rate,gas-liquid ratio,reaction time,reaction temperature.The result indicates that the best operation parameter as follows,high gravity factor is 80,liquid flow rate is 80 L/h,gas-liquid ratio is 6(m~3/m~3),reaction temperature is 70℃.This paper is in the exploratory research stage,after useing the rotating packed bed for the reaction,the experiment did not achieve the desired effect,analyzed its possible causes, laid the foundation for improveing the process for future.