Study Of 2,3,6-trimethylphenol Oxidation In A Rotating Packed Bed Reactor

Vitamin E is a fundamental vitamin for our health,which is fat-soluble to the body.It has extensive worth of industry application and spacious market prospects.At present,synthetic vitamin E is the main way to meet the needs of the world.2,3,5-trimethyl-1,4-benzoquinone(TMQ)is an important intermediate for the synthesis of vitamin E.At present,the industrial production of TMQ mainly starts from the oxidation of 2,3,6-trimethylphenol(TMP).The TMP catalytic oxidation reaction is a liquid-gas multi-phase oxidation process.With the difficulty in absorbing oxygen and low mass transfer efficiency,the reaction system has the problems of long reaction time and low production efficiency.In this paper,a rotating packed bed(RPB)was used in the process of TMP catalytic oxidation to synthesize TMQ.In order to shorten the reaction time and improve production efficiency,using higee technology to intensify the mixing process and mass transfer process of the reaction system.In TMP catalytic oxidation system,the gas phase was oxygen which was used as oxidant and the catalyst was CuCl2 and FeC13 aqueous solution.Under different process conditions,the effects of various operating conditions on the mixing of reaction and the mass transfer process were studied.The suitable operating conditions of the reaction were determined.The feasibility and advantages of the RPB reactor for the process were explored.The findings of the research are as follows:(1)In the RPB reactor,with the increase of reaction temperature,amount of catalyst,the volume fraction of aqueous phase and liquid flow rate the TMP conversion and the TMQ yield increased.With the increase of gas flow rate and rotational speed,the TMP conversion and the TMQ yield of the reaction increased at first,and decreased at the high range.The reaction temperature was 75?,the volume fraction of aqueous phase was 0.83,the rotational speed was 800 r·min-1,the liquid flow rate was 40 L·h-1,and gas flow rate was 10 L·h-1,which is the suitable operating conditions.At 80 min,the TMP conversion was 96.91%and the TMQ yield was 62.61%.Under the same conditions,the TMP conversion and the TMQ yield of oxygen catalytic oxidation process wre higher than that of air catalytic oxidation process.The corrugated structure of the wire mesh packing could promote the reaction process.The Polytetrafluoroethylene material has hydrophobic property,which was conducive to the liquid dispersion of the reaction system.Compared with other reactors,the RPB reactor effectively intensified the TMP catalytic oxidation process,which is beneficial to improve the TMP conversion and TMQ yield of the reaction.(2)In RPB+STR process,the TMP conversion and TMQ yield increased with the increase of rotational speed,volume fraction of aqueous phase and temperature of the reaction.With the increase of liquid flow rate,the TMP conversion increased all the time,and the TMQ yield increased first and decreased then.The suitable operating conditions:reaction temperature was 75?,rotational speed was 1000 r·min-1,liquid flow rate was 30 L·h-1,gas flow rate was 60 L·h-1.Comparing the effect of different reactor combinations on TMP catalytic oxidation,the TMP conversion of RPB+STR process is higher than the RPB reactor,but the TMQ yield is lower than the RPB reactor.