The Study On Intensifition Of Benzene Hydroxylation By Higee

As an important raw material for organic chemical synthesis,phenol can be used to produce bisphenol A,phenolic resin and pharmaceutical intermediates,and is widely used.The traditional cumene process route uses benzene and propylene as raw materials to undergo alkylation,oxidation and other steps,with low conversion rate and by-product large amounts of acetone.Benzene as hydrogen peroxide(H2O2)as raw material direct hydroxylation can be prepared in one step,is considered to be the most promising alternative to propylene production of phenol a route,with H2O2 as the oxidant,titanium silicon molecular sieve(TS-1)as the catalyst of the benzene hydroxylation reaction system is a liquid-liquid solid heterogeneous system,the two-phase mixing effect of the aqueous phase and the oil phase(benzene phase)is not good and the catalyst distribution is uneven will lead to the apparent reaction rate and product selectivity of the system is reduced,Strengthening the mixing of liquid-liquid-solid heterogeneous systems is the key to improving the conversion rate and selectivity of benzene hydroxylation reaction systems.As a typical process strengthening equipment,the Rotating Packed Bed(RPB)is widely used in liquid-liquid homogeneous,liquid-liquid heterogeneous and liquid-solid reaction systems,which reflects the good reaction strengthening effect.The project was to use supergravity technology for the liquid-liquid-solid heterogeneous catalytic reaction system of benzene,and the research on the direct hydroxylation process of supergravity-enhanced benzene was carried out.The kinetics of benzene direct hydroxylation process were studied with TS-1 molecular sieve as the catalyst,the reaction kinetics of benzene hydroxylation and phenol hydroxylation were obtained,and the process of benzene hydroxylation synthesis of phenol in stirred kettles(STR)and RPBs was studied,and the process conditions were optimized.The main research conclusions are follows:(1)The reaction kinetic parameters of benzene hydroxylation were obtained within the experimental condition range,the benzene hydroxylation reaction rate equation,reaction rate equation:-dc/dt=6.92×106 exp(-9760/T)CACB[TS]1.31Arrhenius equation:k=6.92×106 exp(-9760/T)[TS]1.31The activation energy of the reaction is 81.14 kJ·mol-1,and the reaction rate is proportional to the catalyst concentration to the power of 1.31.(2)The reaction kinetic parameters of phenol hydroxylation were obtained within the scope of experimental conditions,the phenol hydroxylation reaction rate equation,reaction rate equation:-dc/dt=23.88exp(-4129.17/T)CACB[TS]Arrhenius equation:k=23.88 exp(-4129.7/T)[TS]The activation energy of the reaction is 34.33 kJ·mol-1,and the reaction rate constant k is proportional to the 1st power of the catalyst concentration.Among them,the activation energy of hydroquinone was 33.75 kJ·mol-1,and the activation energy of catechol was 37.66 kJ mol-1.(3)The process conditions was studied in STR,and the better process conditions were determined.At the temperature of 60℃,the amount of catalyst is 12 g·L-1,phase ratio is 1:1.6(oil to water ratio),the hydrogen peroxide concentration is 0.32 mol·L-1 the theoretical conversion rate of benzene is 41.26%,and the selectivity of phenol is 87.15%.(4)The process conditions was studied in RPB,and the better process conditions were determined.At the temperature of 60℃,the amount of catalyst is 12 g·L-1,phase ratio is 1:1.6(oil to water ratio),the hydrogen peroxide concentration is 0.32 mol·L-1 and the RPB speed is 500 rpm,the cycle volume is 200 mL.min-1,the theoretical conversion rate of benzene is 41.26%,and the selectivity of phenol is 87.15%.