Study On Hydrogenation Of Phenols

Phenolic compounds catalytic hydrogenation synthesis of cyclohexanone or cyclohexanol can be used as petrochemical and fine chemical industry is a key intermediate,is widely used in pharmaceutical and other areas.At present,China’s demand for cyclohexanol and cyclohexanone rapid growth.However,the domestic production of cyclohexanone appeared in short supply of the status quo,so a lot of the difference between the need to import from abroad.Therefore,it is necessary to design a highly efficient synthetic route.In order to synthesize high quality cyclohexanol or cyclohexanone,the effect of catalyst and its technological conditions on its catalytic effect was investigated.From which the best process conditions were obtained and the possible mechanisms were explored.The optimum process was combined with the reaction principle and simulated with Aspen Plus.According to the simulation results and the reaction principle,the principle process is designed.Specific work is as follows:1.The single factor method was used to study the catalyst,acid and alkali,temperature,time,solvent,and the optimum process was determined.The results showed that the hydrogenation catalysts were screened,namely Rany Ni and Pd/C.The addition of Rany Ni favors the synthesis of cyclohexanol,which favors the synthesis of cyclohexanones.For one step synthesis of cyclohexanone,the catalyst Pd/C is preferred;Rany Ni can be selected for two-step synthesis of cyclohexanone.At the same time,different models of Rany Ni screening.The results show that the A-45 model Rany Ni catalytic hydrogenation effect is the best.And the optimum process of synthesizing 1,4-cyclohexanediol was obtained.Under the catalysis of Rany Ni,the Lewis acid ZnCl2 was used as a promoter and co-catalyzed by hydroquinone at 130 ℃ and 1 MPa The reaction rate was 99.91%and the selectivity of 1,4-cyclohexanediol was 99.95%.2.1,4-cyclohexanedione was synthesized by oxidation of 1,4-cyclohexanediol obtained by complete hydrogenation.According to the different sources of oxygen divided into two processes,namely,air oxidation and hydrogen peroxide oxidation method.The effects of different process conditions were investigated.The results showed that A and B were used as the catalyst in the air oxidation method,the stirring speed was 800 r/min,the amount of catalyst was 5%equivalent,and the conversion was 2:3,30%H2O2 as oxidant,n(H2O2):n(1,4-cyclohexane hydrogen)=5:1,reacted at 80 ℃ for 8 h,the conversion rate was 98.94%,the selectivity was 80.21%,and the yield was over 79%.3.The optimum process was obtained from the synthesis of 1,4-cyclohexanediol from hydroquinone and the synthesis of 1,4-cyclohexanedione by re-oxidation.The simulation software Aspen Plus was used to simulate the process.The yield reactor RYield and the RadFrac distillation column,which has been rigorously calculated,have been used to achieve the separation and purification of reactants and products.The purity of 1,4-cyclohexanedione is over 90%.