Optimization Of The Preparation Process Of Cumene Hydroperoxide And Dimethylbenzyl Alcohol And Research On The Recycling Of By-products

Dicumyl peroxide(DCP)is a widely used industrial chemical.It can be used as initiator of monomer polymer,vulcanizing agent of polymer materials,crosslinking agent,curing agent,flame retardant additive,etc.Commonly known as"industrial MSG".Its production mainly involves a continuous process,in which the preparation of cumene hydroperoxide(CHP)and dimethyl alcohol(CA)is undoubtedly the key step in the production of DCP.On the basis of consulting domestic and foreign literature,the properties,uses and synthesis methods of CHP and dimethylbenzol CA are summarized.On the basis of the existing synthesis route,it is proposed to use heterogeneous composite metal oxide solid base La₂O₃-CuO-MgO(L-C-M)catalyst and supported Pd/Al₂O₃catalyst to replace the traditional catalyst.Applied to the reaction system of liquid phase oxidation of cumene and catalytic hydrogenation of CHP.After the continuous reaction,the neutralization treatment is not required,and the catalyst can be reused.Composite metal oxide catalyst CuO-MgO(C-M)was prepared by coprecipitation method.The preparation conditions are as follows:calcination temperature T=700??n(Cu):n(Mg)=0.03:1.Furthermore,the same method was used to prepare La₂O₃-MgO and L-C-M catalysts at a molar ratio of n(La):n(Mg)=0.8:1.Compared with the reported catalysts,L-C-M has the best catalytic activity for the oxidation of cumene.XRD,SEM,BET,CO₂-TPR and XPS were used to characterize the three kinds of catalysts in order to study the synergistic catalysis among various elements.The results show that the synergistic effect of dispersed copper/magnesium particles and La-Cu-Mg in L-C-M catalyst is the main reason for the higher activity of the catalyst.Promote the transfer of electrons between ions,induce the formation of more oxygen vacancies,and then increase the amount of chemically adsorbed oxygen on the catalyst surface and improve the oxidation performance.L-C-M was tested for cycle stability.According to the analysis of the characterization results of O1s XPS,its high oxygen mobility inhibits the coking of the catalyst,so it keeps a good crystalline structure and has good stability.Box-Behnken response surface methodology was used to optimize the oxidation conditions of cumene.Under the optimum conditions of oxygen flow rate=540m L·min^-1,reaction temperature=100?,reaction time=7.5 h^-1and catalyst dosage=1.5%.The conversion rate of cumene(X_IPB/%)and selectivity of CHP(S_CHP/%)were 93.29%and 54.40%,respectively.A continuous distillation process was designed to refine cumene oxidation products.The distillation process of CHP-CA-acetophenone-cumene mixture system was simulated by Aspen Plus simulation software,and the conditions were optimized by orthogonal test.After optimization,the purity and yield of cumene hydroperoxide reached 99.71%and 100.00%,respectively.The supported catalyst Pd/Al₂O₃,was prepared by impregnation method and characterized by XRD,FT-IR,H₂-TPR and BET.The results show that the catalyst supported on palladium has excellent structure and active center.CA was prepared by hydrogenation in a fixed bed reactor with Pd/Al₂O₃as catalyst and CHP oxidation solution as raw material.The effects of temperature and pressure on the reaction process were investigated,and the optimum reaction conditions were determined as follows:reaction temperature T=60?,reaction pressure P=1.5 MPa,volume ratio of hydrogen to CHP raw material liquid=240,liquid hourly space velocity LHSV=5 h^-1.Under the optimized conditions,the conversion rate of CHP(X_CHP/%)reached95.79%,and the selectivity(S_CA/%)and yield(Y_CA/%)of CA were 92.10%and88.2%,respectively.Because there are some by-products in the hydrogenation products,the refining process of vacuum distillation-extractive distillation-solvent recovery distillation was studied and optimized by Aspen Plus software.Under the optimized conditions,the purity and yield of CA reached 99.99%and 98.96%,respectively.This study provides technical support for the industrialization of cumene oxidation and CHP liquid phase hydrogenation.