Research On The Synthesis Process Of Epoxyethylbenzene By Styrene And Hydrogen Peroxide

Epoxyethylbenzene is a very important industrial chemical and is widely used in industry. In recent years, with the strong market demand of epoxyethylbenzene and the environmental protection pressure facing on the traditional production technology, the development of reasonably economic and environmentally friendly process for epoxyethylbenzene has become an important subject in chemical industry. This paper researched and proposed a green process using H2O2 as oxidant to oxidize styrene to epoxyethylbenzene, the main research contents and results are as follows:For the synthesis of epoxyethylbenzene by styrene and H2O2, firstly we choosed the catalyst and found MgO showed better catalytic performance. And then we prepared it by many different methods and got MgO-700 which had the best catalytic property. Finally we used MgO-700 as the catalyst, inspected various influencing factors on catalytic reation by experiments and obtained the optimized reaction conditions:acetonitrile as solvent. NaOH as additive, styrene 0.47 ml (4.0mmol), n(H2O2):n(styrene)=6∶1,V(acetonitrile):V(styrene)=10∶1, MgO-700 50 mg. NaOH 10 mg,60℃and 10 h, the conversion of styrene and the selectivity to epoxyethylbenzene were 95.0% and 92.0%, respectively.We analysed the apparent thermodynamics of styrene/H2O2 epoxidation reaction system, and estimated some relevant thermodynamic data:ΔfHl,TθandΔSl,Tθof epoxyethylbenzene andΔrHl,Tθ。ΔrHl,Tθand KP,Tθof synthetic reactions at 293.15K-363.15K. temperature range. We concluded that in parallel reaction, the main reaction is endothermic reaction and the side reation is exothermic reaction, which are both spontaneous. Raising temperature can promote the production of epoxyethylbenzene and inhibit the production of benzaldehyde.At last, we studied the epoxidation reaction kinetics of styrene and H2O2 using the MgO-700 as catalyst with isothermal method and obtained some dynamic parameters:the reaction level was one, the apparent activation energy was 16.05kJ/mol, and the apparent reaction rate equation was rA=3.246e-16.05×10-3/RTCA Then we got the apparent activation energy of main reaction and side reaction of parallel reation and found that warming can promote objective-product epoxyethylbenzene generation and restrain by-product benzaldehyde generation, which is consistent with the obtained conclusion from thermodynamic analysis.