Study On The Isomerization Of O-dichlorobenzene

With the gradual deepening of the research on dichlorobenzene,three isomers of dichlorobenzene,especially m-dichlorobenzene and its derivatives,have been widely used as important fine chemical raw materials and intermediates in the market..They are mainly used in the synthesis of pesticides,pharmaceuticals,dyes,pigments,plastics and preservatives in fine chemical production process.The demand for o-dichlorobenzene is much lower than that for m-dichlorobenzene for now.At present,the main synthesis methods of m-dichlorobenzene are varied.Among those methods,isomerization of o-dichlorobenzene is a reasonable and feasible process route.Therefore,choosing o-dichlorobenzene as raw material to produce m-dichlorobenzene and by-product p-dichlorobenzene has great industrial value.In this study,three different types of catalysts were experimented.The degree of reaction was reflected by conversion of o-dichlorobenzene and selectivity and yield of m-dichlorobenzene.The anhydrous aluminum trichloride and hexahydrate aluminum trichloride catalyst system were determined as the best catalytic system.The suitable reaction conditions was obtained by experiment.The reaction temperature is 160,the catalyst is 15%of the raw material,the molar ratio of catalyst to water is 2:1,and the stirring speed is 300r min^-1.The highest conversion rate of o-dichlorobenzene obtained is65%.The energy of complex formed by H attacking dichlorobenzene was calculated by DFT method of Gaussian software,and the attacking position of H was obtained.Then the mechanism of isomerization of o-dichlorobenzene was analyzed.On the basis of the reaction conditions determined before,the dynamic data of a series of temperatures are measured.The reaction rate constant of each reaction at different temperatures is solved by Kd method.Then the data are regressed to get the kinetic equation of the isomerization of o-dichlorobenzene.The data experimented in two temperature points different from the kinetic experimental temperature and the value data calculated by the kinetic equation were compared to verify the obtained dynamic model.And the calculated results were in good agreement with the experimental results.It can provide data support for industrialization.The experimental results show that the correlation coefficient between the calculated values and the experimental values is 0.9829.The calculated results are in good agreement with the experimental results.The kinetic equation of isomerization of o-dichlorobenzene was established to provide the necessary data for determining the optimal operating conditions,selecting the reactor reasonably,industrialization and engineering amplification.