Study On The Reaction Of Mixed Diisopropylbenzene Isomerization Over Modified β Zeolites

Meta-diisopropylbenzene is an important raw material, which can mainly be oxidized to resorcinol. In recent years, with the growth applied of resorcinol in many industries, the need of meta-diisopropylbenzene is also increasing. Currently, In the phenol-acetone production process, benzene-propylene alkyltion reaction unit will generate a certain amount of diisopropylbenzene as by-product. These diisopropylbenzene enter anti-alkylation unit with benzene occur alkyl transfer reaction. The Meta-diisopropylbenzene value is much higher than the value of cumene in the market, therefore, these diisopropylbenzene used for anti-cumene alkylaction actually caused the loss of more valuable meta-diisopropylbenzene. However, three isomers of diisopropylbenzene have very equivalent boiling points, meta-diisopropylbenzene (m-DIPB) and o-diisopropylbenzene are not easily sepatated, para-diisopropylbenzene is easy to sepatated relatively. Therefore, environmental friendly diisopropylbenzene isomerization on zeolite catalyst can make o-diisopropylbenzene isomers into m-diisopropylbenzene is vary valuable.It has been reported that β zeolite molecular sieve has good catalytic properties for diisopropylbenzene isomerization.This paper first studied the influence of the catalyst preparation method on catalyst performance, the result showed that dealing with citric acid one time is good. Moreover, in the preparation, extrusion before acid modification can get higher activity. The amount of binder must not be excessive, otherwise, this will also affect the catalyst activity, and binder SB powder is superior to Al2O3. Second, the influence of different reaction conditions on the isomerization were investigated. The result showed that, under pressure of3.2MPa, the optimum reaction temperature is195℃, the best WSHV is1.0h-1. Then, under this condition, we carried out series of8hours,50hours and100hours continuous experiments to varify the best conditions. At the same time, the result also showed that o-DIPB content of product is about0.5%, o-DIPB/m-DIPB is about1%, both can achieve the requirements of the post-deparation. Adding benzene to raw materials can not only ensure the catalyst activity and stability, but also reduce the content of recombinant in product. This way saves energy and material consumption, protect envirroment, so it is more conductive to industrial production. Finally, we carried out this experiment in a pilot and made preparations for the future of industrialization.