Research On βZeolite Catalyst For Reaction Of Aromatics Alkylation

Isopropenyl Toluene (IPT) Is an important chemical raw materials. P-cymene and M-cymene are the midbodies to product p-cresol and m-cresol. In order to meet the demand of the raw material, the mass fraction of ortho-isomeride should less than3.5%.So it is necessary to reduce ortho isomer content of isomerization adjacen. Removing isomerization unit operation which is required to industrialization can save construction investment, reduce material consumptions and energy consumption. So far, with the rise of isopropyl toluene market demand at home and abroad, the production of isopropyl toluene got rapid development. There are serious equipment corrosion and environmental pollution problems when AlC13is used as the main catalyst In the production of isopropyl toluene in our country. A new type of non-toxic, no pollution, highly active catalyst which can substitute for AlC13is one of the industrial development requirements.AlC13is used as catalyst in the commercial production, the product ratio of the O-isopropyl toluene, M-isopropyl toluene and P-isopropyl toluene are3:64:33. Then using phosphoric acid/diatomite as a catalyst, the quality ratio of the O-isopropyl toluene, M-isopropyl toluene and P-isopropyl toluene are44:23:33. Compared with the traditional catalysts, because the production cost is low, the catalyst have good stability, simple separation recycling, no equipment corrosion and environmental pollution etc, zeolite molecular sieve catalyst shows a wide prospect of industrial application. This paper adopts tubular fixed bed reactor and conducts continuous reaction. We surveyed the process conditions of preparation of isopropyl toluene based on Beta zeolite, including the best reaction temperature, space velocity, raw stuff mole ratio and the influence of different modification on the catalyst. Effect of phosphoric acid supported on activated carbon to three isomers of isopropyl toluene was researched.Beta molecular sieve, after a load of a certain quality of titanium sulfate, has the highest reactivity; the actual conversion rate of toluene is obvious rise, but O-isopropyl toluene selectivity increases. Loading after the extrusion molding can improve the activity of catalyst and save time in the process of mass production in the factory. In catalyst stability tests, the results of toluene conversion was stable, M-isopropyl toluene selectivity remains at around74%, selectivity of O-isopropyl toluene remains around4%.Through many experiments, the best reaction process conditions and the catalyst preparation process were determined. The results show that Beta molecular sieve of the load mass fraction of6%titanium sulfate has the optimal catalytic performance. In the experiment of alkylation of toluene by Propylene on beta molecular sieve, the suitable condition is: temperature220℃, the amount of toluene and propylene material ratio of7.75:1. the aualitv of space velocity of3.4h-1.