Preparation method of p-diethylbenzene catalyst by using high-efficiency alkylation of ethylbenzene

Abstract

The invention discloses a preparation method of a p-diethylbenzene catalyst by using high-efficiency alkylation of ethylbenzene, and belongs to the technical field of preparation of catalysts. The preparation method comprises the following steps of mixing a nanometer hydrogen type ZSM-5 molecular sieve, an adhesive and an extrusion additive; adding an inorganic acid solution and modified components of magnesium and phosphor in the kneading process, mixing, peptizing, extruding, forming, and treating by hydrothermal aging, so as to improve the stability of the catalyst; impregnating the modified component of silicon in the carrier by one step, so as to obtain the catalyst, wherein the pore size of the molecular sieve of the catalyst and the acidity at the outer surface are modified, and thereaction property and stability are obviously improved under the synergistic modifying function of magnesium, silicon and phosphor. The preparation method has the advantages that compared with the prior art, the modified components of magnesium and phosphor can be directly lead in the strip extruding process, so that the preparation process is simplified, and the industrial production cost is reduced; after the prepared catalyst is evaluated by a fixed bed miniature reaction device in a laboratory, the selectivity on p-diethylbenzene reaches 98.5%, the conversion rate of ethylbenzene reaches20%, and the stable running period is 350h.

Description

technical field [0001] The invention relates to the technical field of catalyst preparation, in particular to a preparation method of a catalyst for efficiently alkylating ethylbenzene to produce p-diethylbenzene. Background technique [0002] P-diethylbenzene is an essential analytical agent in the process of adsorption and separation of p-xylene, and its synthesis has very important social benefits and practical value. The industry requirement for p-diethylbenzene as a p-xylene desorbent is that its purity is greater than 95%. However, due to the similar boiling points of p-diethylbenzene, o-diethylbenzene and m-diethylbenzene, the rectification method is used to purify p-diethylbenzene products from mixed diethylbenzene (p-diethylbenzene content 30%), and the separation energy consumption is high , the purity is also difficult to meet the requirements. At present, the industrial production of p-diethylbenzene generally adopts the catalyst with HZSM-5 as the main body, a...

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Problems solved by technology

The catalyst prepared by this method has a selectivity of 95-98% to diethylbenzene in the alkylation reaction of ethyl phenylethanol, but the conversion rate of ethylbenzene is low (only 5-10%), and the performance in practical application The resulting catalyst has poor regeneration repeatability and is not suitable for industrial applications

[0005] CN200410020397.7 discloses a method for synthesizing p-diethylbenzene by the alkylation reaction of ethylbenzene and ethanol, using the HZSM-5 molecular sieve with SiO2 / Al2O3=100 as the matrix, and using components such as boron, magnesium and cobalt on the molecular sieve Surface acidity and pore structure are adjusted, and the obtained catalyst is at 370 ℃, the molar ratio of ethylbenzene and ethanol is 2: 1, when reacting for 10 hours, although the selectivity to diethylbenzene is close to 100%, the initial activity of ethylbenzene is not high. High, so that the yield of diethylbenzene is only 14%; and the mol ratio of ethylbenzene and ethanol reaches 2: 1, makes the utilization rate of ethanol lower

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