Preparation method of shape-selective catalyst used for p-dialkyl benzene synthesis process

Abstract

The invention relates to a preparation method of a shape-selective catalyst used for a p-dialkyl benzene synthesis process, and relates to the technical field of preparation of a high-performance catalyst for an alkylation process. The preparation method comprises the steps of: weighing a metal nitrate, adding to absolute ethanol at a mass ratio of metal nitrate to absolute ethanol being 1:10 for completely dissolving, then adding a complex ligand at a molar ratio of the complex ligand to metal ions in the metal nitrate being (1:1)-(3:1), uniformly stirring, adding a microporous molecular sieve at a mass ratio of the metal ions in the metal nitrate to the microporous molecular sieve being (1:100)-(1:10), uniformly stirring, standing at room temperature for 24h, drying in a 60 DEG C water bath, then transferring to an oven, drying at 120 DEG C for 6h, baking in a muffle furnace, heating to 550 DEG C at a speed of 10 DEG C/min, and maintaining the temperature for 6h to obtain the required shape-selective catalyst. The preparation method is simple and low in cost; and the obtained shape-selective catalyst has high shape selective performance.

Description

technical field [0001] The invention relates to the technical field of preparing a high-performance catalyst in an alkylation process, in particular to a preparation method for a shape-selective catalyst in the process of synthesizing p-dialkylbenzene. Background technique [0002] P-dialkylbenzenes such as p-xylene and p-diethylbenzene are important chemical raw materials, and their traditional synthesis methods are mainly obtained through the disproportionation process of toluene or ethylbenzene, but because the disproportionation process requires a strong acidic catalyst and a high The reaction temperature is higher, so the catalyst deactivation is faster. In recent years, the synthesis of p-xylene and p-diethylbenzene by direct alkylation of toluene or ethylbenzene has become a research hotspot. [0003] The commonly used catalysts in the alkylation process of toluene and ethylbenzene are microporous molecular sieves such as ZSM-5 or MCM-22. The alkylation reaction can ...

AI Technical Summary

Problems solved by technology

Although the method of silicon deposition can effectively improve the shape-selective performance of molecular sieve catalysts, due to the weak force between the hydroxyl groups on the surface of molecular sieves and the sediments, it often takes 3-4 times of deposition to achieve better results, so the operation is more cumbersome , higher energy consumption

Pre-coking can also improve the shape-selective performance of molecular sieve catalysts, but since the regenerated catalyst must be pre-coked again, the operation is cumbersome, and it is currently limited to laboratory research

It is very simple to use metal oxide modification to cover the acid sites on the outer surface of molecular sieves, and a good covering effect can be achieved in one operation. Can be used on a large scale