Vanadium-pyridine catalyst for preparing 2, 5-dichlorophenol through catalytic oxidation and synthesis method and application of vanadium-pyridine catalyst

Abstract

The invention discloses a vanadium pyridine catalyst for preparing 2, 5-dichlorophenol through catalytic oxidation and a synthesis method and application of the vanadium pyridine catalyst. The catalyst is a Py-V complex as shown in the following structural formula, and is prepared by dissolving pyridine-2, 6-dicarboxylic acid in methanol, adding vanadyl acetylacetonate, refluxing, filtering, washing, drying and the like. The operation steps are simple and easy to control, the yield is 60% or above in terms of vanadium, the whole synthesis process is short in time consumption, and the method issuitable for industrial production. In the process of preparing 2, 5-dichlorophenol through catalytic oxidation of 1, 2, 4-dichlorobenzene, the Py-V complex is adopted as a catalyst, the excessive oxidation of 2, 5-dichlorophenol can be effectively inhibited while the catalytic efficiency is improved, the excessive oxidation product can be controlled to be 10% or below, the selectivity of 2, 5-dichlorophenol reaches 90% or above, and the oxidation reaction efficiency and yield are obviously improved.

Description

technical field [0001] The invention belongs to the technical field of 2,5-dichlorophenol preparation, and in particular relates to a vanadium pyridine catalyst for preparing 2,5-dichlorophenol by catalytic oxidation of 1,4-dichlorobenzene, a synthesis method and an application thereof. Background technique [0002] 2,5-Dichlorophenol is an important intermediate of pesticides, medicines, dyes, nitrogen fertilizer synergists and leather antifungal agents. The pure product of 2,5-dichlorophenol is a white needle-like crystal with a special odor, and is currently mostly used in the synthesis of the herbicide 3,6-dichloro-2-methoxybenzoic acid (dicamba). [0003] At present, there are two main technological routes for preparing 2,5-dichlorophenol, namely, the hydrolysis method of 1,2,4-trichlorobenzene and the hydrolysis method of 2,5-dichloroaniline diazo. As proposed in the patent US2799714, 1,2,4-trichlorobenzene is used as a raw material to prepare mixed dichlorophenol und...

AI Technical Summary

Problems solved by technology

However, the catalytic effect is not ideal and the product selectivity is low

Such as Chinese patent CN107129426A discloses a kind of preparation method of 2,5-dichlorophenol, under the effect of oxidizing agent, metal porphyrin catalyst and cocatalyst, take 1,4-dichlorobenzene as raw material, water, methanol, acetonitrile, One or more than one composition in acetic acid is used as a solvent and prepared by catalytic oxidation; this method is to improve the efficiency and yield of the oxidation reaction through a catalytic system composed of a metalloporphyrin catalyst and a cocatalyst. It can be seen that it can be used alone Metalloporphyrin catalyst, catalytic effect is still unsatisfactory

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