Method of separating and purifying o/p-dihydroxy benzene prepared by phenol hydroxylation

Abstract

The invention relates to a separation and purification method of catechol and hydroquinone prepared by hydroxylation reaction of phenyl hydrate with hydrogen peroxide, wherein the product consists of water, phenyl hydrate, pyrocatechol, p-dihydroxy benzene and tar. The separation and purification method of present invention principally includes the following steps: transmitting resultant of reaction into normal pressure leading tower, and water solution containing phenols on tower top partially entering extraction column for reclaiming phenyl hydrate; the liquid of leading tower passing though de-phenol main tower, de-phenol auxiliary tower in sequence and tower top fraction of auxiliary tower returning main tower; the liquid of de-phenol auxiliary tower passing through pyrocatechol fractionating tower and p-dihydroxy benzene fractionating tower and then obtaining producers of pyrocatechol and p-dihydroxy benzene whose purity is more than 99% in sequence, at last the tar discharged from decoking tower.

Description

technical field [0001] The present invention relates to the separation and purification method of the reaction product of o- / hydroquinone prepared by hydroxylation of phenol and hydrogen peroxide, specifically dehydrating the phenol hydroxylation reaction solution, extracting phenol, rectifying and separating catechol and hydroquinone A series of separation processes such as diphenol and tar removal can achieve the purpose of recovering unreacted raw material phenol, and separating and purifying catechol and hydroquinone products. technical background [0002] Catechol and hydroquinone are two important fine chemical products with a wide range of applications. Catechol, also known as catechol, is a basic organic raw material or intermediate in industries such as pesticides, medicines, spices, rubber, dyes, and photosensitive materials. In the pesticide industry, it is an important intermediate for the production of carbofuran, ethylfencarb, and propoxur; it is used in the m...

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Problems solved by technology

In this process flow, the secondary dephenolization is placed before detarring. Although the energy consumption of the process is lower than that of the Rhone Planck Company, it still increases the energy consumption of decatechol compared with the final detarring process; the dehydration tower Using decompression operation, the tower diameter is several times larger than that of the atmospheric tower, and the equipment manufacturing and maintenance costs are high; in the process, the deep steamer is used to extract the remaining hydroquinone in the tar, and the discharged tar still contains more hydroquinone. Hydroquinone; the hydroquinone product discharged from the product tower still needs subsequent decolorization treatment even if the purity reaches more than 99%.

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