Synthetic method of m-dichlorobenzene

Abstract

The invention discloses a synthetic method of m-dichlorobenzene which is obtained by transposition in the presence of a catalyst by taking o-dichlorobenzene and/or p-dichlorobenzene as raw materials. The catalyst is a composite catalyst comprising a solid phase catalyst and a gas phase catalyst, wherein the solid phase catalyst is aluminum trichloride or halide of transition metal, and the gas phase catalyst is anhydrous hydrogen chloride or other anhydrous halogen acids. The raw materials have no limitation of water, have arbitrary ortho-para proportion and react under normal pressure; the solid catalyst has long service life, and the gas catalyst can be recycled after gas-liquid separation and has high conversion ratio; and the synthetic method can be used for large-scale industrial production. The process realizes the automatic control easily and has energy saving, safety, environment protection and low cost.

Description

Technical field: [0001] The invention relates to a synthesis method of m-dichlorobenzene. Background technique: [0002] m-dichlorobenzene is a basic organic chemical raw material. As one of the important raw materials for pesticides, pharmaceuticals and dye intermediates, its market prospect is quite broad. [0003] Since chlorine is an ortho- and para-positioning group, usually the chlorination of benzene to dichlorobenzene is a mixture of three isomers, o-, p-, and meta-isomers, which also contains a small amount of trichlorobenzene. In the mixed solution, due to the difference in the types of catalysts used, the ratio of the ortho-position and the para-position can be adjusted, but the ratio of m-dichlorobenzene is about 3%. Among the three isomers, m-dichlorobenzene is relatively more valuable because it is difficult to obtain and has a wide range of uses. In order to ensure accurate positioning, m-nitrochlorobenzene or m-dinitrobenzene is usually thermally chlorinate...

AI Technical Summary

Problems solved by technology

[0008] ① Transposition under normal pressure in the presence of water can only be operated intermittently, and the product is a mixture of three isomers, ortho, meta, and para, with low conversion and complicated separation;