Production method and production system for 2,4-dichlorophenol

Abstract

The invention provides a production method for 2,4-dichlorophenol. The production method comprises the following steps: S1) mixing an initiator, phenol and a catalyst and carrying out a reaction to obtain the chlorination tail gas of phenol and a reaction solution, wherein the initiator is sulfuryl chloride; S2) mixing the chlorination tail gas of phenol with chlorine gas for a reaction to obtainsulfuryl chloride; and S3) mixing the sulfuryl chloride with the reaction solution and carrying out a reaction to obtain the chlorination tail gas of phenol and 2,4-dichlorophenol. Compared with the prior art, the invention has the following advantages: chlorine gas is used as an initial chlorination raw material and continuously produces sulfuryl chloride through a reaction with sulfur dioxide inthe chlorination tail gas of phenol, and then the sulfuryl chloride is continuously added into the reaction solution to finally prepare 2,4-dichlorophenol; continuous reaction and tail gas recyclingflow are adopted in the invention, so high-selectivity low-cost high-yield preparation of 2,4-dichlorophenol is realized; moreover, the production method is simple in process flow and applicable to industrial production, and has great economic value and social benefits.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, in particular to a production method and production system of 2,4-dichlorophenol. Background technique [0002] 2,4-Dichlorophenol is used as a solvent, pesticide and pharmaceutical intermediate for the synthesis of biben, 2,4-D, ibifos (EPBP), dukesan, glyphosate and the drug thiobisdichlorophene, The annual demand is tens of thousands of tons. [0003] The production methods of 2,4-dichlorophenol mainly include: phenol direct chlorination method, mixed phenol chlorination method, o-chlorophenol selective chlorination method, p-chlorophenol chlorination method and phenol catalytic chlorination method. [0004] The direct chlorination of phenol is a traditional production process at home and abroad. The process is simple and the cost is low. However, because the physical properties of the by-product 2,6-dichlorophenol are very close to those of 2,4-dichlorophenol, it is difficult to se...

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Problems solved by technology

[0010] The Chinese patent with the publication number CN105777499A discloses a method for directional synthesis of 2,4-dichlorophenol and 2,4,6-trichlorophenol with sulfuryl chloride plus a composite catalyst. It is mentioned that 98% of 2, 4-dichlorophenol, but due to the use of expensive sulfuryl chloride, and the subsequent use of molten crystallization for separation, it will inevitably lead to the mixing of low-melting catalysts and oxidative and discolored substances during chlorination into the target product, resulting in poor appearance of the product and containing Certain impurities will affect subsequent use and make it difficult to implement industrialization

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