Green synthesis method for p-iodotoluene

Abstract

The invention discloses a green synthesis method for p-iodotoluene, belonging to the technical field of synthesis of organic matters. According to the invention, perfluorosulfonic acid resin is adopted as a solid acid catalyst; due to a steric hindrance effect, the perfluorosulfonic acid resin mainly activates para-position hydrogen atoms of the p-iodotoluene; an oxidizing agent oxidizes iodine iniodized salt into iodine free radicals; the iodine free radicals attack the para-position activated hydrogen atoms of the p-iodotoluene; thus, a product, namely the p-iodotoluene is obtained. The green synthesis method provided by the invention has the following advantages: cheap and easily available toluene and iodized salt are used for respectively replacing expensive p-toluidine and periodic acid used in a conventional technology; meanwhile, reaction conditions are mild; after completion of the reaction, a solid catalyst, a carboxylic acid aqueous solution used as a reaction solvent and unreacted toluene can be recovered through centrifugation or filtration; the product, namely the p-iodotoluene is separated and recovered through a multi-stage extraction-flash evaporation-low-temperature crystallization process; and the green synthesis method provided by the invention has high yield, does not discharge three wastes in the preparation process, and is a green synthesis method.

Description

technical field [0001] The invention belongs to the technical field of organic compound synthesis, and in particular relates to a green synthesis method of p-iodotoluene. Background technique [0002] As an important intermediate of iodo derivatives, p-iodotoluene is widely used in the synthesis of related compounds in the fields of medicine, dyes, etc. -Phenyl-3-methyl-5-pyrazolone, etc. [0003] Existing synthesis methods about p-iodotoluene are mainly divided into two categories: one is to synthesize p-toluene with p-toluidine as benzene source, sodium iodate as iodine source, and phosphoric acid solution as reaction solvent (such as CN 105503511 A) , the benzene source-p-toluidine price that this kind of method adopts is comparatively expensive, and needs to add sodium carbonate solution to neutralize reaction solvent-phosphoric acid in reaction system after completion of reaction, makes phosphoric acid solution unable to reclaim, and the aftertreatment of waste liquid ...

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Problems solved by technology

[0003] Existing synthesis methods about p-iodotoluene are mainly divided into two categories: one is to synthesize p-toluene with p-toluidine as benzene source, sodium iodate as iodine source, and phosphoric acid solution as reaction solvent (such as CN 105503511 A) , the benzene source-p-toluidine price that this kind of method adopts is comparatively expensive, and needs to add sodium carbonate solution to neutralize reaction solvent-phosphoric acid in reaction system after completion of reaction, makes phosphoric acid solution unable to reclaim, and the aftertreatment of waste liquid further increases Industrial production cost; Another kind is with toluene as benzene source, with iodine and periodic acid as iodine source, with methyl tert-butyl ether as reaction solvent synthetic p-iodotoluene (as CN 101781157 B), although this class method adopts The relatively cheap benzene source—toluene is used, but part of the iodine source uses iodine simple substance that is easy to sublime and produces strong irritating and toxic fumes, and the other part uses expensive strong oxidizing perhalogen acid—periodic acid, Lead to the production safety hazard and high cost of the product—p-iodotoluene, which is not conducive to large-scale industrial production

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