Green synthesis method for p-iodotoluene

A green synthesis technology of p-iodotoluene, applied in chemical instruments and methods, preparation of halogenated hydrocarbons, disproportionation separation/purification of halogenated hydrocarbons, etc., can solve problems such as high price, hidden dangers of production safety, unfavorable large-scale industrial production, etc. Achieve high yield and reduce production cost

Active Publication Date: 2020-03-31
SHAANXI UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
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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 c

Method used

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  • Green synthesis method for p-iodotoluene

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Effect test

Embodiment 1

[0032] To a 500mL four-neck flask equipped with a thermometer and a reflux condenser, add 100mL of formic acid aqueous solution with a volume concentration of 20%, 0.2mol (18.4g) of toluene, 0.2mol of hydrogen peroxide, 0.2mol (30g) of sodium iodide and 1.84g of perfluorinated For sulfonic acid resin, turn on the heating, adjust the reaction temperature so that the reaction solution is in a reflux state until the color of the reaction solution changes from purple to colorless, stop the reaction, and recover the perfluorosulfonic acid resin through centrifugation or filtration of the reacted mixed solution, centrifuge Or after filtration, the filtrate is subjected to a multi-stage extraction-flash evaporation-low temperature crystallization process to sequentially separate formic acid aqueous solution, unreacted toluene and product p-iodotoluene, and the yield of p-iodotoluene is 81%.

Embodiment 2

[0034] To a 500mL four-necked flask equipped with a thermometer and a reflux condenser, add 100mL of 30% acetic acid aqueous solution, 0.2mol (18.4g) toluene, 0.1mol potassium persulfate compound salt, 0.1mol (15g) sodium iodide in sequence and 18.4g perfluorosulfonic acid resin, turn on the heating, adjust the reaction temperature so that the reaction solution is in a reflux state, until the color of the reaction solution changes from purple to colorless, stop the reaction, and the reacted mixed solution is recovered by centrifugation or filtration. Sulfonic acid resin, after centrifugation or filtration, the filtrate is subjected to multi-stage extraction-flash evaporation-low temperature crystallization process, and the acetic acid aqueous solution, unreacted toluene and product p-iodotoluene are separated in sequence. After testing, the yield of p-iodotoluene is 86%.

Embodiment 3

[0036] To a 500mL four-neck flask equipped with a thermometer and a reflux condenser, add 100mL of 30% propionic acid aqueous solution, 0.2mol (18.4g) toluene, 0.15mol ammonium persulfate, 0.1mol (16.6g) potassium iodide and 184g all Fluorosulfonic acid resin, turn on the heating, adjust the reaction temperature to keep the reaction solution in a reflux state, until the color of the reaction solution changes from purple to colorless, stop the reaction, and recover the perfluorosulfonic acid resin by centrifuging or filtering the reacted mixed solution. After centrifugation or filtration, the filtrate is subjected to multi-stage extraction-flash evaporation-low temperature crystallization process, and the propionic acid aqueous solution, unreacted toluene and product p-iodotoluene are sequentially separated. After testing, the yield of p-iodotoluene is 78%.

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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 ...

Claims

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Application Information

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IPC IPC(8): C07C17/12C07C25/02C07C17/38
CPCC07C17/12C07C17/38C07C25/02
Inventor 李小龙赵卓雅马永宁杨雨豪孙丽媛常雨情张月茹魏天柱
Owner SHAANXI UNIV OF SCI & TECH
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