Air catalytic oxidation hydrogen bromide method for preparing 2,3,5-tribromo thiophene

Abstract

The invention relates to an air catalytic oxidation hydrogen bromide method for preparing 2,3,5-tribromo thiophene. The air catalytic oxidation hydrogen bromide method is characterized by including the following specific steps: chloroform or petroleum ether, thiophene and cupric bromide or sodium nitride or iron bromide or cobalt bromide or ruthenium bromide are put into a reaction kettle (1) to be stirred, wherein the volume ratio of the chloroform or the petroleum ether to the thiophene is 2 to 1, and the cupric bromide or the sodium nitride or the iron bromide or the cobalt bromide or the ruthenium bromide comprises, by mass, 1% of thiophene; then bromine is dropwise added into the reaction kettle (1) through a first dropwise-adding tank (6) for reacting, and cooling is carried out; then an 0.05-mol / L-sodium-hydroxide ethanol solution with the volume a half of the volume of the bromine is dropwise added into the reaction kettle (1) through a second dropwise-adding tank (7); the reaction mixture is placed into a water washing kettle (2), water with the volume the same as the volume of the chloroform or the petroleum ether is added, sufficient stirring and standing are carried out, the mixture in the organic phase is charged into a distillation kettle (3) for atmospheric distillation, solvents and front cut fractions are recycled into a solvent recycling tank (4), then reduced pressure distillation is carried out, and 112-DEG C-116-DEG C / 15 mmHg cut fractions are collected into a product collecting tank (5) to obtain the colorless liquid 2,3,5-tribromo thiophene. The air catalytic oxidation hydrogen bromide method is low in production cost and small in environment pollution, and the bromine use rate is higher than 85%.

Description

technical field [0001] The invention relates to a method for producing 2,3,5-tribromothiophene, in particular to a method for preparing 2,3,5-tribromothiophene by air catalytic oxidation of hydrogen bromide. Background technique [0002] 2,3,5-Tribromothiophene is an important organic intermediate, mainly used in the synthesis of 3-bromothiophene, and 3-bromothiophene, as a derivative of β-thiophene, is used in the synthesis of thiophene polymers and the synthesis of new drugs, etc. It has important application value. 2,3,5-tribromothiophene is a very important fine chemical raw material, and its synthesis method is mainly to synthesize 2,3,5-tribromothiophene by reacting thiophene with bromine under the catalysis of a catalyst. The main problems are: 1) bromine utilization rate in the synthesis of 2,3,5-tribromothiophene from brominated thiophene; 2) recovery and reuse of by-product hydrogen bromide in brominated thiophene; 3) 2,3 , The separation and purification of 5-tr...

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Problems solved by technology

The main problems are: 1) bromine utilization rate in the synthesis of 2,3,5-tribromothiophene from brominated thiophene; 2) recovery and reuse of by-product hydrogen bromide in brominated thiophene; 3) 2,3 , the separation and purification of 5-tribromothiophene; 4) the recovery and utilization of bromine, hydrogen bromide, inorganic salts and thiophene in waste gas and wastewater during the synthesis of 2,3,5-tribromothiophene from brominated thiophene

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