Preparation method of 2,3,4,5-tetrafluorobenzoyl chloride
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A technology of tetrafluorobenzoyl chloride and tetrafluorobenzoic acid is applied in the field of preparation of 2,3,4,5-tetrafluorobenzoyl chloride, and can solve the problems of complicated operation process, long production cycle, and many product losses, etc., To achieve the effect of simplifying the operation process, reducing production time and avoiding product loss
Active Publication Date: 2012-07-25
ZHEJIANG ZHONGXIN FLUORIDE MATERIALS CO LTD
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Problems solved by technology
The above-mentioned preparation process has cumbersome operation process, troublesome solvent recovery and application, long production cycle, high energy consumption, low production efficiency, and more product loss in the post-processing process, which greatly restricts2,3,4,5 -Increasing production and reducing consumption of tetrafluorobenzoyl chloride
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Embodiment 1
[0028] Add 47.6 grams of 3,4,5,6-tetrafluorophthalic acid (I), 285 grams of trimethylbenzene, and 1.5 grams of tri-n-propylamine into a 500 mL three-necked flask equipped with mechanical stirring, a thermometer, and a condenser, and stir to raise the temperature to 150 o C, reacted for 15 hours, and the reaction system was cooled to 20-30 o C, filtered to obtain 39.5 g of crude 2,3,4,5-tetrafluorobenzoic acid (II), and the filtrate was used for the next batch of decarboxylation reaction.
Embodiment 2
[0030] Add 47.6 grams of 3,4,5,6-tetrafluorophthalic acid (I) and 1.5 grams of tri-n-propylamine into a 500 mL three-necked flask equipped with mechanical stirring, a thermometer, and a condenser, and add the recovered Trimethylbenzene, and add trimethylbenzene to 285 grams, stir and heat up to 150 o C, reacted for 15 hours, and the reaction system was cooled to 20-30 o C, filtered to obtain 42.2 g of crude 2,3,4,5-tetrafluorobenzoic acid (II), and the filtrate was used for the next batch of decarboxylation reaction.
Embodiment 3
[0032] Add 35.7 grams of 3,4,5,6-tetrafluorophthalic acid (I), 320 grams of xylene, and 1.5 grams of tri-n-butylamine into a 500 mL three-neck flask equipped with mechanical stirring, a thermometer, and a condenser, and stir Warm up to 135 o C, reacted for 22 hours, and the reaction system was cooled to 20-30 o C, filtered to obtain 30.3 g of 2,3,4,5-tetrafluorobenzoic acid (II), and the filtrate was used for the next batch of decarboxylation reaction.
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Abstract
The invention discloses a preparation method of 2,3,4,5-tetrafluorobenzoyl chloride, belonging to the technical field of chemical synthesis. The preparation method comprises the following step: performing a reaction of a raw material 3,4,5,6-tetrafluorophthalic acid in a solvent of aromatic hydrocarbon in the presence of a catalytic amount of organic tertiary amine at a temperature of 120-160 DEG C until the content of the raw material is less than 1%, cooling the reaction system to 20-30 DEG C, filtering, wherein an obtained filtrate is used for a next batch of decarboxylic reaction, adding an acyl chlorination reagent and an organic amide catalyst into the filtered solid of 2,3,4,5-tetrafluorobenzoic acid, heating and reacting until the content of 2,3,4,5-tetrafluorobenzoic acid is less than 0.5%, evaporating and removing low-boiling-point substances of the reaction system, and preforming rectification under vacuum to obtain the finished product of 2,3,4,5-tetrafluorobenzoyl chloride. The preparation method disclosed by the invention has the advantages of being simple in steps, high in production efficiency and synthetic efficiency and the like.
Description
Technical field: [0001] The present invention relates to a kind of preparation method of 2,3,4,5-tetrafluorobenzoyl chloride, specifically, relate to a kind of preparation method of 2,3,4 by 3,4,5,6-tetrafluorophthalic acid , The method for 5-tetrafluorobenzoyl chloride belongs to the technical field of chemical synthesis. Background technique: [0002] 2,3,4,5-Tetrafluorobenzoyl chloride is an important pharmaceutical intermediate, widely used in the synthesis of third-generation fluoroquinolone antibacterial drugs, such as (left) ofloxacin, sparfloxacin , Lomefloxacin, Fleroxacin, etc., have broad market prospects. [0003] The industrial synthesis of 2,3,4,5-tetrafluorobenzoyl chloride mainly contains the following two routes: 1, using phthalonitrile as raw material, through chlorination, fluorination, hydrolysis, decarboxylation and acyl chloride reaction, to obtain 2 ,3,4,5-Tetrafluorobenzoyl chloride; 2. Using phthalic anhydride as raw material, through c...
Claims
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