Method of preparing 2, 4, 5-trifluorobenzoic acid by microstructural reactor

A microstructure reactor, the technology of trifluorobenzoic acid, which is applied in the preparation of carboxylate, the preparation of carboxylate/lactone, organic chemistry, etc., can solve the problem of inability to realize continuous operation, difficult mass production, and many reaction steps, etc. problem, to achieve the effect of no amplification effect, continuous process, mild reaction conditions

Inactive Publication Date: 2014-08-20
NANJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In the existing patented technologies, most of them adopt the operation mode of low temperature and dropwise addition, the reaction fl...

Method used

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  • Method of preparing 2, 4, 5-trifluorobenzoic acid by microstructural reactor

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Embodiment 1

[0023] Ethylmagnesium bromide tetrahydrofuran solution (1M) and 2,4,5-trifluorobromobenzene tetrahydrofuran solution (1M) were injected into micro-mixer B1 (cross-toed micro Mixer, HPIMM, IMM, Germany, length × width × height = 25 × 21 × 37 μm) mixed, then enter the microchannel reactor C1 (inner diameter: 1mm) and carry out Grignard exchange at the temperature of the incubator D1 (10°C) And react for 2min, the product 2,4,5-trifluorophenylmagnesium bromide is metered into CO by F 2 The gas enters the micro-mixer B2 (V2, IMM, Germany, width × depth = 45 × 200 μm) according to the flow rate ratio of 1:10, and then enters the microchannel reactor C2 (inner diameter: 1mm), and continues in the incubator D2 (10°C) Carry out nucleophilic addition at high temperature and react for 0.5min, pump the product collection bottle E pre-filled with ammonium chloride aqueous solution and diethyl ether by plunger pump A3, add glacial acetic acid solution to the collection bottle E under stirr...

Embodiment 2

[0025] Ethylmagnesium bromide tetrahydrofuran solution (0.5M) and 2,4,5-trifluorobromobenzene tetrahydrofuran solution (0.5M) were injected into micro-mixer B1 (cross-toed Type micro-mixer, HPIMM, IMM, Germany, length × width × height = 25 × 21 × 37μm), enter the microchannel reactor C1 (inner diameter: 1mm) and continue to carry out the grid at the temperature of the incubator D1 (20°C). Exchange and react for 5min, the product 2,4,5-trifluorophenylmagnesium bromide and CO 2 The gas flow rate ratio is 1:20 and enters the falling film microstructure reactor B2 (length × width: 300 × 100μm) for mixing, then enters the microchannel reactor C2 (inner diameter: 2mm), and continues to carry out at the temperature of the incubator D2 (20°C) Nucleophilic addition and reaction for 5 minutes, pumped by plunger pump A3 into the product collection bottle E pre-installed with ammonium chloride aqueous solution and ether, adding sulfuric acid solution to the collection bottle E under stirr...

Embodiment 3

[0027] Ethylmagnesium bromide tetrahydrofuran solution (1.5M) and 2,4,5-trifluorobromobenzene tetrahydrofuran solution (1.5M) were injected into micro-mixer B1 (cross-toed Type micro-mixer, HPIMM, IMM, Germany, length × width × height = 25 × 21 × 37μm) and then enter the microchannel reactor C1 (inner diameter: 1mm) to continue at the temperature of the incubator D1 (40°C) Grignard exchange and reaction for 8 minutes, the product 2,4,5-trifluorophenylmagnesium bromide and CO 2The gas enters the falling film microstructure reactor B2 (length×width: 300×100μm) at a flow rate ratio of 1:25, and then enters the microchannel reactor C2 (inner diameter: 3mm), and continues to be heated at the temperature of the incubator D2 (30°C). Carry out nucleophilic addition and react for 10 minutes, pump into the product collection bottle E pre-installed with ammonium chloride aqueous solution and diethyl ether by plunger pump A3, add hydrochloric acid solution in the collection bottle E under...

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Abstract

The invention provides a method of preparing 2, 4, 5-trifluorobenzoic acid by a microstructural reactor. The method comprises the following steps: by taking 2, 4, 5-trifluorobromobenzene as a raw material, carrying out Grignard exchange with a Grignard reagent to obtain 2, 4, 5-trifluorophenyl magnesium bromide; and under a continuous flow condition, carrying out a nucleophilic addition on the generated 2, 4, 5-trifluorophenyl magnesium bromide and a gas CO2 to prepare the 2, 4, 5-trifluorobenzoic acid. The method provided by the invention has the characteristic of continuously and quickly preparing 2, 4, 5-trifluorobenzoic acid, is controllable in process and good in product selectivity and can realize industrialized production.

Description

technical field [0001] The invention relates to a method for preparing 2,4,5-trifluorobenzoic acid, in particular to a rapid, efficient and continuous method for preparing 2,4,5-trifluorobenzoic acid using a microstructure reactor. Background technique [0002] 2,4,5-Trifluorobenzoic acid is an important raw material for the synthesis of medicines, dyes and herbicides, especially for the synthesis of fluoroquinolone antibacterials such as Clinfloxacin, which has attracted much attention. [0003] U.S. Patent No. 4,876,387 uses 4,5-difluoroanthranilic acid as a raw material to react with an inorganic acid to obtain a corresponding inorganic acid salt, and then in NaNO 2 and HBF 4 Under the action, the corresponding diazonium salt can be generated by reaction, and finally 2,4,5-trifluorobenzoic acid can be obtained by pyrolysis. Chinese patent CN1746146 uses 2,4-dichloro-5-fluorobenzoyl chloride to generate 2,4,5-trifluorobenzoyl chloride through fluorination reaction, and t...

Claims

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Application Information

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IPC IPC(8): C07C63/70C07C51/09
CPCC07C51/02C07C51/09C07C63/70
Inventor 张利雄邓秋林沈如伟赵志敏严梅梅
Owner NANJING UNIV OF TECH
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