Preparation method of 2-trifluoromethyl benzoic acid

A technology of trifluoromethylbenzoic acid and trifluoromethyldichlorobenzyl, which is applied in the field of preparation of 2-trifluoromethylbenzoic acid, can solve problems such as expensive, harsh reaction conditions, harmful to human body and environment, and achieve catalyst Less dosage, high fluorination yield and good selectivity

Active Publication Date: 2013-09-04
KINGCHEM LIAONING CHEMICAL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

CN102516047A describes the use of antimony trichloride, antimony pentachloride or antimony trifluoride as a catalyst to complete the fluorination reaction. This type of heavy metal catalyst is harmf

Method used

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  • Preparation method of 2-trifluoromethyl benzoic acid
  • Preparation method of 2-trifluoromethyl benzoic acid
  • Preparation method of 2-trifluoromethyl benzoic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] Embodiment 1: In a 5L stainless steel autoclave equipped with a stirrer and a thermometer, cool down to below 5°C, add hydrogen fluoride and 2-trichloromethyl benzyl dichloride in sequence, and the mass ratio of the two is 0.2:1, and then Add the catalyst perfluorooctanesulfonyl fluoride, the mass ratio of 2-trichloromethyl benzyl dichloride to the catalyst is 1:0.001, raise the temperature to 80-90°C, control the reaction pressure to 2.5-2.8MPa, and react for 4 hours. Sampling and GC detection showed that the content of the intermediate product 2-difluorochloromethyl benzyl dichloride was 0.3%. After the reaction is completed, excess hydrogen fluoride is removed by purging with nitrogen, and neutralized to pH=6-7 with potassium carbonate aqueous solution. After standing still, the product 2-trifluoromethyl benzyl dichloride was isolated with a content of 96.6% and a yield of 94.1%.

[0052] The reaction formula for fluorination is:

[0053]

[0054] The fluorinati...

Embodiment 2

[0059]Embodiment two: in the 5L stainless steel autoclave that is equipped with stirrer, thermometer, cool down to below 5 ℃, add hydrogen fluoride and 2-trichloromethyl benzyl dichloride successively, and the mass ratio of the two is 1: 1, then Add the catalyst perfluorobutylsulfonyl fluoride, the amount of 2-trichloromethyl benzyl dichloride and the catalyst is 1:0.01, raise the temperature to 50-60°C, control the reaction pressure 0.8-1.2MPa, and react for 4 hours. Sampling and GC detection showed that the content of the intermediate product 2-difluorochloromethyl benzyl dichloride was 0.2%. After the reaction is completed, excess hydrogen fluoride is removed by purging with nitrogen, and neutralized to pH=6-7 with potassium carbonate aqueous solution. After standing still, the product 2-trifluoromethyl benzyl dichloride was isolated with a content of 97.5% and a yield of 93.5%.

[0060] The reaction formula for fluorination is:

[0061]

[0062] The fluorination react...

Embodiment 3

[0067] Embodiment three: in the 5L stainless steel autoclave that is equipped with stirrer, thermometer, cool down to below 5 ℃, add hydrogen fluoride and 2-trichloromethyl benzyl dichloride successively, and the mass ratio of the two is 0.5: 1, then Add a catalyst, the catalyst is composed of a mixture of perfluoropentylsulfonyl fluoride, perfluoroheptylsulfonyl fluoride and perfluorooctylsulfonyl fluoride, the amount of 2-trichloromethyl benzyl dichloride and the catalyst is 1:0.005, and the temperature rises To 140-150°C, control the reaction pressure to 4.5-5.0MPa, and react for 4 hours. Sampling and GC detection showed that the content of the intermediate product 2-difluorochloromethyl benzyl dichloride was 0.5%. After the reaction is completed, excess hydrogen fluoride is removed by purging with nitrogen, and neutralized to pH=6-7 with potassium carbonate aqueous solution. After standing still, the product 2-trifluoromethyl benzyl dichloride was isolated with a content ...

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Abstract

The invention discloses a preparation method of 2-trifluoromethyl benzoic acid, which comprises the following steps of (1) allowing 2-trichloromethyl benzal chloride and anhydrous hydrogen fluoride to perform fluoridation under the condition of a catalyst, and obtaining 2-trifluoromethyl benzal chloride, and (2) allowing 2-trifluoromethyl benzal chloride to react with nitric acid, and obtaining a target compound, namely 2-trifluoromethyl benzoic acid after acid hydrolysis and oxidation reactions. The preparation method has the advantages that the catalyst adopts a low-toxicity and safe agent; other solvents are not required to be added to the fluoridation; an excessive hydrogen fluoride solution is utilized to help dissolution; the hydrolysis and oxidation reactions take nitric acid as a reaction agent, so that toxic gas and toxic substances generated after the reactions are reduced; and nitric acid utilized by hydrolysis and oxidation can be circulated for many times and recycled after fuming nitric acid with the calculated amount is added and a concentration of nitric acid is adjusted.

Description

technical field [0001] The invention belongs to the technical field of synthesis methods of chemical products, in particular to a preparation method of 2-trifluoromethylbenzoic acid. Background technique [0002] 2-Trifluoromethylbenzoic acid was used in the synthesis of a novel broad-spectrum fungicide fluopyram. The chemical name of the fungicide is: N-{2-[3-chloro-5-(trifluoromethyl)-2-pyridine]ethyl}-2-(trifluoromethyl)benzamide, which can be used for grape , pome and stone fruits, vegetables, disease control of field crops. Its molecular structural formula is as shown in formula (II): [0003] [0004] The structure of the part inside the dotted line of the molecule is derived from 2-trifluoromethylbenzoic acid (I). [0005] Through literature research, 2-trifluoromethylbenzoic acid (I) has following several synthetic routes: [0006] method 1: [0007] WO2011021492A 1 A process for the preparation of 2-trifluoromethylbenzaldehyde and its derivatives by hydroly...

Claims

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Application Information

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IPC IPC(8): C07C63/70C07C51/27
Inventor 付立民
Owner KINGCHEM LIAONING CHEMICAL CO LTD
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