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Process for preparing 2, 3, 5, 6-tetrafluoro-p-xylyl alcohol

A technology of methyl benzyl alcohol and tetrachloroterephthaloyl chloride is applied in the new preparation field, and can solve the problems of harsh reaction conditions, low total yield of methyl benzyl alcohol, unsuitable for industrial production, etc. The effect of convenient source, simple and reliable process operation and low production cost

Inactive Publication Date: 2005-06-01
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The used raw material 2 of this route, 3,5, the reagent used in 6-tetrafluorobenzene and synthetic such as methyl iodide, lithium aluminum hydride are expensive, are not suitable for industrialized production; It needs to be operated at a low temperature of -45°C, and high pressure is required for carbonylation, so that the total yield of 2,3,5,6-tetrafluoro-p-methylbenzyl alcohol is very low (only 1%) (GB2127013 1984-04-04)

Method used

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  • Process for preparing 2, 3, 5, 6-tetrafluoro-p-xylyl alcohol
  • Process for preparing 2, 3, 5, 6-tetrafluoro-p-xylyl alcohol
  • Process for preparing 2, 3, 5, 6-tetrafluoro-p-xylyl alcohol

Examples

Experimental program
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example 1

[0019] Preparation of 2,3,5,6-tetrafluoromethyl terephthalate

[0020] Mix 10g of anhydrous potassium fluoride powder, 100mL of sulfolane, 8.75g of tetrachloroterephthaloyl chloride, and 1g of calixarene catalyst into the reactor, heat up to 220°C, react at this temperature for 2 hours, then cool down to 20°C Below ℃, add 100mL of anhydrous methanol, and react at 60℃ for 6h. The esterified product was suction filtered to remove potassium fluoride and inorganic salts. After removing the solvent, the filtrate was added to about 50 mL of water to precipitate a precipitate, filtered with suction, washed with water, and dried to obtain 6.43 g of the product, with a yield of 93.87%. Product melting point: 72°C-74°C, liquid chromatography analysis product purity is 97.01%.

[0021] GC-MS analysis, MS: m / e (relative abundance, %), 266[M, 40], 235[M-OCH 3 , 100], 247 [M-F, 2].

[0022] IR analysis: 1726.4cm -1 , 1485.3cm -1 , 1217.2cm -1 .

example 2

[0024] Preparation of 2,3,5,6-tetrafluoro-tere-phenylene benzyl alcohol

[0025] 1.90g of sodium borohydride was dissolved in 30mL of diglyme, slowly added 5.00g of dimethyl tetrafluoroterephthalate dissolved in 10mL of diglyme was obtained by Example 1, Keep the temperature below 10°C and react for 12h. Extract with dichloromethane, lower the temperature to 0°C, wash with acid and alkali, and recover the solvent to obtain 2.76g of product with a melting point of 122°C to 124°C and a yield of 70.0%. The product has been identified by gas-mass spectrometry.

[0026] MS: m / e (relative abundance, %) 210[M, 100], 209[M-H, 25], 193[M-OH, 2], 189[M-F-2H, 50], 163[M-CH 2 OH-OH+H, 90], 145[M-CH 2 OH-F-OH+2H, 75].

example 3

[0028] Preparation of 2,3,5,6-tetrafluoro-p-bromomethyl benzyl alcohol

[0029] 1 g (4.8 mmol) of 2,3,5,6-tetrafluoro-p-dibenzyl alcohol obtained in Example 2 was added to 5 mL, 10 g (47 mmol) of 48% HBr acid, and 10 mL of benzene were added. The reaction mixture was heated and stirred at 65°C to 70°C for 2h. After the reaction mixture was cooled, the upper toluene layer was separated. After the toluene was dried with anhydrous magnesium sulfate, the toluene was recovered by rotary evaporation to obtain 0.7 g of a light yellow solid, with a yield of 54%. , identified by gas-mass spectrometry, liquid phase analysis of 94% purity.

[0030] The aqueous layer after separation of toluene was extracted with diethyl ether (2×10 mL), and 0.5 g of the raw material was obtained after distilling off the diethyl ether, which was recycled for reuse. The total yield is close to 100% based on raw material consumption.

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Abstract

The invention discloses a preparation method of 2,3,5,6-tetrafluoro-p-methylbenzyl alcohol, which belongs to the preparation technology of 2,3,5,6-tetrafluoro-p-methylbenzyl alcohol. The method is prepared by taking 2,3,5,6-tetrachloroterephthaloyl chloride as a raw material through fluorination, esterification, reduction, bromination and reduction. The fluorinating agent of the fluorination reaction is potassium fluoride, etc., the solvent is sulfolane, etc., the catalyst is calixarene, etc., and the reaction temperature is 40°C-230°C. Esterification The esterification agent is aliphatic alcohol or aromatic alcohol, and the reaction temperature is 20°C to 120°C. Reduction reaction of ester The reducing agent is sodium borohydride, etc., the solvent is sulfolane, etc., and the reaction temperature is -10°C to 60°C. The bromination agent for the bromination reaction is HBr acid, the solvent is dichloromethane, and the reaction temperature is 30°C to 160°C. The reducing agent of the bromide reduction reaction is magnesium powder, etc., the solvent is fatty alcohol, water, chloride, etc., and the reaction temperature is -10°C to 50°C. The invention has the advantages of simple process, low production cost, high product yield and purity, and is suitable for industrialized production.

Description

technical field [0001] The present invention relates to a new preparation method of 2,3,5,6-tetrafluoro-p-methylbenzyl alcohol. It belongs to the preparation technology of 2,3,5,6-tetrafluoro-p-methylbenzyl alcohol. Background technique [0002] 2,3,5,6-Tetrafluoro-p-methylbenzyl alcohol is an important pesticide intermediate used in the preparation of pyrethroid pesticides and the like. The synthetic route of bibliographical report is that 2,3,5,6-tetrafluorobenzene is the synthetic method of raw material through methylation, carbonylation, reduction, and concrete route is as follows: [0003] [0004] The used raw material 2 of this route, 3,5, the reagent used in 6-tetrafluorobenzene and synthetic such as methyl iodide, lithium aluminum hydride are expensive, are not suitable for industrialized production; It needs to be operated at a low temperature of -45°C, and high pressure is required for carbonylation, so that the total yield of 2,3,...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C29/149C07C33/46
Inventor 冯亚青张宝姚光源
Owner TIANJIN UNIV
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