Process for preparing 2,3,5,6-Tetrafluoro-para-xylyl alcohol

A technology of methyl benzyl alcohol and tetrachloroterephthaloyl chloride, which is applied in a new preparation field, can solve the problems of relatively harsh reaction conditions, unsuitability for industrial production, and high price of lithium aluminum hydride, and achieve convenient source of raw materials, Low production cost, easy and reliable process operation

Inactive Publication Date: 2003-11-26
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] 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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Examples

Experimental program
Comparison scheme
Effect test

example 2

[0021] Preparation of 2,3,5,6-tetrafluoro-tere-phenylene benzyl alcohol

[0022] 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.

[0023] 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

example 3

[0024] Preparation of 2,3,5,6-tetrafluoro-p-bromomethyl benzyl alcohol

[0025] 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.

[0026] 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. Example 4

example 4

[0027] Preparation of 2,3,5,6-tetrafluoro-p-methylbenzyl alcohol

[0028] Dissolve 1.4 g of 2,3,5,6-tetrafluoro-p-bromomethyl benzyl alcohol obtained in Example 3 in 40 mL of methanol, cool in an external ice bath, add 2.8 g of magnesium powder (51.3 mmol) and stir for 2 h, then stir at room temperature 14h. Pour it into 20mL of water, add hydrochloric acid to acidify, then extract with ether, and distill off the ether to obtain 0.7g of a yellow solid product with a yield of 70%. The purity of liquid phase analysis is 97%.

[0029] MS: m / e (relative abundance, %), 194 (M, 97), 173 (M-F-2H, 100), 163 (M-CH 2 OH, 25), 145 (M-F-CH 2 OH+H, 80). Example 5

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Abstract

The preparation process of 2, 3, 5, 6-tetrafluoro-para-xylyl alcohol with 2, 3, 5, 6-tetrachloro-p-phenyl diformyl chloride as material includes fluorination with potassium fluoride, etc. as fluorination agent, sulfolane, etc. as solvent and calixarene, etc. as catalyst and at 40-230 deg.c; esterification of ester with fatty alcohol or aromatic alcohol as esterifying agent and at 20-120 deg.c; reduction of ester with sodium borohydride, etc. as reductant and sulfolane, etc. as solvent, and at -10 deg.c to 60 deg.c; bromination with HBr acid as brominating agent and dichloromethane as solvent and at 30-160 deg.c; and reduction of bromide with magnesium powder, etc as reductant and fatty alcohol, water, chloride, etc as solvent, and at -10 deg.c to 50 deg.c. The present invention has the advantages of simple process, low production cost, high product yield and purity, and is suitable for industrial 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] 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-tetra...

Claims

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Application Information

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