Method for preparing halogen substituted dibenzyl alcohol, its product and application

A technology for dibenzyl alcohol and benzyl alcohol is applied in the preparation of halogen-substituted dibenzyl alcohol, the thus prepared halogen-substituted dibenzyl alcohol and the field of use thereof, which can solve the problem of affecting the purity and yield and the yield of dibenzyl compound and poor purity, etc., to achieve the effect of high yield

Inactive Publication Date: 2002-11-20
SALTIGO GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Another fatal flaw is the relatively poor yield and purity of the dibenzyl compounds obtained in all the other methods for the preparation of both monobenzyl alcohol and dibenzyl alcohol
Concluding from these facts, it is clear that the functionality of the desired product dibenzyl compound and the asymmetric intermediates formed during the synthesis greatly affect the purity and yield

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment Embodiment 1

[0038] EXAMPLES Example 1: Acid hydrolysis of 2,3,5,6-tetrafluoroterephthalic acid

[0039] First, 7320g of 98% concentrated sulfuric acid was added together with 30g of sodium silicate and 30g of silicone oil and heated at 100°C, and tetrafluoroterephthalonitrile was added in 6 parts, each part being 254.6g. The mixture was then heated to 170°C and stirred at this temperature for 1 hour. At 170° C., 2440 g of water were metered in within 3 hours, the mixture was then allowed to cool to 20° C., and the precipitated solid was removed by filtration. The residue was washed twice with water, each time with 500 g of water, and then dried to obtain 1769.0 g of tetrafluoroterephthalic acid, with a content of 96% (the remainder being 100% silicate inorganic components), (yield 99.5%) . Example 2: Hydroboration reduction of 2,3,5,6-tetrafluoroterephthalic acid with dimethyl sulfate to obtain 2,3,5,6-tetrafluorodibenzyl alcohol

Embodiment 2

[0039] First, 7320g of 98% concentrated sulfuric acid was added together with 30g of sodium silicate and 30g of silicone oil and heated at 100°C, and tetrafluoroterephthalonitrile was added in 6 parts, each part being 254.6g. The mixture was then heated to 170°C and stirred at this temperature for 1 hour. At 170° C., 2440 g of water were metered in within 3 hours, the mixture was then allowed to cool to 20° C., and the precipitated solid was removed by filtration. The residue was washed twice with water, each time with 500 g of water, and then dried to obtain 1769.0 g of tetrafluoroterephthalic acid, with a content of 96% (the remainder being 100% silicate inorganic components), (yield 99.5%) . Example 2: Hydroboration reduction of 2,3,5,6-tetrafluoroterephthalic acid with dimethyl sulfate to obtain 2,3,5,6-tetrafluorodibenzyl alcohol

[0040] In a 16-liter glass reactor, 534.5 g of sodium borohydride and 3000 g of 1,2-dimethoxyethane were first added. At 60° C., the conten...

Embodiment 3

[0042] The mixture was cooled to 65°C, then 4500 g of water was added over 2 hours, the mixture was heated and stirred at 90°C for 10 hours, then cooled to 60°C, 1500 g of ethyl acetate was added, and the mixture was stirred for 0.5 hours. The phases were separated and the aqueous phase was extracted twice with 5000 g of ethyl acetate each time. The organic phases are combined and concentrated to 12 liters, if necessary replacing the ethyl acetate with 3000 g of toluene by distillation. At 80°C, the mixture was washed with 500 g of saturated sodium carbonate solution and then cooled to 20°C. The precipitated solvent was separated by filtration and, if necessary, washed with 1000 g of toluene to remove adhering mother liquor. The product was dried to yield 1123.5 g (90.5%) of a colorless solid with a purity of 98.7%. Example 3: Reduction of 2,3,5,6-tetrafluoroterephthalic acid with sulfuric acid hydroboration to obtain 2,3,5,6-tetrafluorodibenzyl alcohol

[0043] In a 16-lit...

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PUM

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Abstract

A novel and simple method for the preparation of high-purity halogen-substituted dibenzyl alcohols by reducing the corresponding halogen-substituted terephthalic acid and reacting with alkylating reagents, sulfuric acid, alkyl or arylsulfonic acids. The obtained high-purity halogen-substituted dibenzyl alcohol is particularly suitable for preparing compounds with pharmaceutical and agrochemical activities.

Description

technical field [0001] The present invention relates to a method for preparing halogen-substituted dibenzyl alcohol from corresponding halogen-substituted terephthalic acid, and the halogen-substituted dibenzyl alcohol obtained from the method and its use in the preparation of pharmaceutically active and agrochemically active compounds the use of. Background technique [0002] 2,3,5,6-Tetrahalogenated dibenzyl alcohols are known to those skilled in the art as important intermediates, for example for the preparation of pharmaceutically or agrochemically active compounds, such as insecticides . In particular, 2,3,5,6-tetrafluorodibenzyl alcohol is an important intermediate for the preparation of insecticidally active pyrethroids. [0003] The use of 2,3,5,6-tetrafluorodibenzyl alcohol as starting material for the preparation of household insecticides is described, for example, in EP-A-0963976, EP-A-0959065, EP-A-0302612 and EP-A-0302612 -A-0926129. [0004] GB-A-2127013 de...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C29/147C07C33/46
CPCA61P33/00C07C29/147C07C33/46
Inventor L·罗德菲尔德
Owner SALTIGO GMBH
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