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Method for preparing 2-cyanophenol

A technology for o-hydroxybenzonitrile and hydroxylamine salt is applied in the preparation field of synthesizing o-hydroxybenzonitrile, can solve the problems of restricting industrial production, expensive dehydrating agent, easy deterioration of salicylaldehyde, etc., and achieves low equipment cost, good properties, The effect of improving product purity

Inactive Publication Date: 2013-03-27
CHONGQING UNISPLENDOUR CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Wherein taking salicylamide as raw material to prepare o-hydroxybenzonitrile through dehydration is a promising process route, which has been reported in a large number of documents, but under the premise of achieving a better dehydration effect, the dehydrating agent used is either expensive, Or the problem of safety and environmental protection is serious, therefore, the selection of dehydrating agent has restricted the industrialized production of this method
CN94191224.8 describes the reaction between salicylaldehyde and hydroxylamine, and then dehydrates the generated salicylaldoxime to prepare o-hydroxybenzonitrile. This method needs to prepare metal salts or complexes of salicylaldehyde in advance, and the process flow is long and the operation is cumbersome. , and the amount of organic wastewater is large
The method for preparing salicylaldoxime from salicylaldehyde was reported earlier by Welcher F J (New York: DVan Nostrand Co., 259, 1947) and Windholz Marthz (Rahway (New Jesey): Merk & Co., Inc., 8296, 1988) A method for preparing salicylaldoxime from salicylaldehyde, sodium hydroxide solution, and hydroxylamine hydrochloride. This reaction is carried out under alkaline conditions, which is unfavorable for the condensation reaction of salicylaldehyde and hydroxylamine; and salicylaldehyde is easily deteriorated when heated under alkaline conditions. , will reduce product quality. In addition, the post-treatment of this method requires crystallization and recrystallization of benzene and a mixed solution of benzene and petroleum ether. The use of highly toxic solvent benzene is its fatal shortcoming; moreover, the method is cumbersome to operate and the yield is low High, and the product is slightly red, affecting subsequent use

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] The first step (preparation of salicylaldoxime): in the hydroxylamine hydrochloride aqueous solution of 27% concentration by weight, add in batches the sodium bicarbonate that accounts for 18% of the hydroxylamine hydrochloride aqueous solution total amount by weight percent, stir while adding, after the solution is clarified Add 58% of methanol and 38% of salicylaldehyde to the total amount of hydroxylamine hydrochloride aqueous solution in percentage by weight, react at a temperature of 87.5±2.5° C. for 1 hour, evaporate the organic phase, and obtain white crystals after desolventization.

[0034] Second step (dehydration): add the acetic anhydride that accounts for 110% of hydroxylamine hydrochloride aqueous solution total amount by weight percentage in above-mentioned white crystal, react 2.5 hours at the temperature of 127.5 ± 2.5 ℃, desolventize and obtain dark brown liquid.

[0035]The 3rd step (hydrolytic acidification): in the above-mentioned dark brown liquid, ...

Embodiment 2

[0037] The first step (preparation of salicylaldoxime): in the hydroxylamine hydrochloride aqueous solution of 23% concentration by weight, add in batches the sodium carbonate that accounts for 35% of the hydroxylamine hydrochloride aqueous solution total amount by weight percent, stir while adding, after solution clarification, respectively Add 56% ethanol and 38% salicylaldehyde which account for the total amount of hydroxylamine hydrochloride aqueous solution in terms of weight percentage, react at a temperature of 87.5±2.5°C for 0.8 hours, separate the organic phase, wash with water, add appropriate amount of industrial water, and precipitate white Crystals, filtered and dried.

[0038] The second step (dehydration): add the acetic anhydride that accounts for 120% of the total amount of the hydroxylamine hydrochloride aqueous solution in weight percent to the above-mentioned completely dry white crystal, and react at a temperature of 127.5±2.5° C. for 3 hours, and the solve...

Embodiment 3～10

[0041] Embodiments 3-10: o-Hydroxybenzonitrile was prepared according to the substance type, concentration, dosage and process parameters in the following table, and other implementation conditions were the same as in Embodiment 2.

[0042] Reality

[0043]

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Abstract

The invention discloses a method for preparing 2-cyanophenol, which comprises the following steps: preparing salicylaldoxime; performing dehydration; and performing hydrolytic-acidification reaction, wherein in the dehydration, anhydride is adopted as a dehydrating agent; and in the hydrolytic-acidification reaction, a hydrolyticreagent is 10 to 30 mass percent alkaline solution, and the temperature of the hydrolytic-acidification reaction is 100 to 150DEG C. The preparation method comprises three steps of preparing the salicylaldoxime; performing dehydration; and performing hydrolytic-acidification reaction; the operation in each step is easy and feasible; the product generated in the third step is not needed to be recrystallized, the purity can reach over 95 percent and the total yield can reach over 92 percent; the process flow is simple, the product is easily produced industrially and the equipment cost is low; besides, the raw materials and auxiliary materials used in the invention are conventional chemical reagents, the varieties are single, and partial solvents can be recycled, so the problems of large wastewater quantity, high price of the dehydrating agent, potential safety hazard, high recrystallization cost and the like in the prior art are solved.

Description

technical field [0001] The invention relates to a preparation method of o-hydroxybenzonitrile, in particular to a preparation method for synthesizing o-hydroxybenzonitrile with salicylaldehyde and hydroxylamine hydrochloride as raw materials. Background technique [0002] O-hydroxybenzonitrile is an important intermediate for pesticides, spices, liquid crystal materials, etc., especially the key intermediate for the synthesis of methoxyacrylate fungicide azoxystrobin, and has been widely used in agricultural chemicals, pharmaceutical chemicals and other industries Applications. There are known techniques for the preparation of o-hydroxybenzonitrile, and there are mainly two synthetic approaches, respectively using salicylamide and salicylaldehyde as raw materials to synthesize o-hydroxybenzonitrile. Wherein taking salicylamide as raw material to prepare o-hydroxybenzonitrile through dehydration is a promising process route, which has been reported in a large number of docum...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C255/53C07C253/30C07C253/34
Inventor 金海琴屈琦超苗兰冬胡欣姚如杰李春霞
Owner CHONGQING UNISPLENDOUR CHEM
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