Method for preparing 2-cyanophenol

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 by using salicylaldehyde and hydroxylamine hydrochloride as raw materials. Background technique

[0002] O-Hydroxybenzonitrile is an important intermediate for pesticides, fragrances, liquid crystal materials, etc., especially the key intermediate for the synthesis of methoxy acrylate fungicide azoxystrobin. It is widely used in agrochemicals, pharmaceutical chemicals and other industries Applications. There are well-known techniques for the preparation of o-hydroxybenzonitrile, and there are mainly two synthetic routes, respectively, which use salicylamide and salicylaldehyde as raw materials to synthesize o-hydroxybenzonitrile. Among them, the preparation of o-hydroxybenzonitrile by dehydration with salicylamide as a raw material is a promising process. There have been a large number of reports in the litera...

Examples

Embodiment 1

[0033] The first step (preparation of salicylaldoxime): Add 18% by weight of sodium bicarbonate to the hydroxylamine hydrochloride aqueous solution with a concentration of 27% by weight in batches, and stir while adding. After the solution is clarified 58% of methanol and 38% of salicylaldehyde in the total hydroxylamine hydrochloride aqueous solution were added in weight percentages, and reacted at a temperature of 87.5±2.5° C. for 1 hour, the organic phase was evaporated, and white crystals were obtained after solvent removal.

[0034] The second step (dehydration): add 110% by weight of acetic anhydride in the total hydroxylamine hydrochloride aqueous solution to the white crystals, react at a temperature of 127.5±2.5°C for 2.5 hours, and remove the solvent to obtain a dark brown liquid.

[0035] The third step (hydrolysis and acidification): add 42% potassium hydroxide solution of the total amount of the hydroxylamine hydrochloride aqueous solution to the dark brown liquid. In t...

Embodiment 2

[0037] The first step (preparation of salicylaldoxime): Add 35% by weight of sodium carbonate to the hydroxylamine hydrochloride aqueous solution with a concentration of 23% by weight in batches, and stir while adding. After the solution is clarified, respectively Add 56% ethanol and 38% salicylaldehyde in the total weight of hydroxylamine hydrochloride aqueous solution, react at 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 Crystal, filter and dry.

[0038] The second step (dehydration): add 120% by weight of acetic anhydride in the total amount of hydroxylamine hydrochloride aqueous solution to the above-mentioned dried white crystals, and react at a temperature of 127.5±2.5°C for 3 hours, and the solvent will be removed to obtain a dark brown liquid.

[0039] The third step (hydrolysis and acidification): add 40% potassium hydroxide solution of the total amount of the hydroxylamine hydroc...

Embodiment 3～10

[0041] Examples 3-10: Preparation of o-hydroxybenzonitrile according to the substance type, concentration, dosage and process parameters in the following table, and other implementation conditions are the same as in Example 2.

[0042] real

[0043] real

[0044] real

Technical field

[0001] The invention relates to a preparation method of o-hydroxybenzonitrile, in particular to a preparation method for synthesizing o-hydroxybenzonitrile by using salicylaldehyde and hydroxylamine hydrochloride as raw materials. Background technique

[0002] O-Hydroxybenzonitrile is an important intermediate for pesticides, fragrances, liquid crystal materials, etc., especially the key intermediate for the synthesis of methoxy acrylate fungicide azoxystrobin. It is widely used in agrochemicals, pharmaceutical chemicals and other industries Applications. There are well-known techniques for the preparation of o-hydroxybenzonitrile, and there are mainly two synthetic routes, respectively, which use salicylamide and salicylaldehyde as raw materials to synthesize o-hydroxybenzonitrile. Among them, the preparation of o-hydroxybenzonitrile by dehydration with salicylamide as a raw material is a promising process. There have been a large number of reports in the litera...

Examples

Embodiment 1

[0033] The first step (preparation of salicylaldoxime): Add 18% by weight of sodium bicarbonate to the hydroxylamine hydrochloride aqueous solution with a concentration of 27% by weight in batches, and stir while adding. After the solution is clarified 58% of methanol and 38% of salicylaldehyde in the total hydroxylamine hydrochloride aqueous solution were added in weight percentages, and reacted at a temperature of 87.5±2.5° C. for 1 hour, the organic phase was evaporated, and white crystals were obtained after solvent removal.

[0034] The second step (dehydration): add 110% by weight of acetic anhydride in the total hydroxylamine hydrochloride aqueous solution to the white crystals, react at a temperature of 127.5±2.5°C for 2.5 hours, and remove the solvent to obtain a dark brown liquid.

[0035] The third step (hydrolysis and acidification): add 42% potassium hydroxide solution of the total amount of the hydroxylamine hydrochloride aqueous solution to the dark brown liquid. In t...

Embodiment 2

[0037] The first step (preparation of salicylaldoxime): Add 35% by weight of sodium carbonate to the hydroxylamine hydrochloride aqueous solution with a concentration of 23% by weight in batches, and stir while adding. After the solution is clarified, respectively Add 56% ethanol and 38% salicylaldehyde in the total weight of hydroxylamine hydrochloride aqueous solution, react at 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 Crystal, filter and dry.

[0038] The second step (dehydration): add 120% by weight of acetic anhydride in the total amount of hydroxylamine hydrochloride aqueous solution to the above-mentioned dried white crystals, and react at a temperature of 127.5±2.5°C for 3 hours, and the solvent will be removed to obtain a dark brown liquid.

[0039] The third step (hydrolysis and acidification): add 40% potassium hydroxide solution of the total amount of the hydroxylamine hydroc...

Embodiment 3～10

[0041] Examples 3-10: Preparation of o-hydroxybenzonitrile according to the substance type, concentration, dosage and process parameters in the following table, and other implementation conditions are the same as in Example 2.

[0042] real

[0043] real

[0044] real