Synthesis method of benzotriazole

Abstract

The invention discloses a synthesis method of benzotriazole. The synthesis method comprises the following steps: adding o-nitrochlorobenzene and hydrazine hydrate into tetrahydrofuran serving as a solvent to synthesize 1-hydroxybenzotriazole, and reducing the 1-hydroxybenzotriazole to prepare the benzotriazole. The benzotriazole preparation principle of the synthesis method provided by the invention is the same as the preparation principle of the existing method. The yield of the benzotriazole is improved by changing reaction temperature, reaction time, selection of the solvent, and an extraction method in preparation of the benzotriazole.

Description

technical field

[0001] The invention relates to a method for synthesizing a pharmaceutical intermediate, in particular to a method for synthesizing benzotriazole. Background technique

[0002] Benzotriazole (BTA) is an important fine chemical product. It has a wide range of uses, mainly used as corrosion inhibitors for copper and copper alloys, photographic antifogging agents, metal antirust agents and organic synthesis intermediates; it is also widely used in paint additives, lubricating oil additives, synthetic dye intermediates, synthetic washing Preservatives, anticoagulants, polymer material stabilizers, plant growth regulators, anti-tarnish agents, gas phase corrosion inhibitors, UV absorbers, and analytical reagents.

[0003] Many researchers at home and abroad have done a lot of research work on the synthesis of BTA. So far, the reported synthetic routes include o-phenylenediamine method, benzimidazolone method, o-nitrophenylhydrazine method, and o-nitrochlorobenze...

Examples

Embodiment 1

[0021] The synthetic method of benzotriazole of the present invention comprises the following steps:

[0022] S1. In the reaction kettle, using tetrahydrofuran as a solvent, add a certain amount of o-nitrochlorobenzene, 85% hydrazine hydrate with a molar ratio of 3.5 times of o-chloronitrobenzene, heat up to 80-110°C, reflux for 3-5h, and then add 20% NaOH solution, the amount of substance in the 20% NaOH solution is twice the amount of substance in o-nitrochlorobenzene;

[0023] S2, the reaction solution after the reaction in step S1 uses alcohol-water-hydrazine azeotropic distillation to recover hydrazine hydrate, and adopts the mode of raising temperature to recover dimethyl sulfoxide;

[0024] S3. Add a certain amount of water to the residual liquid after recovering hydrazine hydrate and dimethyl sulfoxide in step S2 until the residue is completely dissolved and then add concentrated hydrochloric acid. At this time, a large amount of white crystals are precipitated. Filter...

technical field

[0001] The invention relates to a method for synthesizing a pharmaceutical intermediate, in particular to a method for synthesizing benzotriazole. Background technique

[0002] Benzotriazole (BTA) is an important fine chemical product. It has a wide range of uses, mainly used as corrosion inhibitors for copper and copper alloys, photographic antifogging agents, metal antirust agents and organic synthesis intermediates; it is also widely used in paint additives, lubricating oil additives, synthetic dye intermediates, synthetic washing Preservatives, anticoagulants, polymer material stabilizers, plant growth regulators, anti-tarnish agents, gas phase corrosion inhibitors, UV absorbers, and analytical reagents.

[0003] Many researchers at home and abroad have done a lot of research work on the synthesis of BTA. So far, the reported synthetic routes include o-phenylenediamine method, benzimidazolone method, o-nitrophenylhydrazine method, and o-nitrochlorobenze...

Examples

Embodiment 1

[0021] The synthetic method of benzotriazole of the present invention comprises the following steps:

[0022] S1. In the reaction kettle, using tetrahydrofuran as a solvent, add a certain amount of o-nitrochlorobenzene, 85% hydrazine hydrate with a molar ratio of 3.5 times of o-chloronitrobenzene, heat up to 80-110°C, reflux for 3-5h, and then add 20% NaOH solution, the amount of substance in the 20% NaOH solution is twice the amount of substance in o-nitrochlorobenzene;

[0023] S2, the reaction solution after the reaction in step S1 uses alcohol-water-hydrazine azeotropic distillation to recover hydrazine hydrate, and adopts the mode of raising temperature to recover dimethyl sulfoxide;

[0024] S3. Add a certain amount of water to the residual liquid after recovering hydrazine hydrate and dimethyl sulfoxide in step S2 until the residue is completely dissolved and then add concentrated hydrochloric acid. At this time, a large amount of white crystals are precipitated. Filter...