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Preparation method for 5-tolytriazole

A technology of tolyltriazole and diaminotoluene, which is applied in the field of preparation of tolyltriazole, can solve the problem that it is difficult to produce high-purity 5-methylbenzotriazole and meet the requirements of high-purity Requirements and other issues to achieve the effect of improving purity

Inactive Publication Date: 2017-04-26
NANTONG BOTAO CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The existing production method is difficult to produce high-purity 5-methylbenzotriazole due to the impurity doped in the raw material during preparation, and generally only 4-methylbenzotriazole and 5-methylbenzotriazole can be produced. The mixture of benzotriazoles, which makes it difficult to meet the high purity requirements

Method used

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Examples

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Effect test

preparation example Construction

[0018] The preparation method of 5-methylbenzotriazole of the present invention, the specific steps of this preparation method are as follows:

[0019] (1) Use the pulse injection method to inject the methanol solution of 2,3-diaminotoluene with a mass percentage concentration of 20% to 30% into the adsorption column filled with molecular sieves through the injection pump. Adsorption separation is carried out under the condition of column flow rate of 1-2mL / min, 2,3-diaminotoluene with a purity of 99.3%-99.4% can be obtained before 60 minutes, and 2,3-diaminotoluene with a purity of 99.7%-99.9% can be obtained after 75 minutes 3,4-diaminotoluene;

[0020] (2) In the reactor, place 3,4-diaminotoluene with a purity of 99.7% to 99.9% in step (1) in 0.6 to 1.2 times the weight of pure water, heat and maintain a temperature of 90 to 100°C , and stir to make it fully dissolved;

[0021] (3) Add 0.6-0.8 times sodium nitrite to the solution formed in step (2), keep the reaction pres...

Embodiment 5

[0029] The preparation method of the present embodiment 5-methylbenzotriazole, the specific steps of the preparation method are as follows:

[0030] (1) Inject a methanol solution of 2,3-diaminotoluene with a concentration of 30% by mass into the adsorption column filled with KY molecular sieves through the injection pump through the pulse injection method. Under the condition of adsorption separation per minute, 2,3-diaminotoluene with a purity of 99.36% can be obtained before 60 minutes, and 3,4-diaminotoluene with a purity of 99.78% can be obtained after 75 minutes;

[0031] (2) In the reactor, place the 3,4-diaminotoluene with a purity of 99.78% in step (1) in 1.2 times the weight of pure water, heat, keep the temperature at 100°C, and stir to make it fully dissolve;

[0032] (3) Add sodium nitrite 0.8 times that of 3,4-diaminotoluene to the solution formed in step (2), keep the reaction pressure at 6MPa, keep the temperature at 280°C, and stir for 3 hours, then cool the ...

Embodiment 2

[0038] The preparation method of the present embodiment 5-methylbenzotriazole, the specific steps of the preparation method are as follows:

[0039] (1) Inject a methanol solution of 2,3-diaminotoluene with a concentration of 30% by mass into the adsorption column filled with BaY molecular sieves through the injection pump through the pulse injection method. Under the condition of adsorption separation per minute, 2,3-diaminotoluene with a purity of 99.3% can be obtained before 60 minutes, and 3,4-diaminotoluene with a purity of 99.72% can be obtained after 75 minutes;

[0040] (2) In the reactor, place the 3,4-diaminotoluene with a purity of 99.72% in step (1) in 1.2 times the weight of pure water, heat, keep the temperature at 100°C, and stir to make it fully dissolve;

[0041] (3) Add sodium nitrite 0.8 times that of 3,4-diaminotoluene to the solution formed in step (2), keep the reaction pressure at 6MPa, keep the temperature at 280°C, and stir for 3 hours, then cool the ...

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Abstract

The invention relates to a preparation method for 5-tolytriazole. The preparation method comprises the following concrete steps: (1) separating 2,3-diaminotoluene and 3,4-diaminotoluene through column chromatography; (2) subjecting 3,4-diaminotoluene obtained in the step (1) and sodium nitrite to a reaction in a reactor; (3) dropwise adding sulfuric acid into the solution obtained in the step (2), and maintaining the pH value to be 5 to 6 so as to generate a large number of crystals; (4) subjecting a mixture of the crystals obtained in the step (3) and a liquid to fluid-loss treatment; (5) heating the crystal obtained in the step (4), and carrying out dehydration; and (6) distilling the crystal obtained in the step (5) so as to prepare the 5-tolytriazole. The invention has the following advantages: 2,3-diaminotoluene and 3,4-diaminotoluene in raw materials are separated through column chromatography, and the purity of the raw materials is improved, so the purity of a product is increased.

Description

technical field [0001] The present invention relates to the preparation method of tolyl benzotriazole, particularly a kind of 5-methyl benzotriazole [0002] The preparation method of benzotriazole. Background technique [0003] Benzotriazole is a rust and corrosion inhibitor for metals, and methyl benzotriazole is mainly used as a rust and inhibitor for metals (such as silver, copper, lead, nickel, zinc, etc.) Corrosion agent, widely used in antirust oil (grease) products, mostly used as gas phase corrosion inhibitor of copper and copper alloy, circulating water treatment agent, automobile antifreeze, polymer stabilizer, plant growth regulator, lubricating oil additive , ultraviolet absorbers, etc., and can also be used in conjunction with a variety of scale inhibitors, bactericides and algaecides, especially for closed-loop cooling water systems with excellent corrosion inhibition effects. [0004] 5-methylbenzotriazole is a high-purity reagent-grade intermediate, mainly...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D249/18
CPCC07D249/18
Inventor 黄海涛王宏李桂萍
Owner NANTONG BOTAO CHEM