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Preparation method of 1-methylbenzotriazole

A technology for methylbenzotriazole and benzotriazole, which is applied in the field of preparation of 1-methylbenzotriazole, can solve the problems of less separation amount, high separation cost, complicated operation process and the like, and achieves the The effect of low cost, high yield and simple process

Inactive Publication Date: 2013-03-20
ZHEJIANG NORMAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although column chromatography separation can obtain pure 1-methylbenzotriazole and 2-methylbenzotriazole, the operation process is complicated, the separation amount is small, and a large amount of organic solvent and silica gel are needed, and the separation cost High, environmental pollution is big, is not suitable for industrialized production; Recrystallization separation can obtain pure 1-methylbenzotriazole, and operation process is simple, but can not obtain pure 2-methylbenzotriazole, and 1 -The yield of tolyltriazole is low, also not suitable for industrialized production

Method used

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  • Preparation method of 1-methylbenzotriazole

Examples

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Comparison scheme
Effect test

Embodiment 1

[0017] Example 1: Add 119g (1mol) benzotriazole and 275g N,N-dimethylformamide into a 1000mL three-neck round bottom flask, stir at room temperature, and add 44.0 g (1.1mol) sodium hydroxide, stirred at room temperature until the benzotriazole was converted into benzotriazole salt (followed by thin-layer chromatography). Raise the temperature to 90°C, add 144g (1.6mol) dimethyl carbonate dropwise under stirring, and react at a constant temperature until the benzotriazole salt completely participates in the reaction (tracking by thin-layer chromatography). Cool at room temperature, change the reflux device to a vacuum distillation device, collect fractions at 58-68°C (50KPa), recover 256g of N,N-methylformamide, and the recovery rate is 93%. Add 275g of water to dissolve the salt formed in the reaction process to the underpressure distillation residue, let it stand for layers, separate the organic phase, dry it with anhydrous sodium sulfate, filter, and in the filtrate, 1-methy...

Embodiment 2

[0018] Example 2: Add 119g (1mol) benzotriazole and 300g N,N-dimethylformamide into a 1000mL three-neck round bottom flask, stir at room temperature until benzotriazole is completely dissolved, then add in batches 112.0 g (1 mol) of potassium tert-butoxide was reacted until benzotriazole was converted into benzotriazole salt (followed by TLC). Raise the temperature to 100°C, add 117.0 g (1.3 mol) of dimethyl carbonate dropwise under stirring, and react at a constant temperature until the benzotriazole salt completely participates in the reaction (tracked by thin-layer chromatography). Cool at room temperature, change the reflux device to a vacuum distillation device, collect fractions at 58-68°C (50KPa), recover 273g of N,N-dimethylformamide, and the recovery rate is 91%. Add 295g of water to dissolve the salt formed in the reaction process to the underpressure distillation residue, let it stand for layers, separate the organic phase, dry it with anhydrous sodium sulfate, filt...

Embodiment 3

[0019] Example 3: Add 119g (1mol) benzotriazole and 300g N,N-dimethylformamide into a 1000mL three-neck round bottom flask, stir at room temperature until benzotriazole is completely dissolved, then add in batches 123.2 g (1.1 mol) of potassium tert-butoxide was stirred until the benzotriazole was converted to the benzotriazole salt (followed by TLC). Raise the temperature to 95°C, add 157.5 g (1.75 mol) dimethyl carbonate dropwise under stirring, and react at a constant temperature until the benzotriazole salt completely participates in the reaction (tracked by thin-layer chromatography). After cooling at room temperature, change the reflux device to a vacuum distillation device, collect fractions at 58-68°C (50KPa), and recover 276g of N,N-dimethylformamide, with a recovery rate of 92%. Add 300g of water to dissolve the salt formed in the reaction process to the underpressure distillation residue, let it stand for layers, separate the organic phase, dry it with anhydrous sod...

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Abstract

The invention relates to a preparation method of 1-methylbenzotriazole, which comprises the following steps: by using N,N-dimethylformamide as a reaction solvent, reacting benzotriazole with alkali to form a benzotriazole salt; reacting the benzotriazole salt with dimethyl carbonate to obtain a 1-methylbenzotriazole / 2-methylbenzotriazole mixture; and carrying out vacuum distillation to separate 1-methylbenzotriazole from 2-methylbenzotriazole, thereby finally obtaining the 1-methylbenzotriazole. The method is simple to operate, has the advantages of low production cost and small environmental pollution, and is suitable for industrial production.

Description

Technical field: [0001] The invention relates to the field of organic chemistry, in particular to a preparation method of 1-methylbenzotriazole. Background technique: [0002] 1-Methylbenzotriazole is widely used in the fields of cleaning agents for metal surfaces, metal corrosion inhibitors, anti-discoloration agents for metals and their alloys, and is also an important intermediate for the preparation of other benzotriazole derivatives. The existing technology of synthesizing 1-methylbenzotriazole mainly uses dimethyl sulfate [J.Iran.Chem.Soc., 2007, 4 (3), 271-278; J.Mater.Chem., 2003, 13,2451–2456] or iodomethane [Recl.Trv.Chim.Pays-Bas,1991,110(9),369-373; J.Chem.Res.,2004,5,344-346] as a methylation reagent, However, dimethyl sulfate is a highly toxic compound, while methyl iodide is an expensive dangerous product, both of which are unfavorable for industrialized production. Sheng-Yin Zhao et al [Synthetic Communications, 2012, 42:128–135] reported a method for the s...

Claims

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Application Information

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IPC IPC(8): C07D249/18
Inventor 莫海蓝肖孝辉
Owner ZHEJIANG NORMAL UNIVERSITY
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