Preparation method of 2-chloro-5-picoline

A technology of methyl pyridine and benzyl chloride, applied in the field of preparation of 2-chloro-5-methyl pyridine, can solve the problems of difficult industrialization, many by-products, complicated operation, etc., and achieves reduction of production processing steps and improved reaction Selectivity, the effect of reducing environmental pollution

Inactive Publication Date: 2016-02-17
SHANGHAI JINJING CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] 1. Using morpholine and propionaldehyde as raw materials, they are synthesized through cyclization, dehydrogenation, chlorination and other reactions. This method has a long route, complicated operation, serious environmental pollution and high overall cost; (US4612377, US4645839);
[0005] 2. Using 3-picoline as a raw material, it is synthesized through nitrogen oxidation, chlorination and other reactions. This type of method has easy-to-obtain raw materials, fewer reaction steps, and lower cost, but this type of method has poor route selectivity, many by-products, and product separation Purification is difficult, it is difficult to obtain high-purity products or the purification cost is high and the yield is low; (EP0393453, EP0512436);
[0006] 3. Using nicotinic acid as a raw material, it is synthesized through reac

Method used

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  • Preparation method of 2-chloro-5-picoline

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Effect test

Embodiment 1

[0034] The preparation of compound b benzylamine

[0035] In a 10000L stainless steel reaction kettle, put 2000kg of water and pass through ammonia gas, the detection concentration reaches 25-30%, add or recover 2000kg of benzyl chloride and 1800kg of benzaldehyde, heat up to 60°C in a closed system, and control the pressure at 2 atm, keep warm for 6-8 hours, HLC traces benzyl chloride ≤ 0.1%, that is, the reaction is complete. After the reaction, the solution cools down to 20-25°C and stratifies. Put it into another 10000L reaction kettle, use 1600kg of 30% hydrochloric acid, adjust PH=1, raise the temperature to 60°C, and separate layers at rest. The oil layer is benzaldehyde, which can be applied mechanically, and the water layer is benzylamine hydrochloride. 1600kg of 40% liquid caustic soda, adjusted to PH=10, static layering, to obtain crude benzylamine, which was then collected by vacuum distillation at 90-102°C / 10mmHg to obtain 1573.3kg of compound benzylamine, GC≥99.2...

Embodiment 2

[0043] The preparation of compound b benzylamine

[0044] In a 10000L stainless steel reaction kettle, put 2000kg of water and pass through ammonia gas, and the detection concentration will reach 25-30%. 1.5 atm, keep warm for 6-8 hours, HLC traces benzyl chloride ≤ 0.1%, that is, the reaction is complete, after the reaction, the solution cools down to 20-25°C and stratifies, and 635kg of caustic soda is added to the water layer, and the next batch of ammonia gas is put into the oil layer. Transfer to another 10000L reaction kettle, use 1600kg of 30% hydrochloric acid, adjust PH=1, heat up to 55°C, and separate into layers, the oil layer is benzaldehyde, and the water layer is benzylamine hydrochloride. At 30°C, Add 1600kg of 40% liquid caustic soda, adjust the pH to 10-11, and separate layers at rest to obtain crude benzylamine. The crude benzylamine is then collected by vacuum distillation at 90-102°C / 10mmHg to obtain 1573.3kg of compound benzylamine, GC≥99.2%, molar yield ...

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Abstract

The invention relates to a preparation method of 2-chloro-5-picoline. According to the method, benzyl chloride is taken as a raw material, benzaldehyde is taken as an inhibitor, ammonia is taken as an aminating agent, a product has a condensation reaction with propionaldehyde under the catalysis of an organic base, then a product has acetylation with an acetylation reagent, finally, a product performs cyclization under actions of N,N-dimethylformamide and triphosgene, and the target product 2-chloro-5-picoline is obtained through purification. The product purity is higher than or equal to 99.5%, and the total molar yield higher than 80% is realized. The preparation method of 2-chloro-5-picoline has good reaction selectivity, high yield and few three wastes, is simple to operate and facilitates industrialized production.

Description

technical field [0001] The invention belongs to the technical field of fine chemical preparation, and in particular relates to a preparation method of 2-chloro-5-picoline. Background technique [0002] 2-Chloro-5-picoline is an important pesticide intermediate, which can be used to synthesize imidacloprid, acetamiprid, nitenpyram and other neonicotinoid insecticides. Spectrum high efficiency, low toxicity, less dosage, long duration, good safety, strong drug resistance and other advantages, these products have a huge production tonnage, therefore, the development of high yield, high quality, high safety, low environmental protection, low cost 2 -Chloro-5-picoline has practical significance. [0003] At present, there are mainly five methods for the synthesis of 2-chloro-5-picoline: [0004] 1. Using morpholine and propionaldehyde as raw materials, they are synthesized through cyclization, dehydrogenation, chlorination and other reactions. This method has a long route, comp...

Claims

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Application Information

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IPC IPC(8): C07D213/61
CPCC07D213/61
Inventor 龙聪未周仙配马俊唐松青吕叶军
Owner SHANGHAI JINJING CHEM CO LTD
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