Method for producing 2-chloro-3-cyanopyridine through continuous reaction

A technology for cyanopyridine and cyanopyridine nitrogen oxide, which is applied in the production field of 2-chloro-3-cyanopyridine, can solve the problems of unsolvable production efficiency, low reaction condition control and the like

Active Publication Date: 2015-08-12
JIANGSU ZHONGZHENG BIOCHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although this reaction method has high selectivity and few by-products, it still cannot solve technical problems such as low production efficiency and difficult control of reaction conditions.

Method used

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  • Method for producing 2-chloro-3-cyanopyridine through continuous reaction
  • Method for producing 2-chloro-3-cyanopyridine through continuous reaction

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] The weight ratio of 3-cyanopyridine nitrogen oxide, phosphorus oxychloride and triethylamine is 1:5:0.8, and the ratio of 1:5:0.8 is continuously added to the No. 1 reactor, and the temperature in the reactor is maintained at 20°C by controlling the feed rate. ~25°C; the reaction solution enters the No. 2 and No. 3 reactors from the No. 1 reactor in turn, and the temperature of the No. 2 kettle is controlled at 40~50°C, and the temperature of the No. 3 kettle is controlled at 80~90°C. The average residence time of the reaction solution in the No. 3 kettle The time is controlled within 1 to 2 hours, and the reaction liquid in the No. 3 kettle continuously enters the subsequent distillation recovery system.

[0015] The above reaction solution is distilled under reduced pressure to recover phosphorus oxychloride, the vacuum at the end of recovery is -0.06~-0.09MPa, the temperature is 85~105°C, and there is no obvious distillation of phosphorus oxychloride.

[0016] The co...

Embodiment 2

[0018] The weight ratio of 3-cyanopyridine nitrogen oxide, phosphorus oxychloride and triethylamine is 1:5:0.8, and the ratio of 1:5:0.8 is continuously added to the No. 1 reactor, and the temperature in the reactor is maintained at 20°C by controlling the feed rate. ~25°C; the reaction liquid enters the No. 2 reactor from the No. 1 reactor, and the temperature of the No. 2 pot is controlled at 80~90°C. The liquid continuously enters the subsequent distillation recovery system.

[0019] The above reaction solution is distilled under reduced pressure to recover phosphorus oxychloride, the vacuum at the end of recovery is -0.06~-0.09MPa, the temperature is 85~105°C, and there is no obvious distillation of phosphorus oxychloride.

[0020] The concentrated solution after recovery of phosphorus oxychloride is slowly put into 10 times of water to precipitate 2-chloro-3-cyanopyridine, control the discharge temperature not higher than 50°C, cool down to below 40°C after discharge and ...

Embodiment 3

[0022] 3-cyanopyridine nitrogen oxide and phosphorus oxychloride are continuously added to No. 1 reactor at a ratio of 1:5 by weight; the reaction solution overflows from No. 1 reactor and enters No. The weight ratio of pyridine nitrogen oxide and triethylamine is 1:0.8, and triethylamine is continuously added to No. 2 reactor, and the reaction temperature is controlled at 20 ° C ~ 25 ° C; the reaction liquid enters No. 3 reaction tank from No. 2 reactor The temperature of the No. 3 kettle is controlled at 80-90°C. The average residence time of the reaction solution in the No. 3 kettle is controlled at 1-2 hours. The reaction solution in the No. 3 kettle continuously enters the subsequent distillation recovery system.

[0023] The above reaction solution is distilled under reduced pressure to recover phosphorus oxychloride, the vacuum at the end of recovery is -0.06~-0.09MPa, the temperature is 85~105°C, and there is no obvious distillation of phosphorus oxychloride.

[0024] ...

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Abstract

The invention belongs to the field of organic synthesis, and particularly relates to a method for producing 2-chloro-3-cyanopyridine. The method is implemented by taking nicotinonitrile-1-oxide, phosphorus oxychloride and triethylamine as raw materials through the steps that the three raw materials are simultaneously continuously dropwise added into a first reactor, and the reaction temperature is controlled at minus 10-40 DEG C; and a reaction liquid in the first reactor continuously enters subsequent reactors connected in series to react at a reaction temperature of 80-100 DEG C, 1-2 hours later, the reaction liquid is distilled for recovering phosphorus oxychloride, and the phosphorus oxychloride is subjected to hydraulic analysis, so that 2-chloro-3-cyanopyridine is obtained. The method is implemented by adopting a continuous reaction thought, and reaction conditions in the related reactors are smooth, so that the implementation of automation control is facilitated, therefore, the method has the advantages of safe process, high production efficiency, stable product quality, and the like.

Description

technical field [0001] The invention belongs to the field of organic synthesis, in particular to a production method of 2-chloro-3-cyanopyridine. Background technique [0002] 2-Chloronicotinic acid is an important pesticide and pharmaceutical intermediate, used in the preparation of anti-AIDS drug nevirapine, new herbicides nicosulfuron, diflufenamide, etc. 2-Chloro-3-cyanopyridine is an important intermediate in the synthesis of 2-chloronicotinic acid, which can be hydrolyzed and acidified to obtain 2-chloronicotinic acid. The traditional production method of 2-chloro-3-cyanopyridine adopts kettle-type batch reaction, and drops phosphorus oxychloride and 3-cyanopyridine nitrogen oxide (or nicotinamide nitrogen oxide, nicotinic acid nitrogen oxide) in the reactor and its mixture), add the acid-binding agent triethylamine dropwise between 5~40°C; after the addition of triethylamine, slowly raise the temperature to 80~100°C and keep it warm for 2~3 hours. The heating process...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/85
CPCC07D213/85
Inventor 邱水发谢秋平冯奇胡兵
Owner JIANGSU ZHONGZHENG BIOCHEM CO LTD
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