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Method for preparing pyridine-2-formic acid by hydrogenation reduction of poly chloro pyridine-2-formic acid mixture

A technology for polychlorinated pyridine and dichloropicolinic acid, which is applied in the field of chemical waste recycling and reuse, can solve the problems of complex composition of polychlorinated pyridine-2-carboxylic acid mixture, increased processing cost, large composition change, etc., and achieves obvious economical benefits. Advantages and environmental advantages, easy operation, low cost effect

Inactive Publication Date: 2016-04-06
ZHEJIANG AVILIVE CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The composition of the polychloropyridine-2-carboxylic acid mixture is complex, generally containing 20-60% of 3,6-dichloropicolinic acid, and other chloropicolinic acids, and the composition changes greatly. Simple physical and chemical methods It is already difficult to purify, and it is generally treated as solid waste directly. However, this not only wastes some products, but also increases the treatment cost. Therefore, it is urgent to provide a more economical and convenient treatment method.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] (1) 50 grams of polychlorinated pyridine-2-formic acid waste mixture, 400 ml of water, and 139.6 grams of 30% sodium hydroxide are mixed uniformly, filtered, and the filtrate is taken, and poured into a 1000 ml high-pressure container equipped with magnetic stirring, a thermometer, and a vent tube Inside the reactor;

[0027] (2) Add 2 grams of 5% Pd / C in the reactor, close the reactor, replace it with nitrogen for 3 times, feed hydrogen to make the pressure reach 0.4Mpa, heat up to 50°C while stirring, continue feeding hydrogen, After the pressure in the reaction kettle was raised to 0.5Mpa, the reaction was carried out for 20 hours, and the HPLC detection reaction was complete, and the temperature was cooled to room temperature to obtain the reaction solution;

[0028] (3) Pour out the reaction solution in step (2), filter and recover the catalyst, take the filtrate, acidify it to pH 1~2 with 30% hydrochloric acid, absorb the acidic macroporous resin, collect the effl...

Embodiment 2

[0030] (1) 50 grams of polychlorinated pyridine-2-formic acid waste mixture, 400 ml of water, and 140 grams of 30% sodium hydroxide are mixed evenly, filtered, and the filtrate is taken, and poured into a 1000 ml high-pressure container equipped with a magnetic stirrer, a thermometer, and a vent tube Inside the reactor;

[0031] (2) Add 5 grams of Ri-Ni to the reactor, seal the reactor, replace it with nitrogen for 3 times, feed hydrogen to make the pressure reach 0.4Mpa, raise the temperature to 80°C while stirring, continue to feed hydrogen, and make the reactor After the pressure inside rose to 0.5Mpa, the reaction was carried out for 24 hours, and the HPLC detection reaction was complete, and the temperature was cooled to room temperature to obtain the reaction solution;

[0032] (3) Pour out the reaction solution of step (2), filter and recover the catalyst, take the filtrate, acidify it to PH1~2 with 50% sulfuric acid, absorb the effluent through acidic macroporous resin...

Embodiment 3

[0034] (1) 50 grams of polychlorinated pyridine-2-formic acid waste mixture, 400 ml of water, and 139.6 grams of 30% sodium hydroxide are mixed uniformly, filtered, and the filtrate is taken, and poured into a 1000 ml high-pressure container equipped with magnetic stirring, a thermometer, and a vent tube Inside the reactor;

[0035] (2) Add 1 gram of 10% Pd / C to the reactor, close the reactor, replace it with nitrogen for 3 times, feed hydrogen to make the pressure reach 0.2Mpa, heat up to 100°C while stirring, continue feeding hydrogen, After maintaining the pressure in the reactor at 0.2Mpa, react for 30 hours, HPLC detects that the reaction is complete, cool down to room temperature, and obtain a reaction solution;

[0036] (3) Pour out the reaction solution in step (2), filter and recover the catalyst, take the filtrate, acidify it to pH 1~2 with 30% hydrochloric acid, absorb the acidic macroporous resin, collect the effluent; dehydrate the effluent to dryness , add 200ml...

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PUM

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Abstract

The invention discloses a method for preparing pyridine-2-formic acid by hydrogenation reduction of a poly chloro pyridine-2-formic acid mixture, belonging to the technical field of chemical waste recycling and reusing. Under the conditions of specific temperature, pressure and PH value, and the like, through catalytic hydrogenation, chlorine on a pyridine ring is removed, and the pyridine-2-formic acid is prepared. A clean and environment-friendly catalytic hydrogenation process is used, hydrogenation reduction with high selectivity is performed on the poly chloro pyridine-2-formic acid mixture, and the pyridine-2-formic acid is prepared; highly toxic dangerous articles such as a reducing agent hydrazine and dichloromethane are not used in a production process, reaction conditions are mild, a device is simple, the operation is simple and convenient, the cost is low, zero emission in pyridine-2-formic acid production is realized, the popularization and application of a green chemical industry technology are quickened, and the method is suitable for treating the poly chloro pyridine-2-formic acid mixture with high impurity content, and has obvious economic advantages and environmental protection advantages.

Description

technical field [0001] The invention belongs to the technical field of chemical waste recovery and reuse, and in particular relates to a method for preparing pyridine-2-carboxylic acid through hydrogenation reduction of polychlorinated pyridine-2-carboxylic acid mixture. Background technique [0002] 3,6-Dichloropicolinic acid is an excellent herbicide for broadleaf weeds and is widely used worldwide. Polychloropyridine-2-carboxylic acid mixture is a solid waste produced during the electrolysis of 3,6-dichloropicolinic acid from 3,4,5,6-tetrachloropicolinic acid. [0003] The composition of the polychloropyridine-2-carboxylic acid mixture is complex, generally containing 20-60% of 3,6-dichloropicolinic acid, and other chloropicolinic acids, and the composition changes greatly. Simple physical and chemical methods It is already difficult to purify, and it is generally treated as solid waste directly. However, this not only wastes some products, but also increases the treatme...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/79C07D213/803
CPCC07D213/79C07D213/803
Inventor 金克强李惠跃施祖伟徐巍
Owner ZHEJIANG AVILIVE CHEM CO LTD