Preparation method of 3,4,5,6-tetrachloropyridine-2-carboxylic acid

A technology of clopicolinic acid and clopyralid, applied in the field of preparation of 3,4,5,6-tetraclopyralid, capable of solving problems such as environmental pollution and undiscovered preparation methods

Active Publication Date: 2015-05-27
HUNAN BIDE BIOTECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The preparation method of 3,4,5,6-tetrachloropicolinic acid has not found relevant literature reports
[0012] How to further process the isomers of other non-effective pesticide components in the waste residue of amiloride into resource utilization, so that it cannot be treated as waste residue and cause environmental pollution, has always been a problem for major amiloride manufacturers The problem
At present, there are no relevant reports in domestic and foreign literature and patents

Method used

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  • Preparation method of 3,4,5,6-tetrachloropyridine-2-carboxylic acid
  • Preparation method of 3,4,5,6-tetrachloropyridine-2-carboxylic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0054] Preparation of 3,4,5,6-tetrachloropicolinic acid from 4-amino-3,5,6-trichloropicolinic acid (content above 95%)

[0055] Add 300g concentrated hydrochloric acid (36%, 2.95mol), 200g toluene, 40g 4-amino-3,5,6-tetrachloropicolinic acid (HPLC 98.5%, moisture<0.5%, 0.16mol) to the 1000ml flask successively, ice Water-cooled bath to between 0 ~ 5 ℃, stir evenly, quickly add 13.7g sodium nitrite (0.19mol), continue stirring for 30 minutes;

[0056] Below 5°C, add 19.0g of cuprous chloride (0.19mol), program the temperature rise, every 30 minutes to increase the temperature by 10°C, and continue to heat up to 50-55°C, HPLC analysis of 4-amino-3,5,6-tri When the content of clopicolinic acid is lower than 1.0%, the reaction ends.

[0057] Cool the water bath to below 30°C, then slowly add metered 40% potassium hydroxide solution dropwise to neutralize until the pH is between 8 and 9, filter, and the filter cake is washed with a small amount of water to precipitate copper hydro...

Embodiment 2

[0059] From the mixture of 4-amino-3,5,6-trichloropyridinecarboxylic acid ammonium salt and 6-amino-3,4,5-tetrachloropyridinecarboxylic acid ammonium salt (that is, the above residue I mainly contains 88%-92% 6-amino-3,4,5-trichloropicolinate ammonium salt, the rest is 4-amino-3,5,6-trichloroformic acid ammonium salt) to prepare 3,4,5,6-tetrachloropicolinic acid:

[0060] Prioritize drying the raw materials of the above residue I until the water content is <0.5% before the following experiments can be carried out.

[0061] Add 300g of concentrated hydrochloric acid (36%, 2.95mol), 200g of toluene, 40g of 4-amino-3,5,6-tetrachloropicolinate ammonium salt and 6-amino-3,4,5-tetrachloropyridine to a 1000ml flask successively Ammonium picolinate salt mixture (ammonium salt of 6-amino-3,5,6-triclopyridine is 85%, ammonium 4-amino-3,5,6-triclopyridine is 15%, 0.15 mol), ice water cooling bath to 15 ~ 25 ℃, stir evenly, quickly add 11.6g sodium nitrite (0.0.17mol), continue to stir f...

Embodiment 3

[0065] From 3-amino-4,5,6-trichloropicolinic acid, 4-amino-3,4,6-trichloropicolinic acid, 5-amino-3,4,6-trichloropicolinic acid and 6-amino- 3,4,5-Triclopyridine carboxylic acid mixture (that is, the above residue II, mainly contains 85%-90% of 3-amino-4,5,6-trichloroformic acid and 5-amino-3,4,6- A mixture of clopyralid, 6%-8% of 6-amino-3,4,5-trichloropicralic acid and the remainder 4-amino-3,5,6-trichloropicralic acid) to prepare 3,4,5 ,6-Tetrachloropicolinic acid:

[0066] Prioritize the drying treatment of the above-mentioned residue II raw materials, and the following experiments can only be carried out when the moisture content is <0.5%. Add 300g concentrated hydrochloric acid (36%, 2.95mol), 200g toluene, 40g 4-amino-3,5,6-tetrachloropicolinic acid, 3-amino-4,5,6-trichloropicolinic acid to a 1000ml flask in turn Mixture with 5-amino-3,4,6-tetrachloropicolinic acid (the ratio of 3-amino-4,5,6-trichloropicolinic acid to 5-amino-3,4,6-trichloropicolinic acid is 90 %, t...

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Abstract

The invention provides a preparation method of 3,4,5,6-tetrachloropyridine-2-carboxylic acid. The method comprises the following steps: with waste residue generated in production of picloram or waste obtained after further purification of the waste residues generated in production of the picloram as raw material, adding nitrite for diazotization by the effects of strong acid and an inert diluent; adding a chlorine substituting agent for chlorination reaction to prepare the 3,4,5,6-tetrachloropyridine-2-carboxylic acid. A small amount of other isomerides generated during an ammonolysis process of tetrachloropyridine-2-carboxylic acid during circular processing and treatment of the method can be used for transforming non-pesticide components in the waste residues into raw production materials with practical values, so that the emission of the waste residues is reduced as far as possible. The prepared 3,4,5,6-tetrachloropyridine-2-carboxylic acid is higher than 95% in effective content and can satisfy the requirements on raw materials for industrial production of the picloram.

Description

technical field [0001] The invention belongs to the field of synthesis of tetrachloropicolinic acid, in particular to a preparation method of 3,4,5,6-tetrachloropicolinic acid. Background technique [0002] 3,4,5,6-tetrachloropicolinic acid, the trade name is abbreviated as tetraclopyridine, the appearance of white powder, the melting point of 210 ~ 214 ℃. It is mainly used in the field of pesticides, such as the industrial preparation of the herbicide amiloride. Amiloride, whose chemical name is 4-amino-3,5,6-trichloropicralic acid, is a systemic herbicide that widely acts on broad-leaved weeds, Datura plants and other weeds. It has the characteristics of low toxicity, high selectivity, small residue and short residue cycle, etc., and has broad market prospects. [0003] 3,4,5,6-tetrachloropicolinic acid is generally used as raw material to prepare 4-amino-3,5,6-trichloropicolinic acid. No relevant literature reports have been found on the preparation method of 3,4,5,6-t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/803C07D213/79
CPCC07D213/79C07D213/803
Inventor 章清华王宇付林李琼
Owner HUNAN BIDE BIOTECH
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