Preparation method of high-purity 2,4-D

A high-purity, 4-D technology, applied in the preparation of organic compounds, carboxylate, carboxylate, etc., can solve the problems of cumbersome operation steps, long reaction time, large process water consumption, etc., and achieve simplified process Steps, increase product yield, shorten the effect of reaction time

Active Publication Date: 2013-10-16
山东科源化工有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] However, the existing 2,4-D production process requires large water consumption, cumbersome operation steps and long reaction time

Method used

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  • Preparation method of high-purity 2,4-D

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] A preparation method of high-purity 2,4-D, comprising the steps of:

[0024] (1) 98.5% 2,4-dichlorophenol 1650kg, and 32% liquid caustic soda, add water 100kg, react at 60°C for 2 hours to make 2,4-dichlorophenol sodium, wherein the 2,4-dichlorophenol and the The molar ratio of said liquid alkali is 1:1.1;

[0025] (2) 1150 kg of chloroacetic acid with a purity of 99% was directly reacted with the 2,4-dichlorophenate sodium at pH=9-11, 100-120°C for 3-4 hours to obtain 2,4-D sodium salt. The mol ratio of said chloroacetic acid and said 2,4-dichlorophenate sodium is 1.3:1;

[0026] (3) The 2,4-D sodium salt is press-filtered and acidified for 2-3 hours to form a 2,4-D crude product; the acidification process is as follows: add 2,4-D sodium salt to water and heat to 80 At 90°C, under stirring conditions, add industrial hydrochloric acid to adjust PH=9-11, stop heating, stir until the crude product of 2,4-D precipitates after cooling, and the mass ratio of 2,4-D sodium s...

Embodiment 2

[0030] A preparation method of high-purity 2,4-D, comprising the steps of:

[0031] (1) Preparation of sodium 2,4-dichlorophenate: react 2,4-dichlorophenol with a concentration of 98.5% and liquid caustic soda with a concentration of 32% at 65°C for 2 hours to prepare sodium 2,4-dichlorophenate ; Wherein the molar ratio of the 2,4-dichlorophenol and the liquid caustic soda is 1:1.2, the yield of the 2,4-dichlorophenol sodium is 99.5%;

[0032] (2) Preparation of 2,4-D sodium salt: react chloroacetic acid with a purity of 99% directly with the 2,4-dichlorophenate sodium at pH=10-11, 120°C for 3-4 hours to obtain 2,4-D -D sodium salt, the molar ratio of the chloroacetic acid to the 2,4-dichlorophenate sodium is 1.4:1, and the yield of the 2,4-D sodium salt is 98%;

[0033] (3) Preparation of 2,4-D crude product: the 2,4-D sodium salt was press-filtered and acidified for 3 hours to form 2,4-D crude product, and the yield of the 2,4-D crude product was 99.5% The acidification pr...

Embodiment 3

[0037] A preparation method of high-purity 2,4-D, comprising the steps of:

[0038] (1) Preparation of sodium 2,4-dichlorophenate: react 2,4-dichlorophenol with a concentration of 98.5% and liquid caustic soda with a concentration of 32% at 50°C for 2 hours to prepare sodium 2,4-dichlorophenate ; Wherein the molar ratio of the 2,4-dichlorophenol and the liquid caustic soda is 1:1, the yield of the 2,4-dichlorophenol sodium is 99.5%;

[0039] (2) Preparation of 2,4-D sodium salt: directly react chloroacetic acid with a purity of 99% with the 2,4-dichlorophenate sodium at pH=9-10,100°C for 3-4 hours to obtain 2,4-D -D sodium salt, the molar ratio of the chloroacetic acid to the 2,4-dichlorophenate sodium is 1.2:1, and the yield of the 2,4-D sodium salt is 98%;

[0040] (3) Preparation of 2,4-D crude product: the 2,4-D sodium salt was press-filtered and acidified for 3 hours to form 2,4-D crude product, and the yield of the 2,4-D crude product was 99.5% ; The acidification proc...

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Abstract

The invention discloses a preparation method of high-purity 2,4-D. The preparation method comprises the following steps: (1) preparing 2,4-bitionolate; (2) enabling chloroacetic acid and the 2,4-bitionolate to directly react under the alkaline condition to obtain 2,4-D sodium salt; (3) achieving pressure filtration and acidification of the 2,4-D sodium salt to form a 2,4-D crude product; (4) rinsing- pressure-filtering and drying the 2,4-D crude product to obtained to the high-purity 2,4-D product. The preparation method provided by the invention can effectively reduce the process water consumption, simplify the process steps, greatly shorten the reaction time and improve the product yield.

Description

technical field [0001] The invention relates to a preparation method of 2,4-D, in particular to a preparation method of high-yield and high-purity 2,4-D. Background technique [0002] 2,4-D, namely 2,4-dichlorophenoxyacetic acid, is a representative synthetic auxin, and 2,4-D is a phenoxyacetic acid hormone-type selective herbicide, mainly used for post-emergence stems Leaf treatment, such as wheat, barley, highland barley, corn, bone, sorghum and other gramineous crop fields and gramineous pasture land, control and control of Artemisia sorenzo, chickweed, quinoa, shepherd's purse, ion grass, humulus, vetch, bitter barley Broad-leaved weeds such as cocklebur, field bindweed, purslane, etc., are ineffective against gramineous weeds. The usual dosage is 40-60ml of 72% 2,4-D butyl ester EC per mu; crops such as cotton and soybean are sensitive to this drug, and a certain isolation zone should be kept when using it. At the same time, 2,4-D acid has the effect of phytohormone, ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C59/70C07C51/02C07C51/367C07C51/42
Inventor 曲江升蒋一博史英慧
Owner 山东科源化工有限公司
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