CN101941903A - Method for producing 2-methyl-4-MCPA - Google Patents
Method for producing 2-methyl-4-MCPA Download PDFInfo
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- CN101941903A CN101941903A CN 201010269440 CN201010269440A CN101941903A CN 101941903 A CN101941903 A CN 101941903A CN 201010269440 CN201010269440 CN 201010269440 CN 201010269440 A CN201010269440 A CN 201010269440A CN 101941903 A CN101941903 A CN 101941903A
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Abstract
The invention discloses a method for producing 2-methyl-4-MCPA. In the presence of catalyst dimethylamino pyridine and dimethyl formamide, 2-methyl -phenoxy acetic acid introduces chlorine into sodium hydroxide aqueous solution to react so as to obtain the finished product of the 2-methyl-4-MCPA. The invention has the advantages of simple operation and good environment protection property, the yield of the 2-methyl-4-MCPA is improved to be above 95%, and the content of effective ingredients is above 97%.
Description
Technical field:
The present invention relates to a kind of production method of weedicide 2-methyl-4-chlorophenoxyacetic acid.
Background technology
2-methyl-4-chlorophenoxyacetic acid is one of organic herbicide kind of using the earliest, still is the basic kind of weedicide so far.2 first, 4 chlorine belong to fine herbicide, have characteristics such as efficient, low toxicity, low residue, environmentally safe, are hormone weedkiller, also are plant-growth regulator.The present following method of industrial common employing:
1,2-methylphenol chlorination condensation method, i.e. 2-methylphenol chlorination under its molten state is produced the 2-methyl-4-chlorophenol and the Mono Chloro Acetic Acid condensation that obtain subsequently.
2, the condensation under alkaline condition of 2-methylphenol and Mono Chloro Acetic Acid generates the 2-methyl phenoxy acetic acid, uses chlorinated with chlorine to produce in aqueous phase again.
Last method has many defectives, dioxin is a highly toxic substance to the most important thing is this method can not to guarantee preparation do not have the 2-methyl-4-chlorophenoxyacetic acid Er of dioxin-like compound (dioxines) fully, even just people and animals and plants are caused murder by poisoning under the extremely low amount of every ppb-.Secondly, the product active constituent content for preparing with this method can only reach 56～70%, and the required organic solvent toluene/ethylene dichloride purification process of high-quality product has not only increased cost, but also has strengthened the pollution to environment.In 2-methyl-4-chlorophenol production and use, exist the bad smell of (many) chlorophenols not only producers directly to be constituted danger, and surrounding environment is caused serious air pollution problems inherent.On the contrary, back one method can prevent the generation of dioxin, and has overcome the other defect of last method, and three wastes treatment capacity is less.The still not high shortcoming of product purity that obtains at water post chlorization method, some enterprises have developed in organic solvent toluene/ethylene dichloride chlorating method, though product purity can reach 95%, yield can only reach 75%, also wants the product of some low levelss of by-product.And the use of organic solvent toluene/ethylene dichloride not only increased cost, but also strengthened the pollution to environment.
Summary of the invention:
The object of the present invention is to provide a kind of method method of easy to operate, production 2-methyl-4-chlorophenoxyacetic acid that the feature of environmental protection is good.
Technical solution of the present invention is:
A kind of method of producing 2-methyl-4-chlorophenoxyacetic acid is characterized in that: the 2-methyl phenoxy acetic acid feeds chlorine reaction and obtains finished product 2-first-4-chlorophenoxyacetic acid in the presence of catalyzer Dimethylamino pyridine and dimethyl formamide in aqueous sodium hydroxide solution.
The 2-methyl phenoxy acetic acid is dissolved in the aqueous sodium hydroxide solution, adds catalyzer Dimethylamino pyridine and dimethyl formamide, feed chlorine reaction, decrease temperature crystalline after reaction is finished obtains the finished product 2-methyl-4-chlorophenoxyacetic acid by filtering separation, drying then.
The mass ratio of 2-methyl phenoxy acetic acid and complex solvent is 1: 1～100; The mass ratio of catalyzer Dimethylamino pyridine and dimethyl formamide is 1: 1～10; The mass ratio of the total mass of catalyzer Dimethylamino pyridine and dimethyl formamide and 2-methyl phenoxy acetic acid is 1: 50～800; Feeding the chlorine reaction temperature is 10～100 ℃; The molar ratio of the chlorine total amount of 2-methyl phenoxy acetic acid and feeding is 1: 1～1.7; The weight concentration of aqueous sodium hydroxide solution is 0.1～50%.
The present invention adopts in aqueous sodium hydroxide solution (water), regulate the solubleness of raw material 2-methyl phenoxy acetic acid, product 2-methyl-4-chlorophenoxyacetic acid by the pH value of conditioned reaction system, guaranteeing that raw material 2-methyl phenoxy acetic acid has under the prerequisite of enough solubleness, make the product 2-methyl-4-chlorophenoxyacetic acid of generation break away from reaction system with sedimentary form, thereby avoid further contacting chlorine and be reacted into by-product 2-methyl-4,6-dichlorphenoxyacetic acid.
The present invention adopts composite catalyst Dimethylamino pyridine and dimethyl formamide, can make chlorination reaction with one more stably speed carry out, can position chlorination again, reduce 2-methyl-6-dichlorphenoxyacetic acid, 2-methyl-4, the generation of 6-dichlorphenoxyacetic acid by-product.
The present invention be advantageous in that:
1, yield height.In the yield of 2-methyl phenoxy acetic acid 2-methyl-4-chlorophenoxyacetic acid up to more than 95%.
2, good product quality.Effective constituent 2-methyl-4-chlorophenoxyacetic acid content is up to more than 97%, and Han dioxin never.
3, easy and simple to handle, environment-friendly advantage is obvious.Do not use organic solvents such as toluene, ethylene dichloride, no chlorinated phenol peculiar smell.
Reduce cost.Along with the raising of yield and the reduction of raw material consumption, can realize the reduction of production cost.
The invention will be further described below in conjunction with embodiment.
Embodiment:
Embodiment 1:
In the 500ml reaction flask, add 2-methyl phenoxy acetic acid 41g (content 98%, 0.242mol), Dimethylamino pyridine 0.5g (content 99%), dimethyl formamide 2.5g (content 99%) and 8% aqueous sodium hydroxide solution 363g (0.726mol), stirring and dissolving under the room temperature.Keep 20～25 ℃ of temperature of reaction, feed the about 28g of chlorine with the speed of 5～10kg/hr in material, HPLC monitoring raw material 2-methyl phenoxy acetic acid content was less than 1% o'clock, and reaction finishes.Constantly there is the 2-methyl-4-chlorophenoxyacetic acid solid to separate out in the logical chlorine process.Drip concentrated hydrochloric acid material pH is transferred to 1～2, be cooled to 0～5 ℃, filter, obtain the 2-methyl-4-chlorophenoxyacetic acid of 47.6g white solid behind the filtration cakes torrefaction, effective constituent 2-methyl-4-chlorophenoxyacetic acid content 97.4%, yield 95.5%.
Embodiment 2:
A kind of method of producing 2-methyl-4-chlorophenoxyacetic acid, the 2-methyl phenoxy acetic acid is dissolved in the aqueous sodium hydroxide solution, add catalyzer Dimethylamino pyridine and dimethyl formamide, feed chlorine reaction, decrease temperature crystalline after reaction is finished obtains the finished product 2-methyl-4-chlorophenoxyacetic acid by filtering separation, drying then.
The mass ratio of 2-methyl phenoxy acetic acid and complex solvent is 1: 1～100 (examples 1: 1,1: 50,1: 100); The mass ratio of catalyzer Dimethylamino pyridine and dimethyl formamide is 1: 1～10 (examples 1: 1,1: 5,1: 10); The mass ratio of the total mass of catalyzer Dimethylamino pyridine and dimethyl formamide and 2-methyl phenoxy acetic acid is 1: 50～800 (examples 1: 50,1: 400,1: 800); Feeding the chlorine reaction temperature is 10～100 ℃ (10 ℃, 50 ℃, 100 ℃ of examples); The molar ratio of the chlorine total amount of 2-methyl phenoxy acetic acid and feeding is 1: 1～1.7 (examples 1: 1,1: 1.5,1: 1.7); The weight concentration of aqueous sodium hydroxide solution is 0.1～50% (example 0.1%, 25%, 50%).
Claims (3)
1. method of producing 2-methyl-4-chlorophenoxyacetic acid, it is characterized in that: the 2-methyl phenoxy acetic acid feeds chlorine reaction and obtains finished product 2-first-4-chlorophenoxyacetic acid in the presence of catalyzer Dimethylamino pyridine and dimethyl formamide in aqueous sodium hydroxide solution.
2. the method for production 2-methyl-4-chlorophenoxyacetic acid according to claim 1, it is characterized in that: the 2-methyl phenoxy acetic acid is dissolved in the aqueous sodium hydroxide solution, add catalyzer Dimethylamino pyridine and dimethyl formamide, feed chlorine reaction, decrease temperature crystalline after reaction is finished obtains the finished product 2-methyl-4-chlorophenoxyacetic acid by filtering separation, drying then.
3. the method for production 2-methyl-4-chlorophenoxyacetic acid according to claim 1 is characterized in that: the mass ratio of 2-methyl phenoxy acetic acid and complex solvent is 1: 1～100; The mass ratio of catalyzer Dimethylamino pyridine and dimethyl formamide is 1: 1～10; The mass ratio of the total mass of catalyzer Dimethylamino pyridine and dimethyl formamide and 2-methyl phenoxy acetic acid is 1: 50～800; Feeding the chlorine reaction temperature is 10～100 ℃; The molar ratio of the chlorine total amount of 2-methyl phenoxy acetic acid and feeding is 1: 1～1.7; The weight concentration of aqueous sodium hydroxide solution is 0.1～50%.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2010102694409A CN101941903B (en) | 2010-09-01 | 2010-09-01 | Method for producing 2-methyl-4-MCPA |
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| CN2010102694409A CN101941903B (en) | 2010-09-01 | 2010-09-01 | Method for producing 2-methyl-4-MCPA |
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| CN101941903A true CN101941903A (en) | 2011-01-12 |
| CN101941903B CN101941903B (en) | 2012-11-07 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103304405A (en) * | 2013-06-26 | 2013-09-18 | 山东潍坊润丰化工有限公司 | Selective chlorination method |
| CN104447290A (en) * | 2014-12-15 | 2015-03-25 | 常熟市新腾化工有限公司 | Method for preparing 2,4-dichlorophenoxyacetic acid |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1485310A (en) * | 2002-09-24 | 2004-03-31 | 佳木斯黑龙农药化工股份有限公司 | Process for preparing high-purity 2-methyl-4-chloro phenoxyacetic acid |
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2010
- 2010-09-01 CN CN2010102694409A patent/CN101941903B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1485310A (en) * | 2002-09-24 | 2004-03-31 | 佳木斯黑龙农药化工股份有限公司 | Process for preparing high-purity 2-methyl-4-chloro phenoxyacetic acid |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103304405A (en) * | 2013-06-26 | 2013-09-18 | 山东潍坊润丰化工有限公司 | Selective chlorination method |
| CN103304405B (en) * | 2013-06-26 | 2015-09-16 | 山东潍坊润丰化工股份有限公司 | A kind of method of selective chlorination |
| CN104447290A (en) * | 2014-12-15 | 2015-03-25 | 常熟市新腾化工有限公司 | Method for preparing 2,4-dichlorophenoxyacetic acid |
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| CN101941903B (en) | 2012-11-07 |
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