CN1618785A - Production technology of 2-methyl-4-chloro-sodium phenoxy acetate - Google Patents
Production technology of 2-methyl-4-chloro-sodium phenoxy acetate Download PDFInfo
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- CN1618785A CN1618785A CN 200310110175 CN200310110175A CN1618785A CN 1618785 A CN1618785 A CN 1618785A CN 200310110175 CN200310110175 CN 200310110175 CN 200310110175 A CN200310110175 A CN 200310110175A CN 1618785 A CN1618785 A CN 1618785A
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Abstract
A process for preparing 2-methyl-4-chloro-sodium phenoxyacetate from O-phenylcresol, chloroacetic acid, sodium hydroxide and chlorine gas includes such steps as neutralizing reaction, etherifying reaction, chlorating reaction and salting reaction. It can be used as herbicide.
Description
Technical Field
The invention relates to a new chemical production process, in particular to a new process for producing 2-methyl-4-chloro-phenoxyethylate.
Background
Sodium 2-methyl-4-chloro-phenoxyacetate, known by the trade name 2 methyl 4 chloro (MCPA), is one of the most commonly used herbicide species. The herbicide is widely used in cereal crop fields such as rice, wheat and corn, and can prevent and kill annual and perennial broadleaf weeds and sedge weeds, and is also commonly used for preventing and killing flax, sugarcane, peas, lawns and uncultivated land weeds.
At present, enterprises producing 2-methyl-4-chloro (MPCA), namely 2-methyl-4-chloro-sodium phenoxyacetate in China all adopt the traditional production process, and the traditional process has the following defects: (1) the yield of chlorination reaction products is only about 50 percent. (2) The product has low purity (about 60 percent), contains more impurities (NaCL), is easy to absorb moisture and agglomerate, has poor solubility, can not be directly used for the production of 2-methyl-4-chloramine and ester products, can not reach the export standard, and ensures that the development of the products is limited to a certain extent. (3) The content of phenol is too high, about 4 percent, and dust and odor are large during mixing, so that a mixer is easy to stick to the wall. (4) Excessive byproducts, such as the byproduct 2 methyl 6 chlorophenoxyacetic acid reaches 18 percent, have adverse effects on the growth of partial corn varieties and can not meet the development and utilization requirements of related products and compound preparations thereof. (5) In the production process, the discharge of three wastes is excessive, the content of harmful substances is too high, serious environmental pollution is caused, and adverse effects are brought to the living environment and sustainable development of people. (6) Unreasonable material ratio, low conversion rate and excessive material consumption, and seriously restrict the further development of enterprises. Therefore, the improvement of the traditional domestic process for producing the 2-methyl-4-chloro-sodium phenoxyacetate is urgently needed.
Disclosure of Invention
The invention aims to provide a new process for producing the 2-methyl-4-chloro-sodium phenoxyacetate, which has high product yield and high purity, can reduce the consumption rate of raw materials and has low discharge of three wastes.
In order to realize the purpose of the invention, the technical scheme of the invention is as follows:
the invention takes o-cresol, chloroacetic acid, sodium hydroxide and chlorine as main raw materials, and is obtained by acid-base neutralization reaction, chlorination reaction and etherification reaction, and is characterized in that: the steps of chlorination reaction and etherification reaction are adjusted, the etherification reaction is carried out firstly, and then the chlorination reaction is carried out, and the method specifically comprises the following steps:
(1) firstly, performing neutralization reaction, namely placing chloroacetic acid and sodium hydroxide in a storage tank in a molar ratio of 1: 1, reacting for 4-5 hours at normal temperature, and cooling by using an ammonia refrigeration compressor to obtain chloroacetate;
(2) then carrying out etherification reaction: placing o-cresol and sodium hydroxide into an etherification reactor in a molar ratio of 1: 1 for neutralization reaction, starting to dropwise add sodium chloroacetate for etherification reaction when sodium phenolate is completely generated, controlling the temperature between 125 and 140 ℃, and reacting for 8 to 10 hours to obtain 2-methyl-sodium phenoxyacetate;
(3) then carrying out chlorination reaction, feeding the 2-methyl-sodium phenoxyacetate into a chlorination reaction kettle, adding hydrochloric acid for acidification, adding a dichloroethane medium, introducing chlorine at 75-80 ℃, and reacting for 5-6 hours;
(4) finally preparing a salt product: and (3) putting all products obtained in the chlorination reaction in the step (3) into a salt forming reaction kettle, adding sodium hydroxide for neutralization, and reacting for 4-5 hours at the temperature of 100 ℃ to obtain the 2-methyl-chloro-sodium phenoxyacetate.
In the etherification reaction (2), the feeding molar ratio of sodium o-cresol to sodium chloroacetate is 1: 1.08.
Chlorine is introduced from the bottom of the reaction kettle in the chlorination reaction in the step (3), so that the method of introducing chlorine from the top of the reaction kettle in the traditional process is changed. The flow rate is 15kg/h when chlorine is introduced, the reaction end point is based on gas chromatography, and the chlorine introduction is stopped after a target object is obtained.
And (3) after the chlorination reaction is finished, introducing steam, heating to remove the dichloroethane as a medium, and cooling and recycling the dichloroethane.
The product 2-methyl-4-chloro-sodium phenoxyacetate obtained by the production process can be prepared into powder or aqueous solution; if the powder is produced, heating to remove water, then crushing and mixing; if the water aqua is produced, water is added in proportion for preparation.
And a condenser is arranged in each reaction kettle, and condenses the materials carried out from the tail gas and recycles the materials after recovery.
The invention has the beneficial effects that:
(1) the consumption of raw materials is reduced: the cost of producing 2-methyl-4-chloro can be reduced by 0.35 ten thousand yuan per ton.
(2) The total yield of the product reaches more than 70 percent, the purity reaches more than 95 percent, and the product can be used for producing and developing 2-methyl-4-chloramine and ester series products, and all indexes of the product reach the standard through detection.
(3) The discharge amount of three wastes is obviously reduced, and the pollution to the environment is reduced. The process adopts circulating water in the production process, so that process wastewater is not discharged, and all water removed in the salt forming procedure is used for preparing the 2-methyl-4-chloro water agent.
(4) The new process adjusts the sequence of chlorination and etherification reactions, solves the problem of low conversion rate of the old process, the old process firstly chloridizes and then condenses, and adopts 10 percent (theoretical amount) of chlorine passing through the top, and the chlorine content in the material is measured to be 11 +/-0.5 percent, namely the material is qualified; meanwhile, the chlorine at the top only contacts the surface of the material, so the chlorination reaction effect is poor. The novel process adopts chlorine gas introduced from the bottom and adopts a gas chromatographic analysis method to determine the chlorine introduction amount, so that the chlorine introduction amount is accurate in the production process, ammonia gas directly enters the materials, and the chlorination effect is obviously improved; the old process has a chlorination conversion rate of only 70 percent, and the new process hasa conversion rate of 90 percent.
(5) The chlorination reaction of the new process adopts dichloroethane as a reaction medium, so that the utilization rate of chlorine is effectively improved, and the chlorination reaction speed is accelerated.
(6) The new process comprises etherification, chlorination and etherification reaction which are not added once, but are uniformly dripped, improves the accuracy of reaction conditions and greatly improves the yield of synthetic products.
(7) In the production process of the new process, the etherification, chlorination and salification are heating reactions, condensers are arranged on each reaction kettle in order to ensure that the reaction is a normal-pressure reaction, and when tail gas passes through the condensers, water in the condensers can condense materials brought out from the tail gas and can be recycled.
(8) The new process design completes the recycling of acid water, the whole internal circulation of materials, the utilization rate of raw materials is obviously improved, the unit consumption is reduced, and the problem that the old process is easy to cause environmental pollution due to the discharge of phenol-containing wastewater is solved.
(9) The new process improves the material pipeline, so that the material pipeline is more reasonable, the leakage of harmful materials is effectively avoided, the pollution to the environment is reduced, and the labor intensity is also reduced.
Drawings
FIG. 1 is a flow chart of the new process of the production; FIG. 2 is a gas chromatogram of chlorination reaction
The specific implementation mode is as follows:
for a better description of the present invention, reference is made to the following detailed description of the process flow diagram.
Examples
1. Neutralization step
580.6kg of chloroacetic acid and 247.8kg of sodium hydroxide are placed in a storage tank, dissolved by 1051kg of water, reacted for 4-5 hours at normal temperature, and cooled by an ammonia refrigeration compressor to obtain chloroacetate;
2. etherification step
(1) Neutralization reaction
616.2kg of o-cresol and 253.1kg of sodium hydroxide are put into an etherification reactor and dissolved by 363.5kg of water for neutralization reaction.
(2) Etherification reaction (conversion 90%)
After the reaction is finished, dropwise adding sodium chloroacetate, carrying out etherification reaction, controlling the temperature to be 125-140 ℃, and reacting for 8-10 hours to obtain 2-methyl-sodium phenoxyacetate;
feeding materials: 741.7kg of sodium o-cresol, 715.8kg of sodium chloroacetate and 1627.8kg of water.
In this step, 1414.5kg of 4.5% phenol-containing water was produced after distillation, and the product was cooled and recycled.
3. Chlorination process
(1) Acidification
1039.4kg of 2-methyl-sodium phenoxyacetate is sent into a chlorination reaction kettle, and 201.8kg of hydrochloric acid is added for acidification.
(2) Chlorination (conversion 90%)
Adding a dichloroethane medium after acidification, introducing chlorine at 75-80 ℃, and reacting for 5-6 hours;
the chlorination reaction result is measured by gas phase chromatography, and when the peak height of 2-methylphenoxyacetic acid is divided by the peak height of 2-methyl-4-methylphenoxyacetic acid and the value is between 0.04 and 0.18, the chlorination is qualified, as shown in figure 2.
1000kg of dichloroethane as a solvent is removed after the product is qualified, mother liquor is recovered after the product is settled, and the residual liquid contains HCL1189.7kg, NaCL1390kg, 22.5kg of water and 71.7kg of sodium chloroacetate, and the conversion rate of the chlorination reaction is calculated to be 90.44% by adopting an area ratio.
4. Salt formation procedure
And (3) putting all products obtained in the chlorination reaction in the step (3) into a salt forming reaction kettle, adding sodium hydroxide for neutralization, and reacting for 4-5 hours at the temperature of 100 ℃ to obtain the 2-methyl-4-chloro-phenoxysodium acetate. Removing water, pulverizing, mixing with sodium sulfate, and making into powder. The product performs in accordance with HG2610-94 standard.
Claims (7)
1. The new process for producing 2-methyl-4-chloro-phenoxyacetic acid sodium salt uses o-cresol, chloroacetic acid, sodium hydroxide and chlorine as main raw materials and is obtained by acid-base neutralization reaction, chlorination reaction and etherification reaction, and is characterized in that: the steps of chlorination reaction and etherification reaction are adjusted, the etherification reaction is carried out firstly, and then the chlorination reaction is carried out, and the specific production steps are as follows:
(1) firstly, carrying out neutralization reaction, placing chloroacetic acid and sodium hydroxide in a storage tank in a molar ratio of 1: 1, reacting for 4-5 hours at normal temperature, and cooling by using an ammonia refrigeration compressor to obtain sodium chloroacetate;
(2) then carrying out etherification reaction: firstly, adding o-cresol and sodium hydroxide in a molar ratio of 1: 1 into an etherification reactor for neutralization reaction, after the reaction is finished, dropwise adding sodium chloroacetate for etherification reaction, controlling the temperature to be 125-140 ℃, and reacting for 8-10 hours to obtain 2-methylphenoxy sodium acetate;
(3) then carrying out chlorination reaction, feeding the 2-methylphenoxy sodium acetate into a chlorination reaction kettle, adding hydrochloric acid for acidification, adding a dichloroethane medium, introducing chlorine at 75-80 ℃ and reacting for 5-6 hours;
(4) finally preparing a salt product: and (3) putting all products obtained in the chlorination reaction in the step (3) into a salt forming reaction kettle, adding sodium hydroxide for neutralization, and reacting for 4-5 hours at the temperature of 100 ℃ to obtain the 2-methyl-4-chloro-phenoxysodium acetate.
2. The new production process according to claim 1, wherein the feeding molar ratio of the o-cresol sodium to the sodium chloroacetate in the etherification reaction (2) is as follows: 1: 1.08.
3. The novel process of claim 1, wherein the chlorination reaction in step (3) is conducted by introducing chlorine gas from the bottom of the reaction vessel instead of introducing chlorine gas from the top of the reaction vessel as in the conventional process.
4. The process according to claim 1, wherein the chlorine gas is introduced into the chlorination reaction in step (3) at a flow rate of 15 KG/h.
5. The new process for production as claimed in claim 1, wherein after the chlorination reaction in step (3) is completed, steam is introduced to heat and remove the dichloroethane as a medium, and the dichloroethane is cooled and recovered for recycling.
6. The new production process as claimed in claim 1, wherein the product 2-methyl-4-chloro-sodium phenoxyacetate obtained by the production process can be prepared into powder or aqueous solution; if the powder is produced, heating to remove water, then crushing and mixing; if the water aqua is produced, water is added in proportion for preparation.
7. The novel production process as claimed in claim 1, wherein a condenser is installed in each reaction kettle, and the condenser condenses the materials carried out from the tail gas and recycles the materials after recovery.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN 200310110175 CN1618785A (en) | 2003-11-20 | 2003-11-20 | Production technology of 2-methyl-4-chloro-sodium phenoxy acetate |
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| CN 200310110175 CN1618785A (en) | 2003-11-20 | 2003-11-20 | Production technology of 2-methyl-4-chloro-sodium phenoxy acetate |
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Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102295561A (en) * | 2011-07-15 | 2011-12-28 | 江苏健谷化工有限公司 | Preparation method of 2-ethylhexyl (4-chloro-2-methylphenoxy)acetate |
| CN103058855A (en) * | 2011-10-20 | 2013-04-24 | 上海泰禾化工有限公司 | Method for synthesizing phenoxyacetic acid derivative |
| CN103304405A (en) * | 2013-06-26 | 2013-09-18 | 山东潍坊润丰化工有限公司 | Selective chlorination method |
| CN103351295A (en) * | 2013-06-04 | 2013-10-16 | 安徽兴隆化工有限公司 | 2-methyl-4-chlorophenoxyacetic acid preparation technology |
| CN107698440A (en) * | 2017-09-30 | 2018-02-16 | 安徽华星化工有限公司 | A kind of synthetic method of the chlorophenoxyacetic acid of 2 methyl 4 |
| CN107824017A (en) * | 2017-09-30 | 2018-03-23 | 安徽华星化工有限公司 | MCPA,MCP,methoxone produces exhaust gas treating method |
| CN108530284A (en) * | 2018-04-08 | 2018-09-14 | 湘潭大学 | The preparation method of o-methyl-benzene fluoroacetic acid |
| CN108727196A (en) * | 2018-07-23 | 2018-11-02 | 安徽华星化工有限公司 | A method of producing the esters of 2-methyl-4-chlorophenoxyacetic acid |
-
2003
- 2003-11-20 CN CN 200310110175 patent/CN1618785A/en active Pending
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102295561A (en) * | 2011-07-15 | 2011-12-28 | 江苏健谷化工有限公司 | Preparation method of 2-ethylhexyl (4-chloro-2-methylphenoxy)acetate |
| CN103058855A (en) * | 2011-10-20 | 2013-04-24 | 上海泰禾化工有限公司 | Method for synthesizing phenoxyacetic acid derivative |
| WO2013056488A1 (en) * | 2011-10-20 | 2013-04-25 | 上海泰禾化工有限公司 | Phenoxyacetic acid derivative synthesis method |
| CN103058855B (en) * | 2011-10-20 | 2015-07-01 | 上海泰禾化工有限公司 | Method for synthesizing phenoxyacetic acid derivative |
| CN103351295A (en) * | 2013-06-04 | 2013-10-16 | 安徽兴隆化工有限公司 | 2-methyl-4-chlorophenoxyacetic acid preparation technology |
| CN103351295B (en) * | 2013-06-04 | 2016-12-28 | 安徽兴隆化工有限公司 | A kind of 2-first-4-chlorophenoxyacetic acid preparation technology |
| 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 |
| CN107698440A (en) * | 2017-09-30 | 2018-02-16 | 安徽华星化工有限公司 | A kind of synthetic method of the chlorophenoxyacetic acid of 2 methyl 4 |
| CN107824017A (en) * | 2017-09-30 | 2018-03-23 | 安徽华星化工有限公司 | MCPA,MCP,methoxone produces exhaust gas treating method |
| CN108530284A (en) * | 2018-04-08 | 2018-09-14 | 湘潭大学 | The preparation method of o-methyl-benzene fluoroacetic acid |
| CN108727196A (en) * | 2018-07-23 | 2018-11-02 | 安徽华星化工有限公司 | A method of producing the esters of 2-methyl-4-chlorophenoxyacetic acid |
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