CN101270062B - The production process of acetochlor by methylene method - Google Patents

Abstract

The present invention relates to a preparation process of acetochlor in a methylene method, and is characterized in that the production process comprises the following steps: (1) under the influence of a catalyst and a stabilizer, 2-methyl-6-diethylaniline and paraformaldehyde have dehydration reaction in non-aromatic solvent cyclohexane, petroleum ether or the mixture of the cyclohexane and the petroleum ether, to prepare 2-methyl-6-ethyl-N-methylene aniline that requires no purification for the reaction in the next step; (2) under the condition with non-aromatic solvents or without solvents, the prepared 2-methyl-6-ethyl-N-methylene aniline and chloroacetic chloride have acylation reaction; then the products prepared in the acylation reaction and anhydrous alcohol react to prepare the crude product; and the acetochlor with more than 93 percent of the acetochlor content can be separated and prepared.

Description

The production process of acetochlor by methylene method

technical field

The invention relates to the field of pesticides, in particular to a novel production process of acetochlor-methylidene method.

Background technique

Acetochlor, the common name is Acetochlor, and the chemical name is 2'-methyl-6'-ethyl-N-(ethoxymethyl)-2-chloroacetanilide, which is the choice researched and developed by Monsanto Company of the United States Sexual pre-emergent herbicide, can be absorbed by the young shoots and young roots of weeds, inhibit the protein synthesis of weeds and cause the death of weeds, and its effective period in the soil can reach about 2 months. The chemical structural formula of acetochlor is as follows:

The present domestic acetochlor synthetic method is mainly the chlorinated ether method, and this method comprises the steps: (1) in xylene solvent, 2,6-methylethylaniline is reacted with chloroacetic acid and phosphorus trichloride to generate 2, 6-methylethyl chloroacetanilide; (2) ethanol and polyoxymethylene react in the presence of hydrochloric acid to obtain chloromethyl ethyl ether; (3) 2,6-methylethyl chloroacetylanilide and step (2) preparation The obtained chloromethyl ethyl ether is reacted in an alkaline medium to obtain acetochlor. The problem that this method exists mainly is: adopt xylene to make solvent in the reaction, " three wastes " discharges a lot in the production process, and environmental pollution is big; Contain carcinogen chloromethyl ethyl ether in the obtained acetochlor product simultaneously, to the product's safety Security has a big impact and therefore affects the use of the product. In addition, although there are individual reports abroad on the production of amide compounds by the ethylene aniline method, there is also a problem of using a large number of aromatic solvents such as xylene in the production process, which leads to large solvent consumption, high cost, and great environmental pollution. And the yield is lower.

In order to overcome the above problems, the present invention provides a novel acetochlor methylene method production process, which uses non-aromatic hydrocarbons as solvents, has low toxicity, and greatly reduces the discharge of "three wastes" and environmental pollution; and through catalyst The use of the stabilizer and the stabilizer improves the yield of acetochlor, reduces waste discharge, reduces production costs, and significantly improves economic benefits.

Contents of the invention

The object of the present invention is to provide a kind of novel acetochlor methylene method production technology, this methylene method production technology comprises the steps:

1. Under the action of catalyst and stabilizer, dehydrate 2-methyl-6-ethylaniline and paraformaldehyde in low-toxic non-aromatic solvent cyclohexane, petroleum ether or a mixture of cyclohexane and petroleum ether The reaction generates 2-methyl-6-ethyl-N-methylene aniline (methylene), the conversion rate is more than 97% (in terms of 2-methyl-6-ethylaniline), and the content is more than 98%; the product The next step reaction can be carried out without purification;

2. Under non-aromatic solvent or solvent-free conditions, make the obtained 2-methyl-6-ethyl-N-methylene aniline and chloroacetyl chloride carry out acylation reaction, and then make the acylation reaction product and anhydrous The crude product is obtained by ethanol reaction, and acetochlor is obtained by separation, the conversion rate is above 93% (calculated as 2-methyl-6-ethyl-N-methylene aniline), and the content of acetochlor is above 93%.

The reaction process is as follows:

Wherein the catalyst is preferably an organic base, an inorganic base or a mixture of an organic base and an inorganic base, wherein the organic base is preferably trimethylamine, triethylamine, tri-n-butylamine, pyridine or N-methylpyrrole, etc., and the inorganic base is preferably an alkali Metal hydroxides, alkali metal oxides or alkali metal carbonates, etc., such as sodium hydroxide, sodium carbonate, etc.

Among them, the stabilizer preferably uses transition metal powder or a compound of negative divalent sulfur or a mixture of transition metal powder and negative divalent sulfur compound, wherein the metal powder preferably uses iron powder, tin powder or zinc powder, and the compound of negative divalent sulfur preferably uses ( _NH4 ) _2S , _NH4HS or _Na2S .

In the case of using a mixture of transition metal powder and negative divalent sulfur compound, the molar ratio of transition metal powder to negative divalent sulfur compound is preferably 1:1-8:1.

Wherein the substance ratio (molar ratio) of the stabilizer to 2-methyl-6-ethylaniline is preferably 0.001-0.1:1.

When the non-aromatic solvent is a mixture of hexanaphthene and sherwood oil, if the quality of sherwood oil accounts for less than 20% of the mass of the mixture, then the non-aromatic solvent preferably accounts for 75-90% of the total reactant mass; if the mass of sherwood oil accounts for the mass of the mixture If the quality of petroleum ether accounts for 45-80% of the mass of the mixture, then the non-aromatic solvent preferably accounts for 45-60% of the total reactant mass ; If the quality of petroleum ether accounts for more than 80% of the mass of the mixture, the non-aromatic solvent preferably accounts for 35-50% of the total reactant mass.

Wherein, in the production process of methylene, the reaction temperature is preferably 40-100° C.; in the acylation process of methylene and chloroacetyl chloride, the reaction temperature is preferably 15-120° C.

Detailed ways:

The present invention will be further described below in conjunction with embodiment, but the present invention is by no means limited to following embodiment.

Example 1

Take 62g of 2-methyl-6-ethylaniline, add 150g of cyclohexane, 16g of 95% ethanol, 0.5g of stabilizer NH ₄ HS, 28g of paraformaldehyde, 0.15g of catalyst sodium hydroxide, and add into a 500ml four-necked bottle During the process, stir, heat up to 36°C and react for 50 minutes, then start water separation. After water separation, cyclohexane is distilled off to obtain 67.1 g of methylene, with a content of 99% and a conversion rate of 99.4%.

Take 60g of chloroacetyl chloride and 67.1g of methylene chloride, add them into a 500ml four-neck flask, stir, keep the temperature below 20°C, react for 2 hours, add 100g of absolute ethanol to react for 2 hours, and feed NH ₃ until the pH=7～ At about 9, solid ammonium chloride was filtered out, and cyclohexane was evaporated from the filtrate to obtain 122.5 g of acetochlor, with a content of 94.5% and a conversion rate of 94%.

Example 2

Get 2-methyl-6-ethylaniline 62g, add cyclohexane and petroleum ether mixed solvent 110g (petroleum ether quality accounts for 80%), 95% ethanol 16g, the stabilizer NH _HS and Add 0.3g of Fe powder, 28g of paraformaldehyde, and 0.5g of tri-n-butylamine into a 500ml four-neck flask and stir. After raising the temperature to 60°C and reacting for 40 minutes, water separation begins. After the water separation is completed, the solvent is evaporated to obtain formazan Fork 67.3g, content 99.1%, conversion rate 98.8%.

Take 62g of chloroacetyl chloride and 67.3g of methylene chloride, add them into a 500ml four-neck flask, stir, keep below 20°C, react for 2 hours, add 200g of absolute ethanol to react for 2 hours, and feed _NH3 until the pH is about 7~9 , filtered to obtain solid ammonium chloride, and the filtrate was distilled to remove cyclohexane and petroleum ether to obtain 121.9 g of acetochlor with a content of 94.2% and a conversion rate of 93.7%.

Example 3

Take 62g of 2-methyl-6-ethylaniline, add 60g of petroleum ether, 16g of 95% ethanol, 0.35g of stabilizer (NH ₄ ) ₂ S, 28g of paraformaldehyde, and 0.5g of pyridine into a 500ml four-necked bottle , stirred, heated up to 66° C. and reacted for 40 minutes, then began to divide the water. After the water was separated, the petroleum ether was distilled off to obtain 66.8 g of methylene, with a content of 99.3% and a conversion rate of 98.3%.

Take 60g of chloroacetyl chloride and 67g of methylene chloride, add them into a 500ml four-neck flask, stir, keep below 20°C, react for 2 hours, add 200g of absolute ethanol to react for 2 hours, and feed NH ₃ until the pH=7~9. Solid ammonium chloride was obtained by filtration, and petroleum ether was evaporated from the filtrate to obtain 122.2 g of acetochlor with a content of 95% and a conversion rate of 94.1%.

Example 4

Get 2-methyl-6-ethylaniline 62g, add cyclohexane and petroleum ether mixed solvent 80g (petroleum ether quality accounts for 50%) respectively, 95% ethanol 16g, stabilizer Sn powder 0.5g, paraformaldehyde 28g, Catalyst Na ₂ CO ₃ 0.5g, put into a 500ml four-necked bottle, stir, and raise the temperature not to exceed 40°C for 60 minutes, then start water separation, after water separation, distill off cyclohexane and petroleum ether to obtain 66.9g of methylene , content 98.1%, conversion rate 97.2%.

Take 60g of chloroacetyl chloride and 67g of methylene chloride, add them into a 500ml four-neck flask, stir, keep below 20°C, react for 2 hours, add 100g of absolute ethanol to react for 2 hours, pour NH ₃ to pH=7~9, filter Solid ammonium chloride was obtained, and cyclohexane and petroleum ether were evaporated from the filtrate to obtain 122.1 g of acetochlor with a content of 94.2% and a conversion rate of 93.8%.

Example 5

Get 2-methyl-6-ethylaniline 62g, add petroleum ether and cyclohexane mixed solvent 90g (petroleum ether quality accounts for 30%), 95% ethanol 16g, stabilizer Zn powder 0.5g, paraformaldehyde 28g, catalyst Add 0.5g of triethylamine into a 500ml four-neck bottle, stir, heat up to 55-60°C and react for 40 minutes, then start water separation. After the water separation, distill off cyclohexane and petroleum ether to obtain 67g of methylene, content 98.8%, conversion rate 98.1%.

Take 61g of chloroacetyl chloride and 67g of methylene chloride, add them into a 500ml four-neck flask, stir, keep below 20°C, react for 2 hours, add 180g of absolute ethanol, keep warm at 40°C for 2 hours, and pass in _NH3 until pH=7 ~9, solid ammonium chloride was obtained by filtration, cyclohexane and petroleum ether were evaporated from the filtrate to obtain 119.8 g of acetochlor with a content of 96.2% and a conversion rate of 93.7%.

Comparative Example 1

Take 62g of 2-methyl-6-ethylaniline, add 150g of cyclohexane, 16g of 95% ethanol, 28g of paraformaldehyde, and 0.15g of catalyst sodium hydroxide into a 500ml four-necked bottle, stir, and heat up to 36°C After reacting for 50 minutes, water separation was started. After the water separation, cyclohexane was distilled off to obtain 60 g of methylene, with a content of 98% and a conversion rate of 87.1%.

Take 60g of chloroacetyl chloride and 60g of methylene chloride, add them into a 500ml four-neck flask, stir, keep the temperature below 20°C, react for 2 hours, add 100g of absolute ethanol for 2 hours, and feed NH ₃ until the pH=7～9 Left and right, the solid ammonium chloride was filtered out, and the cyclohexane in the filtrate was distilled off to obtain 101.5 g of acetochlor, with a content of 90.5% and a conversion rate of 83.4%.

Comparative Example 2

Take 62g of 2-methyl-6-ethylaniline, add cyclohexane and petroleum ether, the quality of petroleum ether accounts for 80% (mixed solvent 110g), 16g of 95% ethanol, and a stabilizer (NH4HS) with a molar ratio of 1:1 Add 0.3g of Fe powder, 28g of paraformaldehyde, and 0.5g of tri-n-butylamine into a 500ml four-necked bottle and stir, heat up to 60°C and react for 40 minutes, then start water separation. After the water separation is completed, distill off the solvent to obtain Methylidene 59.3g, content 98%, conversion rate 86.1%.

Take 62g of chloroacetyl chloride and 59.3g of methylene chloride, add them into a 500ml four-neck flask, stir, keep below 20°C, react for 2 hours, add 200g of absolute ethanol to react for 2 hours, and feed _NH3 until the pH is about 7~9 , filtered to obtain solid ammonium chloride, and the filtrate was distilled to remove cyclohexane and petroleum ether to obtain 102.1 g of acetochlor with a content of 90.2% and a conversion rate of 84.6%.

Claims (2)

1. the methene method production technique of an acetochlor is characterized in that this production technique comprises the steps:

(1) under catalyzer and function of stabilizer, make 2-methyl-6-ethylaniline and Paraformaldehyde 96 dehydration reaction in the mixture of non-aromatics solvent hexanaphthene, sherwood oil or hexanaphthene and sherwood oil generate 2-methyl-6-ethyl-N-methylene radical aniline, this product does not need to purify and can carry out next step reaction; Described catalyzer is the mixture of organic bases, mineral alkali or organic bases and mineral alkali, described organic bases is Trimethylamine 99, triethylamine, tri-n-butyl amine, pyridine or N-methylpyrrole, described mineral alkali is an alkali metal hydroxide, alkalimetal oxide or alkaline carbonate; Described stablizer is iron powder, glass putty or zinc powder;

(2) under non-aromatics solvent or condition of no solvent, make the 2-methyl-6-ethyl-N-methylene radical aniline and the chloroacetyl chloride that make carry out acylation reaction, acidylate the reaction of reaction product and dehydrated alcohol then and obtain thick product, separate obtaining acetochlor content at the acetochlor tc more than 93%, the acetochlor transformation efficiency is more than 93%; Wherein the mol ratio of stablizer and 2-methyl-6-ethylaniline is 0.001-0.1: 1; In the production process of 2-methyl-6-ethyl-N-methylene radical aniline, temperature of reaction is 40-100 ℃; In the acylation process of 2-methyl-6-ethyl-N-methylene radical aniline and chloroacetyl chloride, temperature of reaction is 15-120 ℃.

2. according to the methene method production technique of the acetochlor of claim 1, it is characterized in that when the non-aromatics solvent is the mixture of hexanaphthene and sherwood oil, if the sherwood oil quality accounts for below 20% of mixture quality, then the non-aromatics solvent accounts for the 75-90% of total reactant quality; If the sherwood oil quality accounts for the 20-45% of mixture quality, then the non-aromatics solvent accounts for the 60-80% of total reactant quality; If the sherwood oil quality accounts for the 45-80% of mixture quality, then the non-aromatics solvent accounts for the 45-60% of total reactant quality; If the sherwood oil quality accounts for more than 80% of mixture quality, then the non-aromatics solvent accounts for the 35-50% of total reactant quality.