CN116874378A - Preparation method of 4,4' -methylene-bis- (3-chloro-2, 6-diethylaniline) - Google Patents

Abstract

A kind of preparation method of 4,4'-methylene-bis-(3-chloro-2,6-diethylaniline), 4,4'-methylene-bis-(2,6-diethylaniline) Aniline) (MDEA) and inorganic acid are fully stirred to form an amine aqueous solution of MDEA, and after dehydration and drying under vacuum conditions at 85-110°C, dissolve it in a mixture of ionic liquids and organic solvents, and dry at 5-20°C. Chlorine the MDEA by passing chlorine gas under low temperature conditions. After chlorination for 3-6 hours, remove the organic solvent in vacuum. Add alkali to the remaining ionic liquid mixture to neutralize it to pH=7. The mixture is heated to 90-100°C and stirred thoroughly. After 1 hour, the crude M-CDEA and salt-containing ionic liquid aqueous solution were obtained by standing and layering. The crude M-CDEA was purified by alcohol recrystallization to obtain M-CDEA with a purity of more than 98%. The ionic liquid aqueous solution was vacuum distilled at 100-120°C. It can be reused after centrifugal separation and desalination. The process of the invention is simple and easy to implement, and the yield of 4,4’-methylene-bis-(3-chloro-2,6-diethylaniline) is high.

Description

A kind of preparation method of 4,4'-methylene-bis-(3-chloro-2,6-diethylaniline)

Technical field

The invention belongs to the technical field of fine chemicals, and specifically relates to a preparation method of 4,4'-methylene-bis-(3-chloro-2,6-diethylaniline).

Background technique

Polyurethane elastomer is a kind of polymer material with excellent performance. It is generally prepared by chain extender to extend the prepolymer. Commonly used chain extenders mainly include amines and alcohols. Amine chain extenders are generally used together with toluene diethylene. It is used in combination with isocyanate (TDI) prepolymer, and alcohol chain extender is mainly used in combination with diphenylmethane diisocyanate (MDI) prepolymer. At present, the preparation of domestic elastomers is still dominated by TDI prepolymers and amine chain extenders. The most commonly used amine chain extender is 3,3'-dichloro-4,4'-diaminodiphenylmethane. (MOCA), elastomers prepared from MOCA-TDI prepolymers can basically meet the requirements for the physical properties of elastomers in various occasions. However, for some special occasions, such as applications that require products with good dynamic properties, it is necessary to use a High performance amine chain extender M-CDEA.

M-CDEA is a high-performance polyurethane chain extender with a molecular weight of 379g/mol, a melting point of 88-90°C, and a white to light gray powder appearance. The ortho positions of the amino groups in M-CDEA are all replaced by ethyl groups. The Ames test is negative and the safety is good; the electron donating effect of the ethyl group enhances the reactivity of the amino groups, and its reactivity is higher than that of 3,3'-dichloro-4 ,4'-diaminodiphenylmethane (MOCA) is high.

The polyurethane elastomer prepared with M-CDEA as the curing agent has good physical and mechanical properties. It is especially suitable for industrial rollers, paper mill rollers, industrial wheels and industrial tires that operate at high speed during use. It can meet the requirements of good elastomers. Heat resistance, wear resistance and dynamic mechanical properties extend the service life of parts. CN1649925A introduces the reaction of low-free HDI prepolymer with M-CDEA. The storage modulus G' of the prepared elastomer at 200°C is 66-77% of the storage modulus G' at 30°C, and the loss factor tanδ It can still maintain a low value at 30-200℃, and the dynamic mechanical properties are excellent. After analyzing the reason, it is believed that this is mainly due to the increased phase separation of the elastomer when M-CDEA is used as the curing agent, and the soft segment is affected by the hard segment. For smaller reasons.

The production of M-CDEA generally adopts the condensation and rearrangement reaction of 3-chloro-2,6-diethylaniline (CDEA) and formaldehyde under the condition of inorganic acid as catalyst, and then undergoes post-processing such as neutralization, water washing, and drying. It is prepared, as introduced in CN1332932C, by condensation and rearrangement of CDEA and formaldehyde under the action of hydrochloric acid catalyst, and is prepared by post-processing. There are many preparation procedures, and the yield of high-purity M-CDEA is low. The raw material CDEA is generally prepared by ethylene alkylation of m-chloroaniline under high pressure. The process involves the dangerous process of high-pressure alkylation, and there are problems such as difficulty in catalyst recovery and post-processing, and low product yield. With the strengthening of national safety and environmental protection in recent years, most CDEA manufacturers have stopped production, resulting in difficulties in CDEA procurement and the inability to use the original process to produce M-CDEA.

In recent years, various manufacturers have begun to explore new synthesis processes for M-CDEA. For example, CN103288654B discloses a method for preparing M-CDEA by chlorination using MDEA as raw material: first, MDEA is dissolved in acetic acid and reacted with acetic anhydride to generate 4,4 '-Methylenebis(2,6-diethylacetamido)benzene intermediate, dissolve the intermediate 4,4'-methylenebis(2,6-diethylacetamido)benzene in sodium hypochlorite solution Synthesize N-chloro-4,4'-methylenebis(2,6-diethylacetamido)benzene, and then react with acetic acid to obtain 4,4'-methylenebis(3-chloro-2, 6-diethyl)acetamidobenzene intermediate, after reacting the above intermediate with dilute sulfuric acid, adding an alkali solution to the reaction solution, finally obtain 4,4'-methylenebis(3-chloro-2,6- Diethyl)aniline. The steps of this method are complicated and the production efficiency needs to be improved; CN102942491A discloses a method of directly dissolving MDEA in solvents such as methylene chloride, chloroform, dichloroethane, etc., using chlorine as the chlorination reagent for direct chlorination, and decolorizing with activated carbon. , cooling crystallization, filtration and other subsequent processes to prepare M-CDEA. The production process is simple, but when MDEA is directly chlorinated in the above solvent, the amine group is easily oxidized by chlorine and carbonized and turns black, and the yield is low.

Contents of the invention

The object of the present invention is to provide a preparation method of 4,4'-methylene-bis-(3-chloro-2,6-diethylaniline).

In order to achieve the above objects and other related objects, the technical solution provided by the present invention is: a preparation method of 4,4'-methylene-bis-(3-chloro-2,6-diethylaniline), using 4 , 4'-methylene-bis-(2,6-diethylaniline) and chlorine are used as raw materials, and chlorine is used as the chlorination reagent at 5-20°C to 4,4'-methylene-bis. -(2,6-diethylaniline) undergoes chlorination reaction to obtain 4,4'-methylene-bis-(3-chloro-2,6-diethylaniline).

The preferred technical solution is: before reacting 4,4'-methylene-bis-(2,6-diethylaniline) and chlorine, 4,4'-methylene-bis-(2,6-diethylaniline) aniline) reacts with inorganic acid to form the amine salt of 4,4'-methylene-bis-(2,6-diethylaniline).

The preferred technical solution is: the inorganic acid is at least one of hydrochloric acid, sulfuric acid, and phosphoric acid; when hydrochloric acid is selected, the mass fraction of hydrochloric acid is 35%-37%, and the molar ratio of amine groups to hydrochloric acid is 1:1. -1:1.05.

The preferred technical solution is: the amine salt of 4,4'-methylene-bis-(2,6-diethylaniline) needs to remove water before reacting with chlorine. The process conditions are: vacuum drying to remove water, The temperature is 85-110℃, and the vacuum degree is 0.08-0.1MPa.

The preferred technical solution is: dry amine salt is dissolved in a mixture composed of ionic liquid and organic solvent. The ionic liquid is 1-hexyl-3-methylimidazole chloride and 1-octyl-3-methylimidazole chloride. , at least one of 1-butyl-3-methylimidazole chloride, 1-allyl-3-methylimidazole chloride and N-butylpyridine chloride, the organic solvent is carbon tetrachloride, chloroform , at least one of 1,2-dichloroethane.

The preferred technical solution is: the ionic liquid is at least one of 1-hexyl-3-methylimidazole chloride and 1-octyl-3-methylimidazole chloride, and the organic solvent is 1,2-dichloroethane. ; The ionic liquid and the organic solvent are vacuum dehydrated before use, and the moisture content is controlled to be less than or equal to 0.1%; and the mass ratio of the ionic liquid to the organic solvent is 20:80-80:20.

The preferred technical solution is: the mass ratio of the amine salt to the mixture is 1:5-1:20.

The preferred technical solution is: the chlorination reaction is carried out in a closed reaction kettle, the pressure of the kettle is maintained at 0-0.1MPa, and the chlorination time is 3-6 hours.

The preferred technical solution is: after the chlorination reaction is completed, distill and recover the organic solvent; add an alkali solution to the reaction solution after removing the solvent to neutralize the acid, stir and neutralize until the aqueous solution becomes neutral, and maintain the temperature at 90-100°C. The water phase is left to stratify under the conditions: the aqueous phase is an ionic liquid aqueous solution. The aqueous phase is dehydrated in a vacuum and centrifuged to remove salts, and then the ionic liquid is reused. After the organic phase is cooled, it is 4,4'-methylene-bis-(3 -Chloro-2,6-diethylaniline) crude product, after recrystallization and purification, a high-purity target product is obtained; the alkali in the alkali solution is at least one of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, and ammonia water. kind.

The preferred technical solution is: after the crude product of 4,4'-methylene-bis-(3-chloro-2,6-diethylaniline) is purified by recrystallization, 4,4'-methylene with a purity of more than 98% is obtained. Methyl-bis-(3-chloro-2,6-diethylaniline), the recrystallization solvent includes methanol, ethanol, isobutanol or a mixture of alcohol and water; the mass ratio of crude product to recrystallization solvent is 1:5 -1:10.

Due to the application of the above technical solutions, the present invention has the following advantages compared with the prior art:

The process of the invention is simple and easy to implement, and the yield of 4,4'-methylene-bis-(3-chloro-2,6-diethylaniline) is high.

Detailed ways

The implementation of the present invention is described below with specific embodiments. Those familiar with this technology can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

Example 1: A preparation method of 4,4’-methylene-bis-(3-chloro-2,6-diethylaniline)

Weigh 400g of 1-hexyl-3-methylimidazole chloride and 600g of dichloroethane after drying and removing water respectively, and add them to a 2L stainless steel high-pressure reaction kettle. Add 128g of dried MDEA hydrochloride and nitrogen. Replace 3 times, turn on the low-temperature cooling circulation pump to lower the temperature in the reactor to 10°C and stir thoroughly to completely dissolve the amine salt, then introduce 48.6g of chlorine gas into the reactor, adjust the cooling cycle to control the temperature in the reactor to not exceed 15°C , the pressure is not greater than 0.05MPa. After the chlorine is passed, the pressure is maintained so that the pressure is close to normal pressure after the reaction. After 3.5 hours of reaction, the reaction liquid is transferred to the vacuum distillation device, heated to 50℃-60℃, distilled and cooled to recover the organic solvent. 1,2-Dichloroethane, the uncondensed gas is passed into an aqueous solution of sodium hydroxide for absorption.

Add 350 ml of 1 mol/L sodium carbonate solution to the reaction kettle after distillation, stir thoroughly and raise the temperature to 93°C, let it stand for 30 minutes at 93-95°C, and recover the organic phase and aqueous phase respectively after the liquid is separated. After the phase is dehydrated and dried under conditions of 100-120°C and vacuum degree of 0.08-0.1MPa, and the salts generated during neutralization are separated by centrifugation, an ionic liquid that can be reused is obtained; after cooling the organic phase, crude product M-CDEA 122.5g is obtained. According to liquid chromatography detection, its purity is 94.3%, of which unreacted raw material MDEA is 0.3%, monochlorinated MDEA is 2.8%, and trichlorinated MDEA is 2.6%;

Add 600g of isopropyl alcohol to 100g of crude M-CDEA and boil, then cool and recrystallize twice to obtain M-CDEA with a purity of 98.8% (HPLC).

Example 2: A preparation method of 4,4’-methylene-bis-(3-chloro-2,6-diethylaniline)

The experimental operation is the same as Experiment 1, in which the ionic liquid and dichloroethane are recycled materials from Experiment 1. The experimental results are as follows: the purity of crude M-CDEA is 93.9%, of which the unreacted raw material MDEA is 0.4%, and the monochlorinated MDEA is 2.7%, trichlorinated MDEA is 3%.

Example 3: A preparation method of 4,4’-methylene-bis-(3-chloro-2,6-diethylaniline)

The experimental operation is the same as Experiment 1, in which the ionic liquid and dichloroethane are recycled materials from Experiment 2. The experimental results are as follows: the purity of crude M-CDEA is 93.7%, of which unreacted raw material MDEA is 0.4%, and monochlorinated MDEA is 3.1%, trichlorinated MDEA is 2.8%.

Example 4: A preparation method of 4,4’-methylene-bis-(3-chloro-2,6-diethylaniline)

The experimental operation is the same as Experiment 1, in which the mass of ionic liquid 1-octyl-3-methylimidazole chloride is 600g, the mass of dichloroethane is 400g, the chlorination time is 3h, and the post-processing operating conditions remain unchanged. The experimental results are as follows : The purity of crude M-CDEA is 94.6%, of which unreacted raw material MDEA is 0.3%, monochlorinated MDEA is 2.4%, and trichlorinated MDEA is 2.7%.

Summary table of chlorination reaction results

It can be seen from the experimental results that when the mixture of ionic liquid 1-hexyl-3-methylimidazole chloride, 1-octyl-3-methylimidazole chloride and dichloroethane is used as the solvent for the MDEA chlorination reaction, good results can be obtained. The ionic liquid is both a solvent and a catalyst for the chlorination reaction; the ionic liquid and dichloroethane can be reused after separation, and the chlorination effect is not significantly affected.

Example 5: A preparation method of 4,4’-methylene-bis-(3-chloro-2,6-diethylaniline)

Using MDEA as raw material, after the amine group is protected by acid, chlorine gas is used as the chlorination reagent to chlorinate the amine salt of MDEA, and then neutralization, recrystallization and other post-processing processes are used to prepare high-purity M-CDEA. This method has the advantages of high chlorination efficiency and simple post-treatment.

The reaction that occurs when hydrochloric acid is used as the amine protecting agent is as follows:

Main reaction:

Side reaction 1:

Side reaction 2:

1. This method uses MDEA and chlorine as raw materials, and chlorine is used as a chlorination reagent to chlorinate MDEA under low temperature conditions. Chlorine has strong oxidizing properties. In order to prevent the amine group in MDEA from being oxidized by chlorine, before reacting with chlorine, MDEA is reacted with an inorganic acid to form the amine salt of MDEA. The inorganic acids that can be used include hydrochloric acid, sulfuric acid, phosphoric acid, etc., with the preferred quality The fraction is 35% hydrochloric acid aqueous solution. In order to fully react between the amine group and the acid to form an amine salt, the molar ratio of the amine group to hydrochloric acid is 1:1.

2. When chlorine gas comes into contact with water, it will generate an aqueous solution of hydrogen chloride and hypochlorous acid. The generation of hydrochloric acid and hypochlorous acid consumes chlorine gas, so that chlorine gas can no longer undergo an electrophilic substitution reaction with the hydrogen on the benzene ring, that is, in the reaction system The presence of water will make the target reaction - chlorination reaction impossible, so the chlorination reaction must be carried out under anhydrous conditions. The amine salt formed by MDEA and hydrochloric acid needs to be dried to remove water. The conditions for water removal are a temperature of 85°C and a vacuum of 0.08MPa. At the same time, the chlorination reaction needs to be carried out in a certain solvent, and the moisture content of the chlorination solvent needs to be controlled. At <0.1%, if the moisture content of the solvent does not meet the standard before use, it must be vacuum-drained before use.

3. The chlorination reaction needs to be carried out in a certain solvent, and the solvent needs to have good solubility for MDEA hydrochloride and chlorine gas at the same time, so as to promote full contact with MDEA hydrochloride and chlorine gas. Solvents that can be used include ionic liquids and organic solvents. Ionic liquids have good solubility in both organic and inorganic substances, and have stable physical and chemical properties. This reaction is a chlorination reaction. The available ionic liquids use chloride ions as anions. The ionic liquids can absorb chlorine gas and combine with chlorine gas to form stable trichloride ion ionic liquids. While increasing the concentration of chlorine in the solvent, they can also Act as a catalyst to promote the chlorination reaction. Optional ionic liquids include 1-hexyl-3-methylimidazole chloride, 1-octyl-3-methylimidazole chloride, and 1-butyl-chloride. 3-methylimidazole, 1-allyl-3-methylimidazole chloride, N-butylpyridine chloride, etc. Commonly used chlorinated organic solvents include carbon tetrachloride, chloroform, 1,2-dichloroethane, etc. 1-hexyl-3-methylimidazole chloride and 1-octyl-3-methylimidazole chloride are preferred, and 1,2-dichloroethane is preferred as the organic solvent.

4. The solvent used in the present invention is a mixture of ionic liquid and organic solvent. The preferred mass ratio of ionic liquid to 1,2-dichloroethane is 20:80.

5. In order to ensure that the amine salt is fully dissolved in the mixed solvent, the mass ratio of the amine salt to the mixed solvent is 1:5-1:20. Continuing to increase the amount of solvent will not significantly promote the chlorination reaction and increase production. In terms of cost and comprehensive consideration, the mass ratio of amine salt to mixed solvent is preferably 1:5.

6. The chlorination reaction can be carried out in an open container, such as a commonly used chlorination reaction kettle, tower, etc. The chlorine gas is introduced into the reaction solution and then discharged and collected through the outlet; it can also be carried out in a closed container such as a high-pressure reaction kettle. When carried out in a closed reaction kettle, the amount of chlorine gas introduced is small, and its good sealing can also make the chlorination reaction safer. The present invention prefers a closed reaction kettle, keeping the kettle temperature at 5°C and the kettle pressure. 0MPa, chlorination time 3h.

7. After the chlorination reaction is completed, distill and recover the organic solvent, incompletely reacted chlorine, and hydrogen chloride generated by the chlorination reaction. After removing the solvent, continue to add alkali to the reaction solution to neutralize the hydrochloric acid added to protect the amine group, and stir to neutralize. Until the aqueous solution becomes neutral, available bases include: sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, ammonia, etc. Keep the temperature at 90°C and let it stand for layering to obtain the organic phase and the aqueous phase respectively. After the phase is cooled, the crude product of M-CDEA with a purity of about 93% is obtained, and the aqueous phase is an ionic liquid aqueous solution.

8. Alcohol or alcohol/water mixture can be used as solvent to recrystallize and purify crude M-CDEA. The mass ratio of crude M-CDEA to solvent is 1:5, and finally obtain M-CDEA with a purity of more than 98%; ionic liquid aqueous solution After removing water in a vacuum and centrifuging the ionic liquid to remove salt, the ionic liquid can be reused.

Example 6: A preparation method of 4,4’-methylene-bis-(3-chloro-2,6-diethylaniline)

A method for preparing high-performance polyurethane chain extender 4,4’-methylene-bis-(3-chloro-2,6-diethylaniline) (M-CDEA). M-CDEA is prepared by using 4,4’-methylene-bis-(2,6-diethylaniline) (MDEA) and chlorine as the raw material. MDEA is chlorinated using chlorine as the chlorination reagent at low temperature.

Before the reaction between MDEA and chlorine, MDEA reacts with an inorganic acid to form an amine salt of MDEA to prevent the amine group from being oxidized during chlorination. The inorganic acid that can be used includes sulfuric acid, and the molar ratio of the amine group to sulfuric acid is 1:1.05.

The amine salt of MDEA needs to remove water before reacting with chlorine. The vacuum drying temperature for water removal is 110°C and the vacuum degree is 0.1MPa.

The vacuum-dried amine salt is dissolved in a mixture of ionic liquid and organic solvent. The ionic liquid is 1-hexyl-3-methylimidazole chloride and 1-octyl-3-methylimidazole chloride in a volume ratio of 1:1. The organic solvent is a mixture of carbon tetrachloride and chloroform in a volume ratio of 1:1.

The ionic liquid and the organic solvent are vacuum dehydrated before use, and the moisture content is controlled to be less than 0.1%; and the mass ratio of the ionic liquid to the organic solvent is 80:20.

The amine salt is dissolved in a mixture of ionic liquid and organic solvent, and the mass ratio of amine salt to mixed solvent is 1:10.

The chlorination reaction is carried out in a closed reaction kettle, the chlorination temperature is 20°C, the kettle pressure is maintained at 0.1MPa, and the chlorination time is 6 hours.

After the chlorination reaction is completed, distill and recover the organic solvent; add an alkali solution to the reaction solution after removing the solvent to neutralize the acid, and stir and neutralize until the aqueous solution becomes neutral. The available alkali is sodium carbonate and potassium carbonate in a ratio of 1:1. The mixture composed of mass ratios is left to stratify at a temperature of 100°C: the water phase is an ionic liquid aqueous solution, and the ionic liquid can be reused after the aqueous phase is vacuum dehydrated and centrifuged to remove salt; the organic phase is cooled and The crude M-CDEA product can be purified by recrystallization to obtain a high-purity target product.

After the crude M-CDEA is purified by recrystallization, M-CDEA with a purity of more than 98% can be obtained. The recrystallization solvent includes methanol, and the mass ratio of the crude product to the recrystallization solvent is 1:10.

The above is only used to explain the preferred embodiments of the present invention, and is not intended to limit the present invention in any form. Therefore, any modifications or changes related to the present invention are made under the same spirit of the invention. , should still be included in the scope of protection intended by the present invention.

Claims (10)

1. A preparation method of 4,4' -methylene-bis- (3-chloro-2, 6-diethylaniline) is characterized by comprising the following steps: 4,4' -methylene-bis- (2, 6-diethylaniline) and chlorine are taken as raw materials, and the chlorine is taken as a chlorinating agent to carry out chlorination reaction on the 4,4' -methylene-bis- (2, 6-diethylaniline) at the temperature of 5-20 ℃ to prepare the 4,4' -methylene-bis- (3-chlorine-2, 6-diethylaniline).

2. The method for producing 4,4' -methylene-bis- (3-chloro-2, 6-diethylaniline) according to claim 1, wherein: before reacting 4,4' -methylene-bis- (2, 6-diethylaniline) with chlorine, 4' -methylene-bis- (2, 6-diethylaniline) is reacted with a mineral acid to form the amine salt of 4,4' -methylene-bis- (2, 6-diethylaniline).

3. The method for producing 4,4' -methylene-bis- (3-chloro-2, 6-diethylaniline) according to claim 2, wherein: the inorganic acid is at least one of hydrochloric acid, sulfuric acid and phosphoric acid; when hydrochloric acid is selected, the mass fraction of the hydrochloric acid is 35% -37%, and the molar ratio of the amino groups to the hydrochloric acid is 1:1-1:1.05.

4. The method for producing 4,4' -methylene-bis- (3-chloro-2, 6-diethylaniline) according to claim 2, wherein: the amine salt of 4,4' -methylene-bis- (2, 6-diethylaniline) needs to be dehydrated before reacting with chlorine, and the process conditions are as follows: vacuum drying and dewatering at 85-110deg.C and vacuum degree of 0.08-0.1MPa.

5. The method for producing 4,4' -methylene-bis- (3-chloro-2, 6-diethylaniline) according to claim 4, wherein: the dried amine salt is dissolved in a mixture composed of ionic liquid and organic solvent, wherein the ionic liquid is at least one of chloridized 1-hexyl-3-methylimidazole, chloridized 1-octyl-3-methylimidazole, chloridized 1-butyl-3-methylimidazole, chloridized 1-allyl-3-methylimidazole and chloridized N-butylpyridine, and the organic solvent is at least one of carbon tetrachloride, chloroform and 1, 2-dichloroethane.

6. The method for producing 4,4' -methylene-bis- (3-chloro-2, 6-diethylaniline) according to claim 5, wherein: the ionic liquid is at least one of 1-hexyl-3-methylimidazole chloride and 1-octyl-3-methylimidazole chloride, and the organic solvent is 1, 2-dichloroethane; the ionic liquid and the organic solvent are dehydrated in vacuum before use, and the water content is controlled to be less than or equal to 0.1 percent; and the mass ratio of the ionic liquid to the organic solvent is 20:80-80:20.

7. The method for producing 4,4' -methylene-bis- (3-chloro-2, 6-diethylaniline) according to claim 5, wherein: the mass ratio of the amine salt to the mixture is 1:5-1:20.

8. The method for producing 4,4' -methylene-bis- (3-chloro-2, 6-diethylaniline) according to claim 1, wherein: the chlorination reaction is carried out in a closed reaction kettle, the kettle pressure is kept at 0-0.1MPa, and the chlorination time is 3-6h.

9. The method for producing 4,4' -methylene-bis- (3-chloro-2, 6-diethylaniline) according to claim 1, wherein: after the chlorination reaction is finished, distilling and recycling the organic solvent; adding an alkali solution to the reaction solution after the solvent removal to neutralize the acid, stirring and neutralizing until the aqueous solution is neutral, and standing and layering under the condition of keeping the temperature at 90-100 ℃: the water phase is an ionic liquid water solution, and the ionic liquid is recycled after the water phase is dehydrated in vacuum and is subjected to centrifugal separation for desalting; the organic phase is cooled to obtain a crude product of 4,4' -methylene-bis- (3-chloro-2, 6-diethylaniline), and the crude product is recrystallized and purified to obtain a high-purity target product; the alkali in the alkali solution is at least one of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate and ammonia water.

10. The method for producing 4,4' -methylene-bis- (3-chloro-2, 6-diethylaniline) according to claim 9, wherein: the 4,4 '-methylene-bis- (3-chloro-2, 6-diethylaniline) crude product is recrystallized and purified to obtain 4,4' -methylene-bis- (3-chloro-2, 6-diethylaniline) with the purity of more than 98 percent, and the recrystallization solvent comprises methanol, ethanol, isobutanol or a mixture of alcohol and water; the mass ratio of the crude product to the recrystallization solvent is 1:5-1:10.