A method for low-temperature preparation of tetramethylethylenediamine

Abstract

The application discloses a method for preparing tetramethylethylenediamine in a low-temperature environment and belongs to the field of organic chemical synthesis. The method comprises the following steps: methanol is placed in a reaction kettle, a diamine compound is added into the reaction kettle and is stirred and mixed, after the diamine compound is completely added, a manganese ion modified catalyst is added into the reaction kettle and is mixed with the methanol and the diamine compound, after the manganese ion modified catalyst is completely added, the reaction kettle is replaced with an inert gas, after the replacement is completed, the reaction kettle is subjected to a warming reaction to obtain a reaction liquid, the reaction liquid is filtered to collect a filtrate, and the filtrate is subjected to distillation and rectification in sequence to obtain tetramethylethylenediamine. The modified manganese ion catalyst with high activity is constructed, and the low-temperature catalytic reaction is realized under the condition that hydrogen is not introduced, by using the proton hydrogen of the alcohol itself, and the method is safe and effective.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of organic chemical synthesis, and particularly relates to a method for preparing tetramethylethylenediamine in a low-temperature environment. BACKGROUND

[0002] Tetramethylethylenediamine, abbreviated as TMEDA, is a special tertiary amine organic substance, which appears colorless and transparent, with a slight ammonia smell, and can be mutually soluble with water, ethanol, ether and other solvents. Tetramethylethylenediamine is an important organic synthetic material, which has important applications in the fields of medicine, dye intermediates, pesticides, etc. For example, it is used as an emulsifier and preservative in the food and cosmetic industries, as a lubricant, pigment and antifreeze in plastic products, and as a biochemical reagent, epoxy resin crosslinking agent and intermediate for preparing quaternary ammonium compounds in chemical production.

[0003] The existing synthesis methods of tetramethylethylenediamine mainly include the following: Patent CN1962606A discloses a method for synthesizing tetramethylethylenediamine by using a pipeline reactor. The invention uses 1,2-dichloroethane, sodium hydroxide and dimethylamine as raw materials to synthesize tetramethylethylenediamine in a pipeline reactor. The principle of this method is to use the substitution reaction of halogenated alkyl and amine group. A large amount of hydrochloric acid product is generated in the reaction, which needs to be neutralized with a large amount of alkali. Although tetramethylethylenediamine can be finally prepared, a large amount of inorganic salt wastewater is generated, and the treatment cost of the wastewater is too high. In view of the problem of inorganic salt wastewater in this method, amine hydrogenation and methylation hydrogenation preparation methods are developed. Patent CN104557562A discloses a method for directly catalyzing amination of dimethylethanolamine to produce tetramethylethylenediamine. The invention uses dimethylethanolamine and dimethylamine as raw materials, and under the condition of a self-made catalyst, amination is carried out at 100-250℃, and hydrogen is introduced for hydrogenation to obtain the target product. Patent CN110317138B discloses a preparation method of tetramethylethylenediamine. The invention uses polyformaldehyde and ethylenediamine as raw materials, and under the catalysis of a catalyst, hydrogen is introduced for methylation hydrogenation reaction at high temperature (120-130℃) and high pressure (2.8-3.2 MPa) to prepare the target product. Both amine hydrogenation and methylation hydrogenation are carried out at high temperature, which has high production cost. Moreover, the use of hydrogen for hydrogenation reduction has the following problems: hydrogen is a flammable gas, which can easily mix with air to become an explosive mixture. Moreover, hydrogenation reaction is a high-temperature exothermic reaction. Hydrogen can corrode the reaction container (hydrogen embrittlement phenomenon) under high temperature and high pressure, thereby greatly reducing the service life of the equipment. Moreover, the corroded equipment is prone to hydrogen leakage, which further increases the risk of hydrogen explosion.

[0004] Therefore, it is of practical production significance to design a method for preparing tetramethylethylenediamine at low temperature and avoiding the use of hydrogen to corrode the equipment and cause leakage. SUMMARY

[0005] In view of the deficiencies in the prior art, the present application uses diamine compounds and methanol as raw materials, and through a self-made catalyst, methanol is oxidized by hydrogen abstraction at low temperature to form aldehydes with high reactivity, then the diamine compounds react with the aldehydes to form compounds with imine structure, and the catalyst after hydrogen abstraction catalyzes the hydrogenation reduction of the compounds with imine structure to prepare tetramethyl ethylenediamine, so as to solve the problems raised in the background art. Specifically, the technical scheme of the present application includes the following contents:

[0006] A method for preparing tetramethyl ethylenediamine at low temperature, the method comprising the following steps:

[0007] Methanol is placed in a reaction kettle, and a diamine compound is added to the reaction kettle and stirred and mixed;

[0008] After the diamine compound is added, a manganese ion modified catalyst is added to the reaction kettle and mixed with the methanol and the diamine compound;

[0009] After the manganese ion modified catalyst is added, the reaction kettle is replaced with an inert gas, and after the replacement is completed, the reaction kettle is heated to obtain a reaction liquid;

[0010] The reaction liquid is filtered to collect a filtrate, and the filtrate is treated by distillation and rectification in sequence to obtain tetramethyl ethylenediamine.

[0011] Further, the diamine compound includes N,N'-dimethylethylenediamine, N,N-dimethylethylenediamine or ethylenediamine, preferably N,N-dimethylethylenediamine.

[0012] Further, the molar ratio of the methanol to the diamine compound is 2-4:1.

[0013] Further, the temperature when the diamine compound is added to the reaction kettle is 0-50℃.

[0014] Further, the amount of the manganese ion modified catalyst is 1%-5% of the total mass of the methanol and the diamine compound.

[0015] Further, the preparation method of the manganese ion modified catalyst comprises the following steps:

[0016] The metal manganese ion, the ligand compound and dimethylformamide are mixed, then after ultrasonic treatment, the mixture is reacted at 70-90 DEG C for 30-60 min, then the crystal is precipitated after cooling, the crystal is vacuum dried to obtain a solid, the solid is calcined to obtain the manganese ion modified catalyst, the ultrasonic treatment is carried out at 100-140 W for 10-30 min, the vacuum drying is carried out at 140-160 DEG C, and the calcination is carried out at 400-500 DEG C.

[0017] Further, the metal manganese ion includes manganese chloride, manganese nitrate or manganese carbonate.

[0018] Further, the ligand compound includes acetylacetone, ethylenediaminetetraacetic acid or trifluoroacetyl trifluoromethanesulfonate, preferably trifluoroacetyl trifluoromethanesulfonate.

[0019] Further, the mass ratio of the metal manganese ion to the ligand compound is 1:1-5.

[0020] Further, the inert gas includes nitrogen, helium or argon.

[0021] Further, after the inert gas is used to replace the reaction kettle, the oxygen content in the reaction kettle is ≤0.2%.

[0022] Further, the temperature for the reaction kettle to react is 60-90 DEG C.

[0023] Further, the distillation temperature is 63-67 DEG C, the rectification includes rectification at 100-110 DEG C to remove water and rectification at 115 DEG C-130 DEG C to collect tetramethylethylenediamine.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] (1) The present application uses the multi-electron donating effect of the ligand compound with multi-electron donating groups to combine with the manganese ion, and cooperatively improves the stability and catalytic activity of the manganese ion catalyst, so that the catalytic reaction at low temperature is realized.

[0026] (2) Because of the low reactivity of methanol, it is difficult to react with diamine compounds. The high-activity manganese ion modified catalyst oxidizes methanol by dehydrogenation to form formaldehyde with high reactivity, and then the diamine compound attacks the formaldehyde to form an imine structure compound, and then the hydrogenation reduction is carried out under the catalysis of the modified manganese ion catalyst combined with hydrogen atoms to obtain tetramethyl ethylenediamine, so that the proton hydrogen in methanol is used as a hydrogen source, and no additional hydrogen is introduced for reaction, thereby avoiding the hydrogen embrittlement phenomenon caused by hydrogen under high temperature and the adverse effects of leakage and explosion caused by improper operation, and the excess formaldehyde can also be regenerated to methanol under the catalysis of the modified manganese ion catalyst combined with hydrogen atoms, and then recycled.

[0027] (3) The present application adopts a one-pot method of dehydrogenation-amination condensation-hydrogenation, and the only by-product is water, which has low pollution and high atom economy. DETAILED DESCRIPTION

[0028] The technical solutions of the present application will be clearly and completely described below through the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0029] Unless otherwise specified, the raw materials and reagents used in the present application are commercially available or can be prepared by known methods.

[0030] The relevant reagents and raw materials information is as follows:

[0031] Reaction raw materials: N,N'-dimethylethylenediamine (88, ml), N,N-dimethylethylenediamine (88, ml), ethylenediamine (60, ml) and methanol (32, ml) are purchased from Shanghai Aldrin Reagent Co., Ltd.

[0032] Modified manganese ion catalyst synthesis raw materials: manganese chloride (126, g), manganese nitrate (179, g), manganese carbonate (115, g), acetylacetone (100, ml), ethylenediaminetetraacetic acid (292, g) and trifluoroacetyl triflate (246, g) are purchased from Shanghai Aldrin Reagent Co., Ltd.

[0033] Phenylethanol and N,N'-dibenzoylhydrazine are purchased from Shanghai Aldrin Reagent Co., Ltd.

[0034] Preparation Example 1:

[0035] The preparation of the modified manganese ion catalyst specifically includes the following steps:

[0036] Take 2g of manganese chloride and 2g of acetylacetone into a reactor, add 20ml of dimethylformamide for mixing and stirring until the solid is completely dissolved, place the reactor containing manganese chloride and acetylacetone in an ultrasonic cleaner, control the power of the ultrasonic cleaner to 100W, ultrasonic for 30min, then place the reactor in a 70℃ water bath for 60min, cool to crystallization, wash the crystals with dimethylformamide solution, then place the crystals in a vacuum drying oven at 140℃ for 1h, then place the dried crystals in a muffle furnace, start timing when the temperature of the muffle furnace rises to 400℃, calcine for 2h, and then naturally cool to obtain the modified manganese ion catalyst.

[0037] Preparation Example 2:

[0038] The preparation of the modified manganese ion catalyst specifically includes the following steps:

[0039] Take 2g of manganese chloride and 4g of acetylacetone into a reactor, add 30ml of dimethylformamide for mixing and stirring until the solid is completely dissolved, place the reactor containing manganese chloride and acetylacetone in an ultrasonic cleaner, control the power of the ultrasonic cleaner to 120W, ultrasonic for 20min, then place the reactor in a 80℃ water bath for 50min, cool to crystallization, wash the crystals with dimethylformamide solution, then place the crystals in a vacuum drying oven at 150℃ for 1h, then place the dried crystals in a muffle furnace, start timing when the temperature of the muffle furnace rises to 450℃, calcine for 2h, and then naturally cool to obtain the modified manganese ion catalyst.

[0040] Preparation Example 3:

[0041] The preparation of the modified manganese ion catalyst specifically includes the following steps:

[0042] Take 2g of manganese chloride and 6g of acetylacetone into a reactor, add 40ml of dimethylformamide for mixing and stirring until the solid is completely dissolved, place the reactor containing manganese chloride and acetylacetone in an ultrasonic cleaner, control the power of the ultrasonic cleaner to 130W, ultrasonic for 10min, then place the reactor in a 90℃ water bath for 30min, cool to crystallization, wash the crystals with dimethylformamide solution, then place the crystals in a vacuum drying oven at 160℃ for 1h, then place the dried crystals in a muffle furnace, start timing when the temperature of the muffle furnace rises to 500℃, calcine for 2h, and then naturally cool to obtain the modified manganese ion catalyst.

[0043] Preparation Example 4:

[0044] The preparation of the modified manganese ion catalyst specifically includes the following steps:

[0045] Take 2 g of manganese chloride and 10 g of acetylacetone into a reactor, add 60 ml of dimethylformamide for mixing and stirring until the solid is completely dissolved, place the reactor containing manganese chloride and acetylacetone in an ultrasonic cleaner, control the power of the ultrasonic cleaner to 140 W, ultrasonic for 10 min, then place the reactor in a 90℃ water bath for 30 min, cool to completely precipitate the crystals, wash the crystals with dimethylformamide solution, then place the crystals in a vacuum drying oven at 160℃ for 1 h, then place the dried crystals in a muffle furnace, start timing when the temperature of the muffle furnace rises to 500℃, calcine for 2 h, and then naturally cool to obtain the modified manganese ion catalyst.

[0046] Preparation Example 5:

[0047] The preparation of the modified manganese ion catalyst specifically includes the following steps:

[0048] Different from Preparation Example 4, manganese chloride is replaced by manganese nitrate and acetylacetone is replaced by ethylenediaminetetraacetic acid, and the rest of the conditions remain unchanged to obtain the modified manganese ion catalyst.

[0049] Preparation Example 6:

[0050] The preparation of the modified manganese ion catalyst specifically includes the following steps:

[0051] Different from Preparation Example 4, manganese chloride is replaced by manganese nitrate and acetylacetone is replaced by trifluoroacetyl triflate, and the rest of the conditions remain unchanged to obtain the modified manganese ion catalyst.

[0052] Preparation Example 7:

[0053] The preparation of the modified manganese ion catalyst specifically includes the following steps:

[0054] Different from Preparation Example 4, manganese chloride is replaced by manganese carbonate and acetylacetone is replaced by trifluoroacetyl triflate, and the rest of the conditions remain unchanged to obtain the modified manganese ion catalyst.

[0055] Example 1:

[0056] A method for preparing tetramethyl ethylenediamine at low temperature, specifically including the following steps:

[0057] Take 0.1 mol of methanol into the reaction kettle, control the temperature of the reaction kettle at 0°C, take 0.05 mol of N,N'-dimethylethylenediamine into the reaction kettle and stir with methanol, after the addition of N,N'-dimethylethylenediamine is completed, take 76 mg of modified manganese ion catalyst in preparation example 1 into the reaction kettle and mix with N,N'-dimethylethylenediamine and methanol, close the kettle cover, replace the air in the kettle with nitrogen, detect the oxygen content in the kettle as 0.2%, stop the replacement, and start timing when the reaction kettle is heated to 60°C. After 4h of reaction, the reaction liquid in the reaction kettle is filtered to collect the filtrate. The filtrate is first subjected to a 63°C distillation kettle to recover methanol. After recovery is completed, the reaction liquid is transferred to a rectification tower. After removing the byproduct water at 100°C, the temperature is increased to 115°C to collect tetramethylethylenediamine. The obtained tetramethylethylenediamine is detected, and the yield is 92.04% and the purity is 97.25%.

[0058] Example 2:

[0059] A method for low-temperature preparation of tetramethylethylenediamine, specifically comprising the following steps:

[0060] Different from example 1, the modified manganese ion catalyst in preparation example 1 is replaced with the modified manganese ion catalyst in preparation example 2, and the rest of the conditions remain unchanged. The yield of tetramethylethylenediamine is measured as 92.21%, and the purity is 97.29%.

[0061] Example 3:

[0062] A method for low-temperature preparation of tetramethylethylenediamine, specifically comprising the following steps:

[0063] Different from example 1, the modified manganese ion catalyst in preparation example 1 is replaced with the modified manganese ion catalyst in preparation example 3, and the rest of the conditions remain unchanged. The yield of tetramethylethylenediamine is measured as 92.28%, and the purity is 97.42%.

[0064] Example 4:

[0065] A method for low-temperature preparation of tetramethylethylenediamine, specifically comprising the following steps:

[0066] Different from example 1, the modified manganese ion catalyst in preparation example 1 is replaced with the modified manganese ion catalyst in preparation example 4, and the rest of the conditions remain unchanged. The yield of tetramethylethylenediamine is measured as 92.45%, and the purity is 97.76%.

[0067] Example 5:

[0068] A method for low-temperature preparation of tetramethylethylenediamine, specifically comprising the following steps:

[0069] The modified manganese ion catalyst in Preparation Example 1 was replaced with the modified manganese ion catalyst in Preparation Example 5, and the yield of tetramethylethylenediamine was 92.68% and the purity was 98.56% under the same conditions as in Example 1.

[0070] Example 6

[0071] A method for preparing tetramethylethylenediamine at low temperature, specifically comprising the following steps:

[0072] The modified manganese ion catalyst in Preparation Example 1 was replaced with the modified manganese ion catalyst in Preparation Example 6, and the yield of tetramethylethylenediamine was 92.85% and the purity was 98.69% under the same conditions as in Example 1.

[0073] Example 7

[0074] A method for preparing tetramethylethylenediamine at low temperature, specifically comprising the following steps:

[0075] 0.15 mol of methanol was weighed into a reaction kettle, the temperature of the reaction kettle was controlled at 10°C, 0.05 mol of N,N-dimethylethylenediamine was weighed into the reaction kettle and stirred with the methanol, after the addition of N,N-dimethylethylenediamine was completed, 184 mg of the modified manganese ion catalyst in Preparation Example 6 was weighed into the reaction kettle and mixed with the N,N-dimethylethylenediamine and methanol, the kettle cover was closed, the air in the kettle was replaced with helium, the oxygen content in the kettle was detected to be 0%, and the replacement was stopped. The reaction kettle was heated to 70°C, and the timing started. After 4 h of reaction, the reaction liquid in the reaction kettle was filtered to collect the filtrate. The filtrate was first passed through a 65°C distillation kettle to recover the methanol. After the recovery was completed, the reaction liquid was transferred to a rectification tower. After removing the byproduct water at 105°C, the temperature was increased to 120°C to collect tetramethylethylenediamine. The obtained tetramethylethylenediamine was detected, and the yield was 93.18% and the purity was 98.87%.

[0076] Example 8

[0077] A method for preparing tetramethylethylenediamine at low temperature, specifically comprising the following steps:

[0078] Take 0.2 mol of methanol into the reaction kettle, control the temperature of the reaction kettle at 30℃, take 0.05 mol of ethylenediamine into the reaction kettle and mix with methanol, after the addition of ethylenediamine is completed, take 282 mg of modified manganese ion catalyst in preparation example 6 into the reaction kettle and mix with ethylenediamine and methanol, close the kettle cover, replace the air in the kettle with nitrogen, detect the oxygen content in the kettle as 0.1%, stop the replacement, start timing when the reaction kettle is heated to 80℃, after 3h of reaction, filter the reaction liquid in the reaction kettle to collect the filtrate, first recover methanol through a 67℃ distillation kettle, after the recovery is completed, transfer the reaction liquid to a rectification tower, remove the byproduct water at 110℃, then heat to 125℃ to collect tetramethylethylenediamine, detect the obtained tetramethylethylenediamine, the yield is 92.71% and the purity is 98.25%.

[0079] Example 9:

[0080] A method for preparing tetramethylethylenediamine at low temperature, specifically comprising the following steps:

[0081] Take 0.2 mol of methanol into the reaction kettle, control the temperature of the reaction kettle at 50℃, take 0.05 mol of N,N-dimethylethylenediamine into the reaction kettle and mix with methanol, after the addition of N,N-dimethylethylenediamine is completed, take 540 mg of modified manganese ion catalyst in preparation example 6 into the reaction kettle and mix with N,N-dimethylethylenediamine and methanol, close the kettle cover, replace the air in the kettle with argon, detect the oxygen content in the kettle as 0%, stop the replacement, start timing when the reaction kettle is heated to 90℃, after 3h of reaction, filter the reaction liquid in the reaction kettle to collect the filtrate, first recover methanol through a 67℃ distillation kettle, after the recovery is completed, transfer the reaction liquid to a rectification tower, remove the byproduct water at 110℃, then heat to 130℃ to collect tetramethylethylenediamine, detect the obtained tetramethylethylenediamine, the yield is 93.21% and the purity is 99.64%.

[0082] Comparative example 1:

[0083] Different from example 9, the modified manganese ion catalyst is replaced with manganese chloride, and the rest of the conditions remain unchanged, the yield of tetramethylethylenediamine is measured as 4.82%, and the purity is 32.46%.

[0084] Comparative example 2:

[0085] Different from example 9, the modified manganese ion catalyst is replaced with manganese nitrate, and the rest of the conditions remain unchanged, the yield of tetramethylethylenediamine is measured as 8.54%, and the purity is 40.61%.

[0086] Comparative example 3:

[0087] Different from example 9, the modified manganese ion catalyst is replaced by manganese nitrate, and the rest of the conditions remain unchanged. The yield of tetramethylethylenediamine is 6.91%, and the purity is 37.59%.

[0088] The above examples have described the technical solutions and beneficial effects of the present application in detail. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. A process for the low temperature preparation of tetramethylethylenediamine, characterized in that, The method comprises the following steps: Methanol is placed in a reaction kettle, a diamine compound is added to the reaction kettle and stirred and mixed; After the diamine compound is completely added, a manganese ion modified catalyst is added to the reaction kettle and mixed with the methanol and the diamine compound; After the manganese ion modified catalyst is completely added, the reaction kettle is replaced with an inert gas, and after the replacement is completed, the reaction kettle is subjected to a temperature rising reaction to obtain a reaction liquid; The reaction liquid is filtered to collect a filtrate, and the filtrate is subjected to distillation treatment in sequence to obtain tetramethyl ethylenediamine; The diamine compound comprises N,N'-dimethylethylenediamine, N,N-dimethylethylenediamine or ethylenediamine; The preparation method of the manganese ion modified catalyst comprises the following steps: Metal manganese ions, a ligand compound and dimethylformamide are mixed, subjected to ultrasonic treatment, reacted at 70-90 DEG C for 30-60 min, and then cooled to precipitate crystals, the crystals are vacuum dried to obtain a solid, and the solid is calcined to obtain the manganese ion modified catalyst; The metal manganese ions comprise manganese chloride, manganese nitrate or manganese carbonate, and the ligand compound comprises acetylacetone, ethylenediaminetetraacetic acid or trifluoroacetyl triflate.

2. The process for low temperature preparation of tetramethylethylenediamine as claimed in claim 1 wherein, The molar ratio of the methanol to the diamine compound is 2-4:

1.

3. The process for low temperature preparation of tetramethylethylenediamine as claimed in claim 1 wherein, The temperature when the diamine compound is added to the reaction kettle is 0-50 DEG C.

4. The process for low temperature preparation of tetramethylethylenediamine as claimed in claim 1 wherein, The amount of the manganese ion modified catalyst is 1%-5% of the total mass of the methanol and the diamine compound.

5. The process for low temperature preparation of tetramethylethylenediamine as claimed in claim 1 wherein, The mass ratio of the metal manganese ions to the ligand compound is 1:1-5.

6. The process for low temperature preparation of tetramethylethylenediamine as claimed in claim 1 wherein, The inert gas comprises nitrogen, helium or argon.

7. The process for low temperature preparation of tetramethylethylenediamine as claimed in claim 1 wherein, The temperature at which the reaction kettle is subjected to a temperature rising reaction is 60-90 DEG C.