Co-production method of N,N,N'-trimethyl-N'-(3-aminopropyl)bis(aminoethyl) ether

Abstract

The invention discloses a method for co-producing N,N,N'-trimethyl-N'-(3-aminopropyl)bis(aminoethyl)ether (NE300 for short) and bis(2-dimethylaminoethyl)ether (BDMAEE for short), wherein sulfuric acid, DMEA, acrylonitrile and methylethanolamine are used as starting materials, and the process mainly comprises the following steps: synthesis of sulfate, synthesis of N-(3-aminopropyl)-N-methylethanolamine and synthesis of NE300. The overall reaction of the invention has the characteristics of safety, environmental protection, low cost and simple process, and therefore has good application prospect and is suitable for industrial production.

Description

Technical Field

[0001] The invention belongs to the field of chemical industry and relates to a method for synthesizing special amines, in particular to a method for synthesizing N,N,N′-trimethyl-N′-(3-aminopropyl)bis(aminoethyl) ether (NE300 for short) and bis(2-dimethylaminoethyl) ether (BDMAEE for short) by co-production. Background Art

[0002] N,N,N′-trimethyl-N′-(3-aminopropyl)bis(aminoethyl) ether, CAS No. 189253-72-3, molecular formula C 10 H 25 N 3 O, referred to as NE300, its structural formula is shown in Formula 1, it is a new type of polyurethane foaming catalyst, its foaming effect is better than the more common N-(3-dimethylaminopropyl)-N,N-diisopropanolamine, triethanolamine and other catalysts, and its use in the soft foam, semi-rigid foam and rigid foam industries can reduce the bad smell of sponge products and the volatilization of VOC. In general, NE300 is a polyurethane foaming catalyst with excellent performance.

[0003]

[0004] In 1998, patent US05824711 synthesized NE300 using (N,N-dimethylaminoethoxy)ethanol, methylamine and acrylonitrile as raw materials. The reaction process is as follows: First, under the conditions of 195℃ and 1.48MPa, (N,N-dimethylaminoethoxy)ethanol and methylamine are reduced by high temperature and high pressure to form Cu / Zn / Al 2 O 3 The catalyst was used to synthesize N,N,N′-trimethylbis(aminoethyl)ether, with a mass yield of 38.2%. Then, at 50°C, N,N,N′-trimethylbis(aminoethyl)ether and acrylonitrile were subjected to an addition reaction until the conversion rate exceeded 99%, thereby obtaining N,N,N′-trimethyl-N′-(2-cyanoethyl)bis(aminoethyl)ether. Finally, at 90°C, 8.2MPa of hydrogen, 10wt% NH 3 Under the reaction conditions, NE300 was obtained under the catalysis of chromium-modified sponge nickel.

[0005] Patent CN105884629 uses methylethanolamine, acrylonitrile and dimethylethanolamine (DMEA) as raw materials to prepare NE300. There are two synthetic routes:

[0006] Route 1: First, DMEA and thionyl chloride are reacted to obtain a reaction liquid; then the reaction liquid is added to a solution obtained after the reaction of methylethanolamine and metallic sodium, and N,N,N′-trimethylbis(aminoethyl)ether is obtained after distillation, with a mass yield of 62.6% and a purity of more than 96%; finally, the reaction liquid obtained after the addition of N,N,N′-trimethylbis(aminoethyl)ether and acrylonitrile is reduced and hydrogenated under the catalysis of skeleton nickel, palladium carbon, ruthenium carbon and other catalysts to obtain NE300, with a mass yield of 92.7% after distillation and a product purity of more than 98%.

[0007] Route 2: First, methylethanolamine and acrylonitrile are reacted, and then reduction hydrogenation is carried out under the action of a catalyst to obtain N-(3-aminopropyl)-N-methylethanolamine, and the mass yield after distillation is 62.5%; then DMEA is reacted with thionyl chloride in toluene to obtain a mixed solution, and the mixed solution is added to a sodium alcohol solution of N-(3-aminopropyl)-N-methylethanolamine to obtain NE300, and the mass yield after distillation is 77.9%, and the product purity exceeds 96%.

[0008] The above two routes have the following disadvantages: the former needs to react at a relatively high pressure and temperature, which is not conducive to production and has potential safety hazards. In addition, the raw material (N,N-dimethylaminoethoxy)ethanol is expensive. The boiling points of the two raw materials, (N,N-dimethylaminoethoxy)ethanol and methylamine, are quite different, and it is difficult to maintain the same state for reaction. Although the latter has made improvements on the raw materials, thionyl chloride is used as the raw material. Thionyl chloride is highly corrosive and is not easy to be produced on a large scale. In addition, the overall reaction yield is not high, and there is still much room for improvement.

[0009] Bis(2-dimethylaminoethyl) ether, CAS number: 3033-62-3, molecular formula: C 8 H 20 N 2 O, referred to as BDMAEE.

[0010] BDMAEE is a highly efficient tertiary amine polyurethane foaming agent, which is suitable for the production of almost all foam plastic products, mainly used for the production of soft foam products, especially for high resilience and RIM products. It is characterized by high catalytic activity, stable foaming, high tolerance to tin, easy adjustment of formula, and the physical and chemical properties of products produced with it, such as resilience and elongation, are better than other products.

[0011] At present, the main methods for the synthesis of BDMAEE include bis(2-dimethylaminoethyl) ether, such as sodium alcoholate etherification method (patent CN102786427), DMEA dehydration method (patent US6150559), diethylene glycol gas phase dehydration method (patent US4922023), etc.

[0012] The current NE300 synthesis method has many side reactions, poor selectivity, low yield of the target product, and high pollution. There is an urgent need for a new NE300 synthesis route with good selectivity, high yield, and environmental friendliness. Summary of the invention

[0013] The technical problem to be solved by the present invention is to provide a method for co-producing N,N,N'-trimethyl-N'-(3-aminopropyl)bis(aminoethyl) ether (NE300 for short) and bis(2-dimethylaminoethyl) ether (BDMAEE for short).

[0014] In order to solve the above technical problems, the present invention provides a method for co-producing N,N,N′-trimethyl-N′-(3-aminopropyl)bis(aminoethyl) ether (NE300 for short) and bis(2-dimethylaminoethyl) ether (BDMAEE for short), comprising the following steps:

[0015] 1) Synthesis of sulfate esters: that is, esterification of dimethylethanolamine (DMEA) with sulfuric acid:

[0016] Under stirring conditions, DMEA is added dropwise to sulfuric acid (98% sulfuric acid) (the system temperature is controlled at 30-40°C during the slow dropwise addition), and after the dropwise addition is completed, the temperature is raised to 130-190°C and kept warm for reaction for 5-8 hours to obtain an esterification liquid; the water generated during the reaction is taken out of the system; the molar ratio of sulfuric acid: DMEA = 2.5-5.0:1;

[0017] Note: During the reaction, continuous stirring promotes dispersion and a small flow of nitrogen is used to remove the generated water to speed up the reaction. After the reaction is completed, the temperature is cooled to room temperature to obtain a viscous dark red esterification liquid;

[0018] 2) Synthesis of N-(3-aminopropyl)-N-methylethanolamine:

[0019] Under stirring conditions and at 50-70° C., acrylonitrile is added dropwise to methylethanolamine (during the addition, the temperature of the system is controlled not to change by more than 5° C.), and after the addition is completed, the temperature is kept warm for 6-12 hours to perform an addition reaction to obtain an addition reaction liquid (i.e., (2-cyanoethyl)(2-hydroxyethyl)methylamine reaction liquid); the molar ratio of methylethanolamine to acrylonitrile is 0.8-1.2:1;

[0020] The addition reaction liquid is transferred to an autoclave, a hydrogenation catalyst is added, and hydrogen is introduced to control the pressure in the autoclave to be 2.5 to 5.0 MPa (i.e., the hydrogen pressure is 2.5 to 4.5 MPa), and the reaction is carried out at a temperature of 50 to 120° C. for 6 to 12 hours to obtain an N-(3-aminopropyl)-N-methylethanolamine reaction liquid; the amount of the hydrogenation catalyst is 3 to 10 wt % of the addition reaction liquid (i.e., the (2-cyanoethyl) (2-hydroxyethyl) methylamine reaction liquid);

[0021] The N-(3-aminopropyl)-N-methylethanolamine reaction liquid is subjected to solid-liquid separation, the separated solid is a recyclable hydrogenation catalyst, and the separated liquid is subjected to rectification to obtain N-(3-aminopropyl)-N-methylethanolamine;

[0022] 3) NE300 synthesis:

[0023] Under stirring conditions, the N-(3-aminopropyl)-N-methylethanolamine obtained in step 2) is mixed with a solvent, a base is added, the temperature is raised to 70-120° C., and the esterification liquid obtained in step 1) is then added dropwise (addition: the temperature change of the system is controlled not to exceed 5° C.), and the temperature is kept (70-120° C.) for reaction for 5-9 hours;

[0024] The molar ratio of the N-(3-aminopropyl)-N-methylethanolamine to the DMEA in step 1) is 0.2 to 0.5:1;

[0025] The molar ratio of the alkali to the sulfuric acid in step 1) is 1.1 to 2.4:1;

[0026] After the reaction, sulfuric acid is added dropwise to adjust the pH to 11-12, and the sulfate (including that generated by the reaction and that generated by adjusting the pH) is removed by filtration. The filtrate obtained by filtration is first distilled under reduced pressure (to recover the solvent and the generated water), and then distilled to obtain BDMAEE (2.0 kPa, 75-80°C) and NE300 (2.0 kPa, 145-150°C), respectively.

[0027] illustrate:

[0028] During the distillation process, unreacted DMEA is also obtained.

[0029] If the alkali used is sodium hydroxide, sodium carbonate, etc., the resulting sulfate is sodium sulfate; if the alkali used is potassium carbonate, etc., the resulting sulfate is potassium sulfate.

[0030] As an improvement of the co-production method of the present invention:

[0031] The hydrogenation catalyst in step 2) is Raney Ni (Ni content is 90%), Raney Cu (Cu content is 90%), Raney Co (Co content is 90%), Pt / C (Pt content is 5%), Pd / C (Pd content is 20%), Cr-Al 2 O 3 、Cu-Al 2 O 3 .

[0032] As a further improvement of the co-production method of the present invention:

[0033] The solvent in step 3) is toluene, cyclohexane, xylene, n-heptane, dichloroethane, tetrahydrofuran, dioxane, DMEA, and water; the ratio of N-(3-aminopropyl)-N-methylethanolamine to the solvent is about 1 g / 10-15 ml.

[0034] As a further improvement of the co-production method of the present invention:

[0035] The alkali in step 3) is sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium methoxide, or sodium ethoxide.

[0036] As a further improvement of the co-production method of the present invention, in step 3):

[0037] When the alkali is sodium hydroxide, potassium hydroxide, sodium bicarbonate, potassium bicarbonate, sodium methoxide, or sodium ethoxide, the molar ratio of the alkali to the sulfuric acid in step 1) is 2.0 to 2.4:1

[0038] When the alkali is sodium carbonate or potassium carbonate, the molar ratio of the alkali to the sulfuric acid in step 1) is 1.1-1.3:1.

[0039] The invention discloses a production method for co-producing NE300 and BDMAEE by taking sulfuric acid, DMEA, acrylonitrile and methylethanolamine as starting raw materials.

[0040] The present invention provides an efficient and green preparation method based on the integrated technology of reaction and separation process; specifically, it is a synthesis method for co-producing NE300 and BDMAEE, and the reaction process mainly includes: synthesis of sulfate ester, synthesis of N-(3-aminopropyl)-N-methylethanolamine and synthesis of NE300:

[0041]

[0042] The synthesis of N-(3-aminopropyl)-N-methylethanolamine in step 2) of the present invention comprises:

[0043] First, methylethanolamine and acrylonitrile undergo addition reaction to obtain an addition reaction liquid - (2-cyanoethyl) (2-hydroxyethyl) methylamine reaction liquid;

[0044] Secondly, the cyano group is reduced to obtain N-(3-aminopropyl)-N-methylethanolamine reaction solution; in this step, the gas in the autoclave is converted three times with hydrogen after the autoclave is sealed, and then hydrogen is introduced to control the pressure in the autoclave;

[0045] Finally, the catalyst was recovered by filtration, and the filtrate was distilled to obtain N-(3-aminopropyl)-N-methylethanolamine (2.0 kPa,

[0046] 125~130℃).

[0047] The present invention develops a synthesis method for co-producing NE300 and BDMAEE using acrylonitrile, methylethanolamine, sulfuric acid and DMEA as main raw materials. The present invention has the following technical advantages:

[0048] 1) Using low-cost DMEA, sulfuric acid, methylethanolamine, etc. as initial raw materials greatly reduces production costs;

[0049] 2) Using green catalytic hydrogenation process, cheap catalysts such as Raney Ni can be recycled and reused, which is more economical;

[0050] 3) Using sulfuric acid instead of thionyl chloride avoids the production of toxic and harmful gases such as sulfur dioxide and hydrogen chloride.

[0051] 4) Using sulfate (i.e., the esterification liquid obtained in step 1) as the etherification reagent avoids the use of chlorinated substances in the traditional process, is easier to post-process, and has low corrosiveness;

[0052] 5) Synthesize NE300 by co-production: In step 3), by adding DMEA esterification solution, N-(3-aminopropyl)-N-methylethanolamine can be etherified to generate NE300; NE300 is relatively simple to separate, and the by-product of the reaction is BDMAEE, which is a special amine with high economic value.

[0053] In summary, the present invention uses DMEA, sulfuric acid, methylethanolamine, etc. as raw materials, synthesizes NE300 through multi-step reactions, and the final reaction solution is simply distilled to remove the low-boiling point solvent, and then the product with high purity can be obtained through rectification, and the main by-product BDMAEE is a widely used polyurethane foaming agent. The overall reaction has the characteristics of safety, environmental protection, low cost and simple process, and therefore has good application prospects and is suitable for industrial production. DETAILED DESCRIPTION

[0054] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto:

[0055] The stirring speed in the present invention is 500 to 1000 rpm.

[0056] Slowly adding in step 1): controlling the system temperature between 30 and 40°C;

[0057] Step 2): the temperature of the system is controlled to not exceed 5°C;

[0058] Step 3): the temperature of the system is controlled to not exceed 5°C;

[0059] The sulfuric acid used was 98% sulfuric acid.

[0060] Raney Ni (Ni content is 90%), Raney Cu (Cu content is 90%), Raney Co (Co content is 90%), Pt / C (Pt content is 5%), and Pd / C (Pd content is 20%).

[0061] Embodiment 1:

[0062] 1) 2.00 mol (about 200 g) of 98% sulfuric acid was added to a three-necked flask, and 0.72 mol of DMEA (about 64 g) was slowly added dropwise thereto under stirring, and the temperature was raised to 150°C for reaction. A small flow of nitrogen gas was used to remove the generated water vapor to accelerate the reaction rate. The temperature was kept for reaction for 8 hours and then cooled (to room temperature) to obtain a viscous dark red esterification liquid;

[0063] 2) 0.21 mol of methylethanolamine (about 16.0 g) was added to a three-necked flask, stirred and maintained at 50°C, and 0.20 mol (10.6 g) of acrylonitrile was gradually added dropwise thereto. After the addition was completed, the mixture was kept warm for 6 hours to obtain an addition reaction solution;

[0064] The addition reaction liquid was transferred to an autoclave, and 2.0 g of Raney Ni catalyst was added thereto, that is, the amount of catalyst was 7.5 wt % of the addition reaction liquid. After sealing, the gas in the autoclave was converted with hydrogen three times, and the reaction was carried out at 80° C. and 4.0 MPa hydrogen pressure for 8 hours to obtain N-(3-aminopropyl)-N-methylethanolamine reaction liquid;

[0065] The N-(3-aminopropyl)-N-methylethanolamine reaction liquid was filtered, and the filter cake was a RaneyNi catalyst that could be recovered and directly used; the filtrate was distilled at a pressure of 2.0 kPa, and the fractions at 125 to 130° C. were collected to obtain 24.6 g of N-(3-aminopropyl)-N-methylethanolamine (liquid).

[0066] 3) Mix 24.6 g (0.19 mol) of N-(3-aminopropyl)-N-methylethanolamine and 300 mL of toluene, add 4.0 mol (about 160 g) of solid sodium hydroxide powder, stir evenly, heat to 90° C., gradually dropwise add the reaction solution obtained in step 1), and react for 7 h;

[0067] After the reaction, concentrated sulfuric acid was added dropwise to the obtained reaction solution to adjust the pH to 11-12, and the solution was filtered to remove sulfate. The filtrate obtained by filtration was first distilled under reduced pressure (pressure of 2 kPa) (to recover the solvent and generated water), and then rectified to obtain NE300 35.1 g (2.0 kPa, 125-130° C.), BDMAEE 26.3 g (2.0 kPa, 75-50° C.), and DMEA 20.1 g (2.0 kPa, 35-40° C.), respectively.

[0068] The purity of NE300 is 99.1%; the purity of BDMAEE is 98.7%.

[0069] The yield of NE300 was 86.4%.

[0070] Examples 2 to 12: With respect to the above Example 1, one or more process parameters (as shown in Table 1) were changed, the amount of MDEA in step 1) was fixed at 64.0 g, the amount of methylethanolamine in step 2) was fixed at 16.0 g, and the rest was referred to Example 1. The specific results are listed in Table 1 below.

[0071] Table 1

[0072]

[0073]

[0074] illustrate:

[0075] 1. Addition molar ratio refers to the molar ratio of methylethanolamine: acrylonitrile.

[0076] 2. Alkali amount / eq refers to the molar ratio of the alkali to the sulfuric acid in step 1).

[0077] 3. In Example 12, since the reactant DMEA is directly used as the solvent, only the generated water is distilled and recovered during the reduced pressure distillation of the filtrate.

[0078] 4. The purity of NE300 obtained in Table 1 is ≥98%; the purity of BDMAEE is ≥98%.

[0079] Examples 14 to 18: Catalyst recycling examples:

[0080] Examples 14 to 18 are multiple cycles based on the catalyst recovered in Example 1, with new catalyst (Raney Ni catalyst) accounting for 10% of the recovered catalyst added in each cycle, and the total amount of catalyst remained unchanged; the other conditions are the same as in Example 1, and the results are shown in Table 2 below.

[0081] Table 2

[0082] Example 14 15 16 17 18 Cycle times 1 2 3 4 5 BDMAEE / g 26.8 25.7 27.8 24.9 24.6 NE300 / g 35.0 34.1 33.2 34.8 33.5

[0083] Note: The purity of NE300 obtained in Table 2 is ≥98%; the purity of BDMAEE is ≥98%.

[0084] Examples 19 to 23. Examples of catalyst recycling

[0085] Examples 19 to 23 are multiple cycles based on the catalyst recovered in Example 2, with new catalyst (Pt / C) accounting for 10% of the recovered catalyst added in each cycle, and the total amount of catalyst remained unchanged; the other conditions are the same as in Example 2, and the results are shown in Table 3 below.

[0086] Table 3

[0087] Example 19 20 21 22 23 Recycling times 1 2 3 4 5 BDMAEE / g 22.0 24.5 23.9 25.7 22.4 NE300 / g 33.4 34.8 32.4 33.7 32.7

[0088] Note: The purity of NE300 obtained in Table 3 is ≥98%; the purity of BDMAEE is ≥98%.

[0089] Comparative Example 1: The "98% sulfuric acid" in step 1) of Example 1 was changed to 68% nitric acid (containing 2.0 mol nitric acid), and the rest was referred to Example 1. The result was: NE300 could not be generated.

[0090] Comparative Example 2: The esterification temperature in step 1) of Example 1 was lowered from 150° C. to 80° C., and the rest was referred to Example 1. The result was that NE300 could not be generated.

[0091] Comparative Example 3: The etherification temperature in step 3) of Example 1 was reduced from 90° C. to 40° C., and the rest was referred to Example 1. The result was that NE300 could not be generated.

[0092] Comparative Example 4: 60 g of sodium hydroxide in step 3) of Example 1 was replaced with 60 g of sodium chloride, and the rest was referred to Example 1. The result was that NE300 could not be generated.

[0093] Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. A method for co-producing N,N,N'-trimethyl-N'-(3-aminopropyl)bis(aminoethyl) ether and bis(2-dimethylaminoethyl) ether, characterized in that The following steps are involved: 1) Synthesis of sulfate esters: Under stirring conditions, DMEA is added dropwise to sulfuric acid, and after the addition is completed, the temperature is raised to 130°C to 190°C, and the temperature is kept for reaction for 5 to 8 hours to obtain an esterification liquid; water generated during the reaction is taken out of the system; the molar ratio of sulfuric acid to DMEA is 2.5 to 5.0:1; 2) Synthesis of N-(3-aminopropyl)-N-methylethanolamine: Under stirring conditions and at 50-70° C., acrylonitrile is added dropwise to methylethanolamine, and after the addition is completed, the temperature is kept warm for an addition reaction for 6-12 hours to obtain an addition reaction liquid; the molar ratio of methylethanolamine to acrylonitrile is 0.8-1.2:1; The addition reaction liquid is transferred to an autoclave, a hydrogenation catalyst is added, and hydrogen is introduced to control the pressure in the autoclave to be 2.5-5.0 MPa, and the reaction is carried out at a temperature of 50-120° C. for 6-12 hours to obtain an N-(3-aminopropyl)-N-methylethanolamine reaction liquid; the amount of the hydrogenation catalyst is 3-10 wt % of the addition reaction liquid; The N-(3-aminopropyl)-N-methylethanolamine reaction liquid is subjected to solid-liquid separation, the separated solid is a recyclable hydrogenation catalyst, and the separated liquid is subjected to rectification to obtain N-(3-aminopropyl)-N-methylethanolamine; 3) NE300 synthesis: Under stirring conditions, the N-(3-aminopropyl)-N-methylethanolamine obtained in step 2) is mixed with a solvent, a base is added, the temperature is raised to 70-120° C., and the esterification liquid obtained in step 1) is then added dropwise, and the reaction is kept warm for 5-9 hours; The molar ratio of the N-(3-aminopropyl)-N-methylethanolamine to the DMEA in step 1) is 0.2-0.5:1; The molar ratio of the base to the sulfuric acid in step 1) is 1.1-2.4:1; the base is sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium methoxide, sodium ethoxide; After the reaction, sulfuric acid was added dropwise to adjust the pH to 11-12, and the sulfate was removed by filtration. The filtrate obtained by filtration was first distilled under reduced pressure and then rectified to obtain BDMAEE and NE300, respectively.

2. The co-production method according to claim 1, characterized in that: The hydrogenation catalyst in step 2) is Raney Ni, Raney Cu, Raney Co, Pt / C, Pd / C, Cr-Al2O3, Cu-Al2O3.

3. The co-production method according to claim 2, characterized in that: The solvent in step 3) is toluene, cyclohexane, xylene, n-heptane, ethylene dichloride, tetrahydrofuran, dioxane, DMEA, or water.

4. The co-production method according to claim 3, characterized in that In the step 3): When the base is sodium hydroxide, potassium hydroxide, sodium bicarbonate, potassium bicarbonate, sodium methoxide, or sodium ethoxide, the molar ratio of the base to the sulfuric acid in step 1) is 2.0 to 2.4:1; When the alkali is sodium carbonate or potassium carbonate, the molar ratio of the alkali to the sulfuric acid in step 1) is 1.1-1.3:1.

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