A preparation method of N,N,N',N'-tetramethyldipropylenetriamine

Abstract

The application belongs to the field of chemical industry, and particularly relates to a preparation method of N,N,N',N'-tetramethyl diacrylamine, which comprises the following steps: hydrogenation reaction is carried out by introducing hydrogen into an amine group propyl cyanide compound, a dimethylamine aqueous solution and a catalyst; under the protection of inert gas, solid-liquid separation (filtration) is carried out on the obtained hydrogenated material, so that a filtrate and a filter cake are obtained; and the filtrate is subjected to rectification, so that N,N,N',N'-tetramethyl diacrylamine (2(DMAP)A) is obtained. The application has the advantages of simple process, mild conditions, green environmental protection, high product yield and facilitation of industrial production.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of chemical industry, and particularly relates to a preparation method of N, N, N', N'-tetramethyl diacetylene triamine (2(DMAP)A for short). BACKGROUND

[0002] 2(DMAP)A is a colorless to light yellow transparent liquid, and its molecular formula is C 10 H 25 N3, and its CAS number is 6711-48-4; 2(DMAP)A is easily soluble in water, alcohol, ether and toluene and other organic solvents. It is a balanced polyurethane catalyst, and can be used for polyether type polyurethane soft foam and polyurethane CASE material, and can also be used as an epoxy resin curing agent and accelerator, a copper removal agent for semiconductor materials and a raw material for cationic surfactants. The structural formula is shown as formula 1:

[0003]

[0004] Formula 1, 2(DMAP)A structural formula

[0005] The synthesis method of 2(DMAP)A mainly uses 3-dimethylaminopropyl cyanide (DMAPN for short) or 3-dimethylaminopropyl amine (DMAPA for short) as raw materials for hydrogenation reaction.

[0006] Patent US2008161611 of BASF reports that 2(DMAP)A is generated under hydrogenation conditions by using DMAPA as raw material and noble metals Pd, Pt supported on Al2O3 or SiO2 as catalyst, and the reaction is carried out in a tower reactor. The equipment requirement is high, and the raw material conversion rate is less than 50%.

[0007] Patent CN106866428A uses DMAPA and DMAPN as raw materials, and adds a supported nano catalyst for hydrogenation reaction in a high-pressure reaction kettle to prepare 2(DMAP)A. The selectivity of the target product can reach 92%, but the yield is low, the highest is 50.6%, and the reaction time is more than 10h, and the production efficiency is low.

[0008] Patent CN11389654A uses acrylonitrile and dimethylamine as raw materials, and uses two fixed-bed reactors in series. The raw material is first subjected to addition reaction in the No. 1 reactor to obtain an intermediate product, and then subjected to hydrogenation reaction in the No. 2 reactor to obtain DMAPA, 2(DMAP)A and 3(DMAP)A. This method can simultaneously co-produce three products, which is good in economy, but the catalyst in the No. 2 reactor is a bimetallic catalyst supported on a molecular sieve, and the preparation process is complex; the yield of 2(DMAP)A can only reach 33.3% at most, and the yield is low.

[0009] Patent CN111285772B uses DMAPA and DMAPN as raw materials for a hydrogenation reaction to produce 2(DMAP)A. The reaction conversion rate can reach over 95%, and the selectivity of the product, tetramethyldipropylenetriamine, can reach over 90%. This method uses palladium-rhodium graphene as a catalyst. Since palladium and rhodium are in nanomolecular form, the catalyst requirements are high and the cost is relatively high.

[0010] In summary, the preparation of 2(DMAP)A has the problems of low yield and high requirements for catalysts, reaction equipment or processes.

[0011] Dimethylaminopropyl(propionitrile)amine (DMAP(PN)A) with CAS number 69852-45-5 is an organic intermediate; di(propionitrile)amine (2(PN)A) with CAS number 111-94-4 is currently known to be used as a chromatographic stationary liquid and pharmaceutical intermediate. Summary of the Invention

[0012] The technical problem to be solved by the present invention is to provide a method for preparing 2(DMAP)A, which has a simple process and a high yield, and a simple catalyst, low cost and reusability.

[0013] In order to solve the above technical problems, the present invention provides a method for preparing N,N,N',N'-tetramethyldipropylenetriamine (abbreviated as 2(DMAP)A), comprising the following steps:

[0014] 1) Hydrogenation reaction:

[0015] Add an aminopropionitrile compound, a dimethylamine (DMA) aqueous solution, and a catalyst to a reactor, introduce carbon dioxide (CO2) or an inert gas (e.g., nitrogen) or a mixture of the two, and control the pressure in the reactor to be 0.1-0.3 MPa; then introduce hydrogen to control the pressure in the reactor to be 0.5-10 MPa (preferably 0.5-5 MPa, further 0.5-3 MPa), and heat to 50-150° C. (preferably 50-110° C., further 50-70° C.) for reaction, and terminate the hydrogenation reaction (reaction time is about 3-10 hours, preferably 4-9 hours) when the pressure in the high-pressure reactor does not decrease even when hydrogen is not introduced (the hydrogen inlet valve is closed); then cool to room temperature to obtain a hydrogenated material;

[0016] The molar ratio of cyano group to dimethylamine (DMA) in the aminopropionitrile compound is 1:1.01-2 (preferably 1:1.01-1.5);

[0017] The weight ratio of the catalyst to the aminopropionitrile compound is 3 to 20 wt% (preferably 3 to 15%);

[0018] 2) Solid-liquid separation:

[0019] Under the protection of an inert gas (e.g., nitrogen), the hydrogenated material obtained in step 1) is subjected to solid-liquid separation (filtration) to obtain a filtrate and a filter cake, respectively;

[0020] Note: The catalyst is recovered for reuse (the filter cake is a recoverable catalyst), and the filtrate is subjected to the distillation of step 3).

[0021] 3) Distillation:

[0022] The filtrate was distilled to obtain N,N,N',N'-tetramethyldipropylenetriamine (2(DMAP)A).

[0023] As an improvement to the preparation method of N,N,N',N'-tetramethyldipropylenetriamine of the present invention:

[0024] The catalyst in step 1) is a Raney nickel catalyst, containing 90-93% nickel, 5-8% aluminum, 0.1-0.3% copper, 0.4-1.0% platinum, 0.4-1.0% ruthenium, and 0.4-1.5% molybdenum.

[0025] The above % is the mass content.

[0026] As a further improvement of the preparation method of N,N,N',N'-tetramethyldipropylenetriamine of the present invention:

[0027] The aminopropionitrile compound is at least one of dimethylaminopropyl (propionitrile) amine (abbreviated as DMAP(PN)A) and di(propionitrile) amine (abbreviated as 2(PN)A) (ie, a mixture of one or two).

[0028] As a further improvement of the preparation method of N,N,N',N'-tetramethyldipropylenetriamine of the present invention:

[0029] The mass concentration of the dimethylamine (DMA) aqueous solution in step 1) is (40±5) wt%.

[0030] As a further improvement of the preparation method of N,N,N',N'-tetramethyldipropylenetriamine of the present invention, the step 3) is:

[0031] The filtrate obtained in step 2) is added to a distillation apparatus, and first subjected to atmospheric distillation, followed by vacuum distillation. The transition fraction (105-118°C / 10 mHg fraction, which is applied to the distillation step of the next batch reaction) is collected and further distilled to obtain 2(DMAP)A (120-130°C / 10 mHg fraction).

[0032] Description: Atmospheric distillation, collection of waste gas (30-50℃ / 760mmHg fraction); collection of water (100-102℃ / 760mmHg fraction); waste gas mainly consists of excess dimethylamine and ammonia; after collection, conventional subsequent treatment can be carried out to prevent environmental pollution.

[0033] As a further improvement of the preparation method of N,N,N',N'-tetramethyldipropylenetriamine of the present invention:

[0034] First, replace the air in the kettle with inert gas (such as nitrogen) and hydrogen (three times each), then introduce CO2 or inert gas (such as nitrogen) or a mixture of the two, and then introduce hydrogen.

[0035] The reaction formula involved in the present invention is as follows:

[0036]

[0037] In the current prior art, there is no route for preparing 2(DMAP)A) by using DMAP(PN)A) and 2(PN)A as raw materials.

[0038] DMAP(PN)A) and 2(PN)A, which are known compounds, can be prepared according to the applicant's existing patents CN117209398A and CN116803485A.

[0039] The technical advantages of the present invention are:

[0040] (1) The catalytic hydrogenation process is simple and the conditions are mild.

[0041] (2) The catalyst is simple, recyclable and has high atomic utilization rate.

[0042] (3) High raw material conversion rate and good product selectivity.

[0043] In summary, the present invention uses an aminopropionitrile compound and a DMA aqueous solution as raw materials, performs catalytic hydrogenation in an atmosphere of CO2 or an inert gas (e.g., N2), or a mixture of the two, and obtains the product through solid-liquid separation and distillation. The process is simple, mild, environmentally friendly, and has a high product yield, making it suitable for industrial production. DETAILED DESCRIPTION

[0044] The present invention is further described below with reference to specific embodiments, but the protection scope of the present invention is not limited thereto:

[0045] The product obtained by the present invention and the standard sample of 2(DMAP)A were injected by gas chromatography, and the results were completely consistent, thereby proving that the product obtained by the present invention is indeed 2(DMAP)A.

[0046] Example 1, preparation method of Raney nickel catalyst:

[0047] 20 g of nickel, 17 g of aluminum, 0.038 g of copper, 0.11 g of platinum, 0.14 g of ruthenium, and 0.16 g of molybdenum were added to a furnace for high-temperature melting to obtain a uniform alloy, which was then cooled by a high-speed rotating copper drum to obtain an alloy thin strip, which was then ground using a ball mill to obtain an alloy powder; the alloy powder was added to 120 ml of a 25% sodium hydroxide aqueous solution and stirred continuously at 70° C. for 2 h; the mixture was repeatedly washed with deionized water to neutrality, and the obtained Raney nickel catalyst was stored in ethanol for later use.

[0048] Description: Sodium hydroxide reacts with aluminum to remove most of the aluminum in the alloy, forming a porous structure.

[0049] After testing: the obtained Raney nickel catalyst has a nickel content of 91.37%, an aluminum content of 6.72%, and the rest are: copper 0.15%, platinum 0.51%, ruthenium 0.58%, and molybdenum 0.67%; the above % are mass %.

[0050] Example 1: Catalytic hydrogenation to prepare 2(DMAP)A, the following steps are carried out in sequence:

[0051] 1) Hydrogenation reaction:

[0052] To a reactor were added 170 g (1.095 mol) of DMAP(PN)A, 148.1 g (1.314 mol) of a 40 wt% aqueous solution of DMA, and 10.2 g of the Raney nickel catalyst prepared in Example 1. The air in the reactor was replaced three times with nitrogen and hydrogen, and then CO2 gas was introduced to a pressure of 0.15 MPa. Hydrogen was then introduced, and the temperature was raised to react. The pressure in the reactor was controlled at 1.5 MPa and the temperature was 70°C. The reaction was continued until the pressure in the autoclave did not decrease after closing the hydrogen inlet valve. The hydrogenation reaction was terminated. The reaction time was approximately 6 h. After completion of the reaction, the temperature was lowered (to room temperature) to obtain a hydrogenated material.

[0053] 2) Solid-liquid separation:

[0054] The obtained hydrogenated material is filtered under nitrogen protection to obtain a filter cake as the catalyst, which is then recovered and reused;

[0055] 3) Distillation:

[0056] The resulting filtrate in step 2) was subjected to distillation, initially at atmospheric pressure. The 30-50°C / 760 mmHg fraction was waste gas, primarily consisting of excess dimethylamine and ammonia. This waste gas was collected and subsequently processed conventionally to prevent environmental contamination. 86.16 g of water (100-102°C / 760 mmHg fraction) was collected.

[0057] Then, vacuum distillation was continued to collect 20.57 g of transition fraction (105-118° C. / 10 mHg fraction); and distillation was continued to obtain 176.42 g of product 2(DMAP)A (120-130° C. / 10 mHg fraction).

[0058] Example 1-1

[0059] In Example 1, “the obtained filtrate is subjected to rectification” is changed to “20.57 g of the transition fraction collected in Example 1 is added to the obtained filtrate, and then the mixture is subjected to rectification together”; the rest is the same as in Example 1.

[0060] In Examples 2 to 3, only the molar ratio of DMA(PN)A to DMA in Example 1-1 was changed, the amount of DMA(PN)A remained unchanged, the reaction time was changed with the variable, and the other conditions were the same as in Example 1-1.

[0061] In Examples 4 and 5, only the pressure of the CO2 gas introduced in Example 1-1 is changed, and the other conditions are the same as those in Example 1-1.

[0062] In Examples 6 and 7, only the amount of hydrogenation catalyst in Example 1-1 was changed, and the reaction time was changed with the variable, and the other conditions were the same as in Example 1-1.

[0063] In Examples 8 to 10, only the hydrogenation reaction pressure in Example 1-1 was changed, and the reaction time was changed with the variable, and the other conditions were the same as in Example 1-1.

[0064] In Examples 11 to 13, only the hydrogenation reaction temperature in Example 1-1 was changed, and the reaction time was changed with the variable, and the other conditions were the same as in Example 1-1.

[0065] The specific parameters and final results of Examples 1-1 to 13 are shown in Table 1.

[0066] Table 1

[0067]

[0068] N((-CN):DMA) represents the molar ratio of cyano group to dimethylamine in the aminopropionitrile compound; in Examples 1 to 13, it represents the molar ratio of DMAP(PN)A:DMA.

[0069] Examples 14-18: Application of Catalysts for Catalytic Hydrogenation

[0070] The Raney nickel catalyst (about 9.49 g) obtained by filtration in Example 1 was collected, supplemented with catalyst, and applied mechanically in the next batch of catalytic hydrogenation. The supplementary amount accounted for 10 wt % of the original Raney nickel catalyst (i.e., 1.02 g of fresh Raney nickel was added). The reaction time varied with the variables, and the remaining conditions were equivalent to those in Example 1; this was used as the first cycle (to obtain Example 14). Similarly, Examples 14 to 18 corresponding to the second to fifth cycles were obtained (each subsequent cycle required the addition of 10 wt % of catalyst). The results are shown in Table 2.

[0071] Table 2

[0072] Example Number of cycles Reaction time / h Water / g 2(DMAP)A / g 1 0 6 86.16 176.42 14 1 6 86.24 176.59 15 2 6.5 86.19 176.63 16 3 6.5 86.04 176.7 17 4 7 86.25 176.54 18 5 7 86.14 174.9

[0073] Examples 19-20: Catalytic Hydrogenation Reaction by Changing the Type of Aminonitrile Compound

[0074] Only the type of aminopropionitrile compound in Example 1 was changed, and the feeding amounts of aminopropionitrile compound, DMA aqueous solution and catalyst were changed accordingly, and the other conditions were the same as in Example 1.

[0075] The specific parameters and final results of Examples 19 to 20 are shown in Table 3.

[0076] Table 3

[0077]

[0078] Note: In Example 20, the molar ratio of DMAP(PN)A to 2(PN)A) is 1:1.

[0079] Examples 21-22: Catalytic Hydrogenation by Changing the Type of Gas Introduced

[0080] Only the type of gas introduced to a pressure of 0.15 MPa in Example 1 was changed, and the reaction time was changed accordingly. The other conditions were the same as in Example 1.

[0081] The specific parameters and final results of Examples 21 to 22 are shown in Table 4.

[0082] Table 4

[0083]

[0084] The Raney nickel catalyst in Example 1 is replaced with a corresponding Raney nickel catalyst containing "90-93% nickel, 5-8% aluminum, 0.1-0.3% copper, 0.4-1.0% platinum, 0.4-1.0% ruthenium, and 0.4-1.5% molybdenum." The catalyst dosage, hydrogenation reaction pressure, and hydrogenation reaction temperature can be adjusted within the ranges set by the present invention, and the reaction time can be changed accordingly (reaction is continued until the pressure in the autoclave does not decrease without the introduction of hydrogen). The yield of 2(DMAP)A obtained can be close to that of Example 1.

[0085] Comparative Example 1: The Raney nickel catalyst in Example 1 was replaced with "93% nickel, 7% aluminum." The amount of Raney nickel catalyst used remained unchanged (i.e., 10.2 g), and the reaction time was changed accordingly (reaction continued until the pressure in the autoclave did not drop without the addition of hydrogen); otherwise, the reaction was identical to Example 1. The yield was 143.56 g of 2(DMAP)A.

[0086] Finally, it should be noted that the above examples are merely specific embodiments of the present invention. Obviously, the present invention is not limited to the above examples and is subject to numerous variations. All variations that can be directly derived or conceived by a person of ordinary skill in the art from the disclosure of the present invention are considered to be within the scope of protection of the present invention.

Claims

1. A method for preparing N,N,N',N'-tetramethyldipropylenetriamine, characterized in that The following steps are involved: 1) Hydrogenation reaction: Adding an aminopropionitrile compound, a dimethylamine aqueous solution and a catalyst into a reactor, introducing carbon dioxide or an inert gas or a mixture of the two, controlling the pressure in the reactor to be 0.1-0.3 MPa; then introducing hydrogen, controlling the pressure in the reactor to be 0.5-10 MPa, raising the temperature to 50-150° C. for reaction, and reacting until the pressure in the high-pressure reactor does not decrease without introducing hydrogen, thereby terminating the hydrogenation reaction; then cooling the reactor to obtain a hydrogenated material; The molar ratio of cyano group to dimethylamine in the aminopropionitrile compound is 1:1.01-2; The weight ratio of the catalyst to the aminopropionitrile compound is 3 to 20 wt %; The aminopropionitrile compound is at least one of dimethylaminopropyl (propionitrile) amine and di(propionitrile) amine; The catalyst is a Raney nickel catalyst, which contains 90-93% nickel, 5-8% aluminum, 0.1-0.3% copper, 0.4-1.0% platinum, 0.4-1.0% ruthenium, and 0.4-1.5% molybdenum. 2) Solid-liquid separation: Under inert gas protection, the hydrogenated material obtained in step 1) is subjected to solid-liquid separation to obtain a filtrate and a filter cake respectively; 3) Distillation: The filtrate is distilled to obtain N,N,N',N'-tetramethyldipropylenetriamine.

2. The method for preparing N,N,N',N'-tetramethyldipropylenetriamine according to claim 1, characterized in that: The mass concentration of the dimethylamine aqueous solution in step 1) is (40±5) wt%.

3. The method for preparing N,N,N',N'-tetramethyldipropylenetriamine according to claim 2, characterized in that The step 3) is: The filtrate obtained in step 2) is added to a distillation apparatus, first subjected to atmospheric distillation, and then to vacuum distillation, the transition fraction is collected, and further distillation is continued to obtain 2(DMAP)A.

4. The method for preparing N,N,N',N'-tetramethyldipropylenetriamine according to any one of claims 1 to 3, characterized in that: First, replace the air in the kettle with inert gas and hydrogen respectively, then introduce CO2 or inert gas or a mixture of the two, and then introduce hydrogen.

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