Process for photocatalytic synthesis of diisopropylethylamine and bimetallic catalyst used

Abstract

The present application relates to the field of chemical industry, and in particular to a method for photocatalytic synthesis of diisopropylethylamine by using a bimetallic catalyst, and provides a preparation method of the bimetallic catalyst: a Pd precursor and a 3d metal salt are mixed and dissolved in deionized water, then mixed with a carrier, the pH is adjusted to 9-10, then reduced, followed by suction filtration, washing, drying, to obtain a Pd-M / TiO2 bimetallic catalyst. The present application also simultaneously provides a method for photocatalytic synthesis of diisopropylethylamine by using the bimetallic catalyst prepared by the above method: diisopropylamine and ethanol are used as raw materials, the bimetallic catalyst is used, and excitation is carried out under the irradiation of a UV lamp in an inert gas atmosphere, so as to carry out a photocatalytic reaction, and finally obtain N,N-diisopropylethylamine.

Description

Technical Field

[0001] This invention relates to the field of chemical engineering, and specifically to a method for the photocatalytic synthesis of diisopropylethylamine using a bimetallic catalyst. Background Technology

[0002] N,N-Diisopropylethylamine, with the structural formula shown in Formula 1 below, and the molecular formula C8H12H2O. 19 N, abbreviated as DIPEA, is an important organic chemical intermediate widely used in the production of pesticides and pharmaceuticals.

[0003]

[0004] The following are some of the reported methods for synthesizing diisopropylethylamine: Literature (Fine Chemicals, 2003, 20(1):60-61.) uses diisopropylamine and diethyl sulfate to synthesize diisopropylethylamine; US Patent 2692285 reports diisopropylamine and bromoethane as raw materials, with a low product yield (<50%); Japanese Patent 2851274 uses acetaldehyde and diisopropylamine as raw materials and noble metals as catalysts to synthesize DIPEA; Chinese Patent 101759571 reports using diisopropylamine and chloroethane as raw materials, MI... x Diisopropylamine was synthesized using a catalyst. Literature (Chem Eur J, 2017, 23(58): 14416-9.) reported the synthesis of diisopropylethylamine from diisopropylamine and ethanol under 0.4-2% equivalent Ru(OAc)2(CO)(DiPPF) catalysis for 24 hours, with a yield of only 15%. Chinese patent CN 111484415 A reported the synthesis of diisopropylamine from diisopropylamine and ethanol using ruthenium triphenylphosphine acetate or a mixture thereof with ferric oxide under reflux conditions, with a yield of 80%-90%. Literature (Green Chemistry, 2020, 22(3): 860-9.) reported the electrocatalytic synthesis of diisopropylethylamine from diisopropylamine and ethanol using self-made Ru supported on activated carbon fiber (ACC) as the anode and ACC as the cathode, with a yield of 15%.

[0005] Currently, the synthesis of diisopropylethylamine (DIPEA) both domestically and internationally faces several problems. For example, using diethyl sulfate as a raw material is toxic and results in large volumes of sulfur-containing wastewater; bromoethane is expensive; the yield of acetaldehyde and diisopropylamine is low; while using chloroethane and diisopropylamine as raw materials is cheaper, it still inevitably generates waste salts, leading to severe pollution. The catalytic reduction of diisopropylamine and acetaldehyde to DIPEA uses inexpensive raw materials, but the catalyst is a precious metal catalyst, requiring high temperature and pressure conditions, resulting in high cost, demanding equipment, large investment, and low yield. Using diisopropylamine and ethanol as raw materials involves a complex ruthenium catalyst, requiring large quantities, and the catalyst cannot be effectively recovered, making it unsuitable for industrial application. Electrocatalytic systems also have low yields and are not suitable for industrial use.

[0006] The literature (RSC Adv., 2015, 5, 14514–14521) uses Pd / TiO2 photocatalysis to react amines and alcohols, but this catalyst can only synthesize N-methyl compounds and nitro compounds by reduction to amines, and cannot synthesize hindered amines such as N,N-diisopropylethylamine. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a method for photocatalytic synthesis of diisopropylethylamine and the bimetallic catalyst used therein.

[0008] To solve the above technical problems, the present invention provides a method for preparing a bimetallic catalyst: Pd precursor and 3d metal salt are mixed and dissolved in deionized water, then mixed with a support, the pH is adjusted to 9-10, reduced, then filtered, washed, and dried (vacuum drying) to obtain a Pd-M / TiO2 bimetallic catalyst.

[0009] The molar ratio of Pd precursor to 3d metal salt is 0.1 to 5:1 (preferably 1 to 5:1, more preferably 1:1);

[0010] For every 0.00015–0.00019 mol of 3d metal salt, use 1 g of carrier.

[0011] Note: The first component of the bimetal is Pd, and the second component is 3d metal.

[0012] As an improvement to the preparation method of the bimetallic catalyst of the present invention, the reduction is carried out in any of the following ways:

[0013] Method 1: Reduce by adding a reducing agent:

[0014] For every 0.00015–0.00019 mol of 3d metal salt, use 0.1–0.2 g of reducing agent, reduce at 0–20 °C, and reduce for 10–0.1 h.

[0015] Method 2: Reduction under ultraviolet light, reaction under light conditions (stirring reaction) for 2-24 hours.

[0016] As a further improvement to the preparation method of the bimetallic catalyst of the present invention:

[0017] The 3d metal salt is a 3d metal nitrate or a 3d metal chloride;

[0018] The metal is any of the following: Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn.

[0019] As a further improvement to the preparation method of the bimetallic catalyst of the present invention:

[0020] The Pd precursor is PdCl2 or Pd(NO)3;

[0021] The carrier is titanium dioxide (TiO2).

[0022] As a further improvement to the preparation method of the bimetallic catalyst of the present invention:

[0023] The reducing agent is NaBH4, which is prepared into a NaBH4 solution with a concentration of 15-25 g / L before use.

[0024] As a further improvement to the preparation method of the bimetallic catalyst of the present invention: the titanium dioxide is anatase (preferably), rutile, or amorphous.

[0025] As a further improvement to the preparation method of the bimetallic catalyst of the present invention: 10 ml of deionized water is used for every 0.00015 to 0.00019 mol of Pd precursor.

[0026] This invention also provides a method for the photocatalytic synthesis of diisopropylethylamine using a bimetallic catalyst prepared by the above method:

[0027] Using diisopropylamine and ethanol as raw materials, a bimetallic catalyst is used to excite the reaction under ultraviolet light in an inert gas (nitrogen) atmosphere.

[0028] An improvement to the method for synthesizing diisopropylethylamine of the present invention includes the following steps:

[0029] 1) Under the protection of an inert gas, diisopropylamine, ethanol and a bimetallic catalyst are added to the reactor and the reaction is activated under ultraviolet light irradiation. The molar ratio of ethanol to diisopropylamine is 2 to 10:1 (preferably 3 to 7:1). 45 to 150 mg of bimetallic catalyst is used for every 0.09 mol of diisopropylamine.

[0030] The reaction temperature is 10–40℃, the reaction pressure is 0.1–0.5 MPa, and the reaction time is 5–24 hours.

[0031] 2) Filter the reactants obtained in step 1). The filter cake is a recyclable bimetallic catalyst. Dry the filtrate (using sodium sulfate) and then remove unreacted ethanol by rotary evaporation (and also remove any diisopropylamine that may not have been completely reacted) to obtain crude diisopropylethylamine.

[0032] Note: The filter cake obtained by vacuum filtration is washed three times with methanol and water alternately (to remove residual impurities attached to the filter cake), and then vacuum dried (drying at 50°C to constant weight); as a bimetallic catalyst for recycling.

[0033] 3) Distill the crude diisopropylethylamine and collect the fraction at 127.5–128.0 °C to obtain diisopropylethylamine.

[0034] As an improvement to the method for synthesizing diisopropylethylamine of the present invention: the activation reaction is carried out under magnetic stirring (stirring speed of 500-1000 rpm).

[0035] The synthetic equation for diisopropylethylamine of the present invention is as follows:

[0036]

[0037] Current routes for preparing diisopropylethylamine from ethanol are problematic. Thermal catalysis uses expensive and non-recoverable catalysts, rendering it unsuitable for industrial application. Electrocatalysis yields low results and is also not industrially feasible. To address these issues, this invention employs photocatalysis, utilizing a specially designed bimetallic photocatalyst for the efficient synthesis of N,N-diisopropylethylamine. Furthermore, the catalyst is reusable, making it suitable for industrial production.

[0038] Compared with existing methods that use diisopropylamine and ethanol as raw materials for thermocatalytic / electrocatalytic synthesis, this invention has the following advantages:

[0039] 1. Although both use the ethanol production route, this invention employs a specially designed bimetallic catalyst to efficiently synthesize N,N-diisopropylethylamine with a yield of 95% or higher. Compared to Ru(OAc)₂(CO)(DiPPF), ruthenium triphenylphosphine acetate or mixtures thereof with ferric oxide, and Ru / ACC and other Ru-based catalysts used in electrocatalysis, this method requires less catalyst and is easier to recycle. It has industrial application value.

[0040] 2. Compared with the haloalkane process and the diethyl sulfate process, it avoids toxic raw materials, and the byproduct is water, achieving zero emissions of waste, making it clean and environmentally friendly.

[0041] 3. Compared with the reductive amination process, it avoids the high temperature and high pressure production process, the reaction conditions are milder, and the equipment investment is small.

[0042] 4. This invention improves upon traditional photocatalytic alcohol amination catalysts by introducing a second metal component to generate a bimetallic synergistic effect, enabling its application in the synthesis of hindered amines. Attached Figure Description

[0043] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0044] Figure 1 The mass spectrum of the product N,N-diisopropylethylamine is shown. Detailed Implementation

[0045] The present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto:

[0046] Example 1: Preparation method of bimetallic catalyst Pd-Sc / TiO2:

[0047] Pd precursor was selected as PdCl2; 3d metal salt was selected as ScSO4; and anatase TiO2 was selected as the support.

[0048] Under normal stirring conditions (500-1000 rpm): 0.00017 mol of Pd precursor and 0.00017 mol of 3d metal salt were mixed and dissolved in 10 ml of deionized water, then mixed with 1 g of carrier. The pH was adjusted to 9-10 using a 10% KOH solution, and the resulting system was reduced at 10-20 °C. The reduction was specifically carried out by preparing a 20 g / L NaBH4 solution; adding 5-10 ml of NaBH4 solution dropwise to the system and aging at 10-20 °C for 40 min.

[0049] After reduction (aging) is complete, the mixture is filtered, the filter cake is washed (using water and methanol alternately to wash the filter cake until the pH test is neutral), and then vacuum dried (drying at 50℃ to constant weight) to obtain the Pd-Sc / TiO2 bimetallic catalyst.

[0050] Example 2: Preparation method of bimetallic catalyst Pd-Ti / TiO2:

[0051] In Example 1, the 3d metal salt was replaced with TiOSO4 instead of ScSO4, while the molar amount remained unchanged at 0.00017 mol; the rest was the same as in Example 1. The resulting catalyst was a Pd-Ti / TiO2 bimetallic catalyst.

[0052] Example 3: Preparation method of bimetallic catalyst Pd-V / TiO2:

[0053] In Example 1, the 3d metal salt was replaced with vanadium chloride instead of ScSO4, while the molar amount remained unchanged at 0.00017 mol; the rest was the same as in Example 1. The resulting catalyst was a Pd-V / TiO2 bimetallic catalyst.

[0054] Example 4: Preparation method of bimetallic catalyst Pd-Mn / TiO2:

[0055] In Example 1, the 3d metal salt was replaced with Mn(NO3)2 instead of ScSO4, while the molar amount remained unchanged at 0.00017 mol; the rest was the same as in Example 1. The resulting catalyst was a Pd-Mn / TiO2 bimetallic catalyst.

[0056] Example 5: Preparation method of bimetallic catalyst Pd-Fe / TiO2:

[0057] In Example 1, the 3d metal salt was replaced with Fe(NO3)2 instead of ScSO4, while the molar amount remained unchanged at 0.00017 mol; the rest was the same as in Example 1. The resulting catalyst was a Pd-Fe / TiO2 bimetallic catalyst.

[0058] Example 6: Preparation method of bimetallic catalyst Pd-Co / TiO2:

[0059] In Example 1, the 3d metal salt was replaced with Co(NO3)2 instead of ScSO4, while the molar amount remained unchanged at 0.00017 mol; the rest was the same as in Example 1. The resulting catalyst was a Pd-Co / TiO2 bimetallic catalyst.

[0060] Example 7: Preparation method of bimetallic catalyst Pd-Ni / TiO2:

[0061] In Example 1, the 3d metal salt was replaced with Ni(NO3)2 instead of ScSO4, while the molar amount remained unchanged at 0.00017 mol; the rest was the same as in Example 1. The resulting catalyst was a Pd-Ni / TiO2 bimetallic catalyst.

[0062] Example 8: Preparation method of bimetallic catalyst Pd-Cu / TiO2:

[0063] In Example 1, the 3d metal salt was replaced with Cu(NO3)2 instead of ScSO4, while the molar amount remained unchanged at 0.00017 mol; the rest was the same as in Example 1. The resulting catalyst was a Pd-Cu / TiO2 bimetallic catalyst.

[0064] Example 9: Preparation method of bimetallic catalyst Pd-Zn / TiO2:

[0065] In Example 1, the 3d metal salt was replaced with Zn(NO3)2 instead of ScSO4, while the molar amount remained unchanged at 0.00017 mol; the rest was the same as in Example 1. The resulting catalyst was a Pd-Zn / TiO2 bimetallic catalyst.

[0066] Example 1: A method for photocatalytic synthesis of diisopropylethylamine using a bimetallic catalyst, comprising the following steps:

[0067] 1) In a dark glass reactor, first purge with nitrogen to purge the atmosphere, then add 13 ml (0.09 mol) of diisopropylamine, 30 g (0.45 mol) of ethanol, and 50 mg of the Pd-Sc / TiO2 catalyst obtained in Example 1. Close the reactor lid. Continue purging with nitrogen (using a nitrogen balloon to provide the nitrogen atmosphere) until the pressure inside the glass reactor reaches 0.1 MPa. Irradiate with an 18W ultraviolet lamp (wavelength 365 nm, the ultraviolet lamp is parallel to the glass reactor wall, and the distance between the ultraviolet lamp and the glass reactor is about 5 cm). React under magnetic stirring (stirring speed 500-1000 rpm), controlling the reaction temperature at 20℃, and react for 10 hours.

[0068] 2) After the reaction is complete, the filter cake is obtained by vacuum filtration and is a recyclable bimetallic catalyst.

[0069] Sodium sulfate (approximately 0.05 g) was added to the filtrate and dried overnight. Unreacted ethanol was removed by rotary evaporation (40 °C), and diisopropylamine that may not have been completely reacted was also removed accordingly, yielding a crude product. The crude product was then distilled, and the fraction collected at 127.5–128.0 °C was used to obtain 8.5 g of N,N-diisopropylethylamine, with a yield of 73.2%. The structure of the obtained product was confirmed to be correct by comparison with the standard mass spectrum.

[0070] Example 2: A method for photocatalytic synthesis of diisopropylethylamine using a bimetallic catalyst, comprising the following steps:

[0071] 1) In a dark glass reactor, nitrogen gas was first introduced to purge the reactor. Then, 13 ml (0.09 mol) of diisopropylamine, 20 g (0.3 mol) of ethanol, and 100 mg of the Pd-Ti / TiO2 catalyst obtained in Example 2 were added. The reactor lid was then closed. Nitrogen gas was continued to be introduced until the pressure inside the glass reactor reached 0.1 MPa. The reactor was then irradiated with an 18W ultraviolet lamp and reacted under magnetic stirring at a controlled temperature of 20°C for 12 hours.

[0072] 2) Equivalent to step 2) of Example 1; 8.9 g of product N,N-diisopropylethylamine was obtained, with a yield of 76.7%. The structure of the obtained product was correct after comparison with the standard mass spectrum.

[0073] Example 3: A method for photocatalytic synthesis of diisopropylethylamine using a bimetallic catalyst, comprising the following steps:

[0074] 1) In a dark glass reactor, nitrogen gas was first introduced to purge the reactor. Then, 13 ml (0.09 mol) of diisopropylamine, 30 g (0.45 mol) of ethanol, and 45 mg of the Pd-V / TiO2 catalyst obtained in Example 3 were added. The reactor lid was then closed. Nitrogen gas was continued to be introduced until the pressure inside the glass reactor reached 0.12 MPa. The reactor was then irradiated with an 18W ultraviolet lamp and reacted under magnetic stirring at a controlled temperature of 25°C for 15 hours.

[0075] 2) Equivalent to step 2) of Example 1; 9.2g of product N,N-diisopropylethylamine was obtained, with a yield of 79.3%. The structure of the obtained product was correct after comparison with the standard mass spectrum.

[0076] Example 4: A method for photocatalytic synthesis of diisopropylethylamine using a bimetallic catalyst, comprising the following steps:

[0077] 1) In a dark glass reactor, nitrogen gas was first introduced to purge the reactor. Then, 13 ml (0.09 mol) of diisopropylamine, 30 g (0.45 mol) of ethanol, and 70 mg of the Pd-Sc / TiO2 catalyst obtained in Example 1 were added. The reactor lid was then closed. Nitrogen gas was continued to be introduced until the pressure inside the glass reactor reached 0.11 MPa. The reactor was then irradiated with an 18W ultraviolet lamp and reacted under magnetic stirring at a controlled temperature of 25°C for 20 hours.

[0078] 2) Equivalent to step 2) of Example 1; 9.3g of product N,N-diisopropylethylamine was obtained, with a yield of 80.1%. The structure of the obtained product was correct after comparison with the standard mass spectrum.

[0079] Example 5: A method for photocatalytic synthesis of diisopropylethylamine using a bimetallic catalyst, comprising the following steps:

[0080] 1) In a dark glass reactor, nitrogen gas was first introduced to purge the reactor. Then, 13 ml (0.09 mol) of diisopropylamine, 30 g (0.45 mol) of ethanol, and 100 mg of the Pd-Mn / TiO2 catalyst obtained in Example 4 were added. The reactor lid was then closed. Nitrogen gas was continued to be introduced until the pressure inside the glass reactor reached 0.13 MPa. The reactor was then irradiated with an 18W ultraviolet lamp and reacted under magnetic stirring at a controlled temperature of 35°C for 18 hours.

[0081] 2) Equivalent to step 2) of Example 1; 9.6 g of product N,N-diisopropylethylamine was obtained, with a yield of 82.7%. The structure of the obtained product was correct after comparison with the standard mass spectrum.

[0082] Example 6: A method for photocatalytic synthesis of diisopropylethylamine using a bimetallic catalyst, comprising the following steps:

[0083] 1) In a dark glass reactor, nitrogen gas was first introduced to purge the reactor. Then, 13 ml (0.09 mol) of diisopropylamine, 30 g (0.45 mol) of ethanol, and 50 mg of the Pd-Fe / TiO2 catalyst obtained in Example 5 were added. The reactor lid was then closed. Nitrogen gas was continued to be introduced until the pressure inside the glass reactor reached 0.11 MPa. The reactor was then irradiated with an 18W ultraviolet lamp and reacted under magnetic stirring at a controlled temperature of 25°C for 24 hours.

[0084] 2) Equivalent to step 2) of Example 1; 11g of product N,N-diisopropylethylamine was obtained, with a yield of 95.1%. The structure of the obtained product was correct after comparison with the standard mass spectrum.

[0085] Example 7: A method for photocatalytic synthesis of diisopropylethylamine using a bimetallic catalyst, comprising the following steps:

[0086] 1) In a dark glass reactor, first purge with nitrogen gas to purge the contents. Add 13 ml (0.09 mol) of diisopropylamine, 30 g (0.45 mol) of ethanol, and 120 mg of the Pd-Co / TiO2 catalyst obtained in Example 6. Close the reactor lid. Continue purging with nitrogen gas until the pressure inside the glass reactor reaches 0.1 MPa. Irradiate with an 18W ultraviolet lamp and react under magnetic stirring. Control the reaction temperature at 20°C and react for 24 hours.

[0087] 2) Equivalent to step 2) of Example 1; 9.3g of product N,N-diisopropylethylamine was obtained, with a yield of 80.1%. The structure of the obtained product was correct after comparison with the standard mass spectrum.

[0088] Example 8: A method for photocatalytic synthesis of diisopropylethylamine using a bimetallic catalyst, comprising the following steps:

[0089] 1) In a dark glass reactor, nitrogen gas was first introduced to purge the reactor. Then, 13 ml (0.09 mol) of diisopropylamine, 20 g (0.3 mol) of ethanol, and 150 mg of the Pd-Ni / TiO2 catalyst obtained in Example 7 were added. The reactor lid was then closed. Nitrogen gas was continued to be introduced until the pressure inside the glass reactor reached 0.1 MPa. The reactor was then irradiated with an 18 W ultraviolet lamp (wavelength 365 nm) and stirred magnetically. The reaction temperature was controlled at 20 °C, and the reaction was carried out for 15 hours.

[0090] 2) Equivalent to step 2) of Example 1; 10.1 g of product N,N-diisopropylethylamine was obtained, with a yield of 87%. The structure of the obtained product was correct after comparison with the standard mass spectrum.

[0091] Example 9: A method for photocatalytic synthesis of diisopropylethylamine using a bimetallic catalyst, comprising the following steps:

[0092] 1) In a dark glass reactor, nitrogen gas was first introduced to purge the reactor. Then, 13 ml (0.09 mol) of diisopropylamine, 40 g (0.6 mol) of ethanol, and 100 mg of the Pd-Cu / TiO2 catalyst obtained in Example 8 were added. The reactor lid was then closed. Nitrogen gas was continued to be introduced until the pressure inside the glass reactor reached 0.1 MPa. The reactor was then irradiated with an 18 W ultraviolet lamp (wavelength 365 nm) and reacted under magnetic stirring at a controlled temperature of 20 °C for 24 hours.

[0093] 2) Equivalent to step 2) of Example 1; 10.4 g of product N,N-diisopropylethylamine was obtained, with a yield of 90%. The structure of the obtained product was correct after comparison with the standard mass spectrum.

[0094] Example 10: A method for photocatalytic synthesis of diisopropylethylamine using a bimetallic catalyst, comprising the following steps:

[0095] 1) In a dark glass reactor, first purge with nitrogen gas to purge the reactor, then add 13 ml (0.09 mol) of diisopropylamine, 20 g (0.3 mol) of ethanol, and 150 mg of the Pd-Zn / TiO2 catalyst obtained in Example 9. Close the reactor lid. Continue purging with nitrogen gas until the pressure inside the glass reactor reaches 0.1 MPa. Irradiate with an 18W ultraviolet lamp, and under magnetic stirring, control the reaction temperature at 20°C for 24 hours.

[0096] 2) Equivalent to step 2) of Example 1; 8.3g of product N,N-diisopropylethylamine was obtained, with a yield of 71.5%. The structure of the obtained product was correct after comparison with the standard mass spectrum.

[0097] Example 11: Catalyst Recycling

[0098] The filter cake obtained by filtration in step 2) of Example 6 was washed three times with methanol and water alternately (to remove residual amine impurities attached to the filter cake), and then vacuum dried (dried at 50°C to constant weight); it was used as a catalyst for recycling.

[0099] New Pd-Fe / TiO2 was added to the recovered catalyst until the total weight was 50 mg, replacing the "50 mg of Pd-Fe / TiO2 catalyst" used in Example 6, with the rest remaining the same as in Example 6. The yield was 92%.

[0100] Comparative Example 1: The catalyst in Example 6 was changed from "Pd-Fe / TiO2" to Pd / TiO2 (the loading of Pd was the same), and the rest was the same as in Example 6. The result was: 6.5 g of N,N-diisopropylethylamine was obtained, with a yield of 56.2%.

[0101] Comparative Example 2: The molar amounts of PdCl2 and Fe(NO3)2 in Example 5 were changed as shown in Table 1 below. The rest remained the same as in Example 5. The catalyst obtained in this example replaced the Pd-Fe / TiO2 catalyst obtained in Example 5, with the amounts remaining unchanged at 50 mg. The rest was identical to Example 6. The yield of the obtained product is compared with that of Example 6 in Table 1 below.

[0102] Table 1

[0103]

[0104] Finally, it should be noted that the above examples are merely some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for photocatalytic synthesis of diisopropylethylamine using a bimetallic catalyst, characterized in that, Includes the following steps: 1) Under inert gas protection, diisopropylamine, ethanol, and a bimetallic catalyst are added to the reactor and the reaction is initiated under ultraviolet light irradiation. The molar ratio of ethanol to diisopropylamine is (2~10):

1. 45~150mg of bimetallic catalyst is used for every 0.09mol of diisopropylamine. The reaction temperature is 10~40℃, the reaction pressure is 0.1~0.5MPa, and the reaction time is 5~24 hours. 2) Filter the reaction product obtained in step 1). The filter cake is a recyclable bimetallic catalyst. Dry the filtrate and remove the unreacted ethanol by rotary evaporation to obtain crude diisopropylethylamine. 3) Distill the crude diisopropylethylamine, collecting the fraction at 127.5–128.0℃ to obtain diisopropylethylamine; The preparation method of the bimetallic catalyst is as follows: The Pd precursor and 3d metal salt were mixed and dissolved in deionized water, then mixed with the support, the pH was adjusted to 9-10, and the mixture was reduced. The mixture was then filtered, washed, and dried to obtain the bimetallic catalyst. The molar ratio of Pd precursor to 3d metal salt is 1:1; The Pd precursor is PdCl2 or Pd(NO)3, the 3d metal salt is a 3d metal nitrate or a 3d metal chloride, and the support is titanium dioxide; For every 0.00015~0.00019 mol of 3d metal salt, use 1g of carrier; The 3d metal is any one of the following: Sc, Ti, V, Mn, Fe, Co, Ni, Cu, Zn; Restore to any of the following methods: Method 1: Reduce by adding a reducing agent: For every 0.00015~0.00019 mol of 3d metal salt, use 0.1~0.2 g of reducing agent, reduce at 0~20℃, and reduce for 10~0.1 h; Method 2: Reduction under ultraviolet light for 2-24 hours.

2. The method according to claim 1, characterized in that: The activation reaction was carried out under magnetic stirring.

3. The method according to claim 2, characterized in that: The reducing agent is NaBH4, which is prepared into a NaBH4 solution with a concentration of 15~25g / L before use.

4. The method according to claim 3, characterized in that: The titanium dioxide is anatase, rutile, or amorphous.

5. The method according to claim 4, characterized in that: Each 0.00015~0.00019 mol of Pd precursor is prepared with 10 mL of deionized water.

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