Catalyst for hydroamination of ethanol as well as preparation method and application of catalyst

Abstract

The invention discloses a catalyst for hydroamination of ethanol and a preparation method and application thereof, the catalyst takes cobalt as a main active component and alumina particles as a carrier, and a Co / Al2O3 catalyst is prepared by an impregnation method. An auxiliary agent A is added in the dipping process to modify the catalyst. The catalyst provided by the invention has the characteristics of high activity, selectivity and the like in ethanol reductive amination reaction.

Description

Technical Field

[0001] This application relates to a catalyst for the hydroamylation of ethanol, its preparation method, and its application, belonging to the field of chemical catalyst preparation technology. Background Technology

[0002] Ethylamines are a class of organic compounds formed by replacing hydrogen atoms in ammonia molecules with ethyl groups. Based on the number of hydrogen atoms substituted, they can be mainly classified into monoethylamine, diethylamine, and triethylamine. They are all important fine chemical intermediates, widely used in pharmaceuticals, pesticides, rubber additives, metal beneficiation, and other fields.

[0003] Currently, there are three main routes for the synthesis of ethylamine: acetonitrile hydrogenation, ethane chloride ammonolysis, and ethanol reduction amination. Among these, ethanol reduction amination is increasingly valued by researchers in the field of industrial synthesis due to its advantages such as wide availability of raw materials, environmental friendliness, and high safety. Its reaction mechanism can be summarized as a "dehydrogenation-condensation-hydrogenation" process.

[0004] Chinese patent CN108212174A provides an ethylamine catalyst prepared by a mechanochemical method, but the preparation process of this catalyst is complex.

[0005] Chinese patent CN112044447A discloses a catalyst that uses alumina microspheres as a support. The active components include: (1) cobalt accounting for 10% to 40% of the total mass of the catalyst; (2) palladium accounting for 0.5% to 5% of the total mass of the catalyst; and (3) rhenium accounting for 0.1% to 1% of the total mass of the catalyst. The addition of precious metals to this catalyst increases the preparation cost; the reaction conditions are relatively harsh, with a reaction pressure of 2 MPa. Summary of the Invention

[0006] The purpose of this invention is to provide a catalyst for the hydroamination of ethanol, its preparation method, and its application. This catalyst maintains high activity and high selectivity in the ethanol amination reaction under relatively mild conditions.

[0007] According to a first aspect of this application, a catalyst for the hydroamination of ethanol is provided, the catalyst comprising an active component, an auxiliary agent, and a support; wherein the active component and the auxiliary agent are supported on the support. The active component is cobalt; the additives include rare earth elements; and the carrier is Al2O3 particles.

[0008] Optionally, the cobalt content, based on the weight percentage of the catalyst, is 1% to 30%; preferably 5% to 25%. Preferably, the content of the auxiliary agent is 0.1% to 2.0% by weight of the catalyst; more preferably 0.2% to 1.0%. Preferably, the rare earth element is selected from at least one of Ce, La, and Pr.

[0009] Optionally, the carrier particle size is 3-5 mm; the carrier is a spherical particle. Preferably, the specific surface area of ​​the carrier is >200 m². 2 ·g -1 pore volume > 0.4 cm 3 ·g -1 .

[0010] In this application, the Al2O3 content is >92%; XRF characterization showed that the alumina content was 99.547%, with a small amount of impurities.

[0011] According to a second aspect of this application, a method for preparing the above-mentioned catalyst is provided, the method comprising: The catalyst was obtained by impregnating Al2O3 particles in a mixed solution containing an active component precursor and an auxiliary precursor, followed by aging, drying, calcination, and reduction.

[0012] Optionally, the active component precursor is selected from at least one of cobalt nitrates and chlorides.

[0013] Optionally, the catalyst is prepared by vacuum equal-volume impregnation. Preferably, the soaking time is 2 to 5 hours.

[0014] Optionally, the aging temperature is 60~100℃. o C, aging time 1~5 h.

[0015] Optionally, the drying temperature is 60~120℃. o C, drying time 6~12 h; Preferably, the calcination temperature is 400~800℃. o C, roasting time 6~12 h; Optionally, the reduction includes: passing hydrogen gas through the calcined catalyst at a temperature of 200-600 °C. o The catalyst was obtained by reducing C for 5-15 h.

[0016] Preferably, the reduction temperature is 300~550℃. o C, reduction time 5~15 h.

[0017] According to a third aspect of this application, the use of the above-described catalyst in the amination of ethanol to produce ethylamine is provided.

[0018] Optionally, the reaction conditions for the application are: under hydrogen-containing conditions, a reaction pressure of 1.0~2.0 MPa, and a reaction temperature of 140~220°C. o C, the molar ratio of ethanol to ammonia is 6~1, and the liquid hourly space velocity is 0.1~1 h⁻¹. -1 .

[0019] Optionally, the catalyst can be used in the reaction of ethanol amination to ethylamine, and the reaction can be evaluated in a self-built fixed bed.

[0020] The beneficial effects that this application can produce include: The catalyst exhibits high activity and selectivity in the hydroamination of ethanol. Ethanol conversion is ≥90%, and ethylamine selectivity is ≥92%. Detailed Implementation

[0021] The present application is further illustrated below with reference to specific embodiments. The following descriptions are merely a few embodiments of the present application and are not intended to limit the present application in any way. Although the present application discloses preferred embodiments as follows, they are not intended to limit the present application. Any modifications or variations made by those skilled in the art without departing from the scope of the technical solution of the present application using the disclosed technical content are equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

[0022] Unless otherwise specified, the raw materials used in the embodiments of this application are all purchased commercially and used directly without any special treatment.

[0023] In the examples, the auxiliary agent A used was cerium nitrate, and the alumina parameters were: particle size 4 mm; specific surface area 313.9 m². 2 ·g -1 The pore volume is 0.45 cm. 3 ·g -1 .

[0024] Example 1 According to the content of active component and auxiliary component, 7.4 g of cobalt nitrate and 0.2 g of auxiliary agent A were weighed and dissolved in 2.03 g of water to prepare a solution. The alumina carrier was immersed in the solution for 2 hours, and then at 60°C... o C aging for 1 hour, 60 o Dry at C for 12 hours, 600 o Calcination at C for 3 hours, followed by the introduction of hydrogen gas at 550 °C o After C reduction for 7 h, the catalyst Cat-1 of this invention was obtained.

[0025] In this embodiment, the catalyst Cat-1 has a cobalt content of 15% and the additive A content is 0.5%.

[0026] Example 2 According to the content of active component and auxiliary component, 4.9 g of cobalt nitrate and 0.1 g of auxiliary agent A were weighed and dissolved in 3.22 g of water to prepare a solution. The alumina carrier was immersed in the solution for 2 hours, and then at 80°C... o C aging for 1 hour, 100 o Dry at C for 6 hours, 500 o Calcination at C for 3 hours, followed by the introduction of hydrogen gas at 500 °C o The catalyst Cat-2 of this invention was obtained by reducing C for 10 h.

[0027] In this embodiment, the catalyst Cat-2 has a cobalt content of 10% and the additive A content is 0.25%.

[0028] Example 3 According to the content of active component and auxiliary component, 9.9 g of cobalt nitrate and 0.3 g of auxiliary agent A were weighed and dissolved in 0.68 g of water to prepare a solution. The alumina carrier was immersed in the solution for 2 hours, and then at 80°C... o C aging for 1 hour, 120 o Dry at 700°C for 6 hours. o Calcination at C for 3 hours, followed by the introduction of hydrogen gas at 550 °C o The catalyst Cat-3 of this invention was obtained by reducing C for 10 h.

[0029] In this embodiment, the catalyst Cat-3 has a cobalt content of 20% and the additive A content is 1.0%.

[0030] Comparative Example 1 Catalyst Cat-4 was prepared in the same manner as in Example 1, except that no additive A was added and the cobalt content of the catalyst was 15%.

[0031] Comparative Example 2 Catalyst Cat-5 was prepared in the same manner as in Example 1, except that it was of alumina type (particle size 2 mm; specific surface area 128.1 m²). 2 ·g -1 The pore volume is 0.43 cm. 3 ·g -1 The catalyst has a cobalt content of 15%.

[0032] The catalysts provided in the various examples and comparative examples were used for the amination of ethanol to produce ethylamine at a reaction temperature of 200°C. o C. Reaction pressure 1.5 MPa, liquid hourly space velocity 0.5 h⁻¹ -1 The alcohol-to-amine ratio was 2, and the hydrogen-to-alcohol ratio was 5. The reaction products were analyzed online using an Agilent GC-8900 chromatograph with an FID detector and hydrogen as the carrier gas. The reaction performance is shown in Table 1. As can be seen from Table 1, the catalyst of this invention has high catalytic activity, effectively reduces the occurrence of side reactions, and thus improves the selectivity of ethylamine.

[0033] Table 1 Catalyst Evaluation Data

[0034] The embodiments described above are some, but not all, embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A catalyst for the hydroamination of ethanol, characterized in that, The catalyst comprises an active component, an auxiliary agent, and a support; the active component and the auxiliary agent are supported on the support. The active component is cobalt; the additives include rare earth elements; and the carrier is Al2O3 particles.

2. The catalyst according to claim 1, characterized in that, The cobalt content, by weight percentage of the catalyst, is 1% to 30%; preferably 5% to 25%. Preferably, the content of the auxiliary agent is 0.1% to 2.0% by weight of the catalyst; more preferably 0.2% to 1.0%. Preferably, the rare earth element is selected from at least one of Ce, La, and Pr.

3. The catalyst according to claim 1, characterized in that, The carrier has a particle size of 3-5 mm; the carrier is a spherical particle. Preferably, the specific surface area of ​​the carrier is > 200 m². 2 ·g -1 pore volume > 0.4 cm 3 ·g -1 .

4. A method for preparing the catalyst according to any one of claims 1 to 3, characterized in that, The preparation method includes: The catalyst was obtained by impregnating Al2O3 particles in a mixed solution containing an active component precursor and an auxiliary precursor, followed by aging, drying, calcination, and reduction.

5. The preparation method according to claim 4, characterized in that, The active component precursor is selected from at least one of cobalt nitrate and chloride.

6. The preparation method according to claim 4, characterized in that, The catalyst was prepared by vacuum equal-volume impregnation. Preferably, the soaking time is 2 to 5 hours.

7. The preparation method according to claim 4, characterized in that, The aging temperature is 60~100℃. o C, aging time 1~5 h.

8. The preparation method according to claim 4, characterized in that, The drying temperature is 60~120℃. o C, drying time 6~12 h; Preferably, the calcination temperature is 400~800℃. o C, roasting time 6~12 h; Preferably, the reduction temperature is 300~550℃. o C, reduction time 5~15 h.

9. Use of the catalyst according to any one of claims 1 to 3 in the production of ethylamine by ethanol amination.

10. The application according to claim 9, characterized in that, The reaction conditions for this application are: under hydrogen-containing conditions, a reaction pressure of 1.0~2.0 MPa, and a reaction temperature of 140~220°C. o C, the molar ratio of ethanol to ammonia is 6~1, and the liquid hourly space velocity is 0.1~1 h⁻¹. -1 .

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