A method for hydrodeoxygenation of amides

Abstract

The application discloses a method for amide hydrodeoxygenation. Under the catalysis of a multi-component metal oxide catalyst, amide and hydrogen gas are subjected to a hydrodeoxygenation reaction to generate corresponding amine compounds. The multi-component metal oxide catalyst is prepared by a coprecipitation method. Active components are copper oxide, zinc oxide, molybdenum trioxide, magnesium oxide and di-aluminum trioxide. The mass percentage ratio is 25-40:10-20:1-5:5-15:20-50 respectively. The method has simple reaction process, high reaction conversion rate and high selectivity. The catalyst preparation process is simple, and the method can be used for industrial production.

Description

Technical Field

[0001] This invention belongs to the field of catalytic reactions, specifically relating to a method for the hydrogenation and deoxygenation of amides. Background Technology

[0002] Amine compounds play a very important role in modern industry and are an important class of organic chemical products.

[0003] Cyclic imines play a crucial role in the chemical industry, such as tetrahydropyrrole, piperidine, and cyclohexylimine. Taking tetrahydropyrrole as an example, it has extremely wide applications in pharmaceuticals, food, pesticides, daily chemicals, coatings, textiles, printing and dyeing, papermaking, photosensitive materials, polymer materials, desulfurizers, and zeolite template agents. Currently, the main methods for producing tetrahydropyrrole include gas-phase catalytic synthesis using 1,4-butanediol as a raw material, gas-phase catalytic synthesis using tetrahydrofuran and ammonia as raw materials, gas-phase catalytic hydrogenation using pyrrolidone as a raw material, and gas-phase catalytic hydrogenation using pyrrole as a raw material. The process route for producing tetrahydropyrrole and its derivatives using pyrrolidone as a raw material has the advantages of low cost, no pollution, and a short process route, and has become a research focus in recent years.

[0004] Aliphatic amines, ranging from C2 to C16, also have important applications. They can be classified into primary, secondary, and tertiary amines. Currently, primary aliphatic amines are mostly produced by reacting the corresponding organic acid with ammonia to generate aliphatic nitrile, followed by hydrogenation. To prepare secondary or tertiary aliphatic amines, they can be obtained by alkylation of primary aliphatic amines.

[0005] Currently, there are few reports on the direct hydrogenation and deoxygenation of amides to prepare amines. Patent CN 109748801 A provides a method for the selective catalytic reduction of amides using nanoporous metals. The method involves adding an amide compound, a nanoporous metal catalyst, and a solvent to a reactor, adding the solvent and an organosilane, heating and stirring to prepare tertiary amines. In this invention, the catalyst is a relatively expensive nanoporous gold catalyst. Patent CN 109833871 A also uses a noble metal as one of the active components, disclosing an M1-M2-supported bifunctional catalyst for the selective hydrogenation of amides to prepare amines. The catalyst is obtained by impregnation. The M1 component is one or more of Ru, Rh, Pd, Ir, and Pt, and the M2 component is one or more of V, Mo, W, and Re. The support is mainly a common inorganic oxide or molecular sieve. Summary of the Invention

[0006] This invention provides a method for the hydrodeoxygenation of amides under the action of a multi-component metal oxide catalyst. The reaction process in this method is simple and easy to control, the catalyst is a non-precious metal, the cost is low, and the catalytic performance is excellent.

[0007] This invention provides a method for the hydrodeoxygenation of amides. Under the catalysis of a multi-component metal oxide catalyst, the amide reacts with hydrogen to generate the corresponding amine compound. The multi-component metal oxide catalyst is prepared by a co-precipitation method. The active components include copper oxide, zinc oxide, molybdenum trioxide, magnesium oxide, and aluminum oxide, with corresponding mass percentages of 25-40:10-20:1-5:5-15:20-50.

[0008] Furthermore, the preparation method of the multi-component metal oxide catalyst is as follows:

[0009] (1) Dissolve the required amounts of the soluble metal salts of copper oxide, zinc oxide, molybdenum trioxide, magnesium oxide and aluminum oxide with an equal mass of water to obtain a mixed solution;

[0010] (2) Add sodium carbonate solution dropwise to the mixed solution, with the final pH being 8-10;

[0011] (3) After the addition is complete, stir, filter, wash until sodium ions are less than 500 ppm, dry, calcine, and obtain the multi-component metal oxide catalyst.

[0012] Further, in step (1), the soluble metal salts corresponding to copper oxide, zinc oxide, molybdenum trioxide, magnesium oxide and aluminum oxide are copper nitrate trihydrate, zinc nitrate hexahydrate, ammonium molybdate tetrahydrate, magnesium nitrate hexahydrate and aluminum nitrate nonahydrate, respectively.

[0013] Furthermore, in step (2), the dropping temperature is 25–40°C, and the concentration of the sodium carbonate solution is 15–20 wt%.

[0014] Furthermore, in step (3), the stirring time is 0.5 to 2 hours, the drying temperature is 100 to 120°C, and the calcination temperature is 400 to 600°C.

[0015] Furthermore, the amide includes cyclic amides and C2-C2 amides. 16 Chain-like fatty amides.

[0016] Furthermore, the cyclic amide is one or more of 2-pyrrolidone, 2-piperidone, and caprolactam.

[0017] Furthermore, the C2 to C 16 The chain fatty amides are one or more of the following: linear fatty amides, N-methyl fatty amides, N,N-dimethyl fatty amides, N-ethyl fatty amides, and N,N-diethyl fatty amides.

[0018] Furthermore, in the hydrodeoxygenation reaction, the reaction temperature is 180-280℃; the reaction pressure is 0.5-5.0MPa.

[0019] Furthermore, the molar ratio of hydrogen to amide is 10–30.

[0020] Furthermore, the reaction is carried out in a fixed bed, with a mass hourly space velocity (WHSV) of 0.25–2 h⁻¹ for the amide feed. -1 .

[0021] Furthermore, the reaction uses one of tetrahydrofuran or water as a solvent. The solvent is mixed with the raw material amide and then fed into the mixture. The solvent accounts for 0-80 wt% of the mass fraction of the mixture.

[0022] Beneficial effects

[0023] (1) The amide hydrogenation deoxygenation method provided by the present invention uses multi-component metal oxides as active components. The reaction process is simple and easy to control. Compared with the prior art which uses noble metals as active components, the catalyst used in the present invention has low cost and excellent catalytic performance.

[0024] (2) The multi-component metal oxides of this application are prepared by co-precipitation, which further improves the catalytic activity compared with the mechanical mixing of multiple metal oxides. Detailed Implementation

[0025] The present invention will now be described through specific embodiments. Unless otherwise specified, all technical means used in the present invention are methods well known to those skilled in the art. Furthermore, the embodiments should be understood as illustrative, not limiting, of the scope of the invention; the essence and scope of the invention are defined only by the claims. For those skilled in the art, various changes or modifications to the material composition and dosage in these embodiments without departing from the essence and scope of the invention also fall within the protection scope of the present invention.

[0026] This invention provides a method for hydrogenating and deoxygenating an amide.

[0027] In one specific embodiment of the present invention, the method for hydrodeoxygenation of amide involves the amide reacting with hydrogen to generate the corresponding amine compound under the catalysis of a multi-component metal oxide catalyst. The multi-component metal oxide catalyst is prepared by a co-precipitation method, and the active components include copper oxide, zinc oxide, molybdenum trioxide, magnesium oxide, and aluminum oxide, with corresponding mass percentages of 25–40:10–20:1–5:5–15:20–50.

[0028] Taking 2-pyrrolidone, caprolactam, acetamide, N,N-dimethylacetamide, and N,N-dimethyldodecylamide as examples, the hydrogenation deoxygenation reaction formulas are as follows:

[0029]

[0030] The amide is selected from any commercially available reagent with a purity of not less than 98%; copper nitrate trihydrate, zinc nitrate hexahydrate, ammonium molybdate tetrahydrate, magnesium nitrate hexahydrate, aluminum nitrate nonahydrate, and sodium carbonate are selected from any commercially available reagent or industrial product with a purity of not less than 99%.

[0031] The reaction parameters for the preparation of corresponding amine compounds by the hydrogenation and deoxygenation of amides are the amide conversion (X) and the selectivity of the corresponding amine compound (S). The calculation methods for each reaction parameter are as follows:

[0032] Amide conversion rate X = (number of moles of amide reacted / total number of moles of amide) * 100%;

[0033] Amine selectivity S = (number of moles of amine compound produced in the reaction) / (number of moles of amide compound produced in the reaction) * 100%;

[0034] The content of each metal oxide in the catalyst was determined by X-ray fluorescence spectrometry (Panaco, X'AXIOS). mAX ) was measured.

[0035] Example 1

[0036] Catalyst preparation:

[0037] 118.5 g of copper nitrate trihydrate, 54.8 g of zinc nitrate hexahydrate, 2.5 g of ammonium molybdate tetrahydrate, 89.1 g of magnesium nitrate hexahydrate, and 220.7 g of aluminum nitrate nonahydrate were dissolved in an equal mass of water. A 20% sodium carbonate solution was added dropwise to the mixture at 30°C until the pH reached 8.9. After the addition was complete, the mixture was stirred for 1 hour, filtered, washed until sodium ions were less than 500 ppm, dried at 120°C, and calcined at 500°C. The catalyst was designated CAT-1.

[0038] reaction:

[0039] Catalyst CAT-1 was tableted and sieved into 20-40 mesh particles. 4g of catalyst was loaded into the middle section of a fixed-bed reaction tube, with inert quartz sand at both ends. The catalyst was first reduced at 300℃ for 6 hours, and then the reaction was carried out at 230℃ and 3.0 MPa. The mass hourly space velocity (WHSV) of the feedstock 2-pyrrolidone was 0.4 h⁻¹. -1 The solvent was tetrahydrofuran, with a solvent-to-2-pyrrolidone mass ratio of 1:1 and a hydrogen-to-2-pyrrolidone molar ratio of 20:1. After 48 hours of reaction, samples were taken and analyzed by gas chromatography. The conversion rate of 2-pyrrolidone in the reaction was 95.7%, and the selectivity of the product tetrahydropyrrolidone was 95.1%.

[0040] Example 2

[0041] Catalyst preparation: Same as in Example 1.

[0042] reaction:

[0043] Catalyst CAT-1 was tableted and sieved into 20-40 mesh particles. 4g of catalyst was loaded into the middle section of a fixed-bed reaction tube, with inert quartz sand at both ends. The catalyst was first reduced at 300℃ for 6 hours, and then the reaction was carried out at 220℃ and 2.0 MPa. The mass hourly space velocity (WHSV) of the feedstock 2-pyrrolidone was 0.4 h⁻¹. -1 The solvent was tetrahydrofuran, with a solvent-to-2-pyrrolidone mass ratio of 1:1 and a hydrogen-to-2-pyrrolidone molar ratio of 30:1. After 48 hours of reaction, samples were taken and analyzed by gas chromatography. The conversion rate of 2-pyrrolidone in the reaction was 93.3%, and the selectivity of the product tetrahydropyrrolidone was 96.5%.

[0044] Example 3

[0045] Catalyst preparation:

[0046] Dissolve 88.1 g of copper nitrate trihydrate, 54.8 g of zinc nitrate hexahydrate, 2.5 g of ammonium molybdate tetrahydrate, 89.1 g of magnesium nitrate hexahydrate, and 294.3 g of aluminum nitrate nonahydrate in an equal mass of water. Add a 20% sodium carbonate solution dropwise to the mixture at 30°C until the pH reaches 9.0. After the addition is complete, stir for 1 hour, filter, wash until sodium ion concentration is less than 500 ppm, dry at 120°C, and calcine at 500°C. The catalyst is designated CAT-3.

[0047] reaction:

[0048] The reaction process was the same as in Example 1, using CAT-3 as the catalyst. After 48 hours of reaction, samples were taken and analyzed by gas chromatography. The conversion rate of 2-pyrrolidone in the reaction was 96.8%, and the selectivity of tetrahydropyrrole for the product was 92.8%.

[0049] Example 4

[0050] Catalyst preparation: Same as in Example 1.

[0051] reaction:

[0052] The CAT-1 catalyst was tableted and sieved into 20-40 mesh particles. 4g of catalyst was loaded into the middle section of a fixed-bed reaction tube, with inert quartz sand at both ends. The catalyst was first reduced at 300℃ for 6 hours, and then the reaction was carried out at 220℃ and 1.0 MPa, with a mass hourly space velocity (WHSV) of 0.5 h⁻¹ for the caprolactam feedstock. -1 The solvent was tetrahydrofuran, with a solvent-to-caprolactam mass ratio of 7:3 and a hydrogen-to-caprolactam molar ratio of 20:1. After 48 hours of reaction, samples were taken and analyzed by gas chromatography. The conversion rate of caprolactam in the reaction was 99.2%, and the selectivity of the product cycloheximine was 97.6%.

[0053] Example 5

[0054] Catalyst preparation: Same as in Example 1.

[0055] reaction:

[0056] The CAT-1 catalyst was tableted and sieved into 20-40 mesh particles. 4g of catalyst was loaded into the middle section of a fixed-bed reaction tube, with inert quartz sand at both ends. The catalyst was first reduced at 300℃ for 6 hours, and then the reaction was carried out at 240℃ and 1.0 MPa. The mass hourly space velocity (WHSV) of the starting material, caprolactam, was 0.8 h⁻¹. -1 The solvent was tetrahydrofuran, with a solvent-to-caprolactam mass ratio of 7:3 and a hydrogen-to-caprolactam molar ratio of 20:1. After 48 hours of reaction, samples were taken and analyzed by gas chromatography. The conversion rate of caprolactam in the reaction was 99.5%, and the selectivity of the product cycloheximine was 96.3%.

[0057] Example 6

[0058] Catalyst preparation:

[0059] 106.3 g of copper nitrate trihydrate, 73.1 g of zinc nitrate hexahydrate, 1.2 g of ammonium molybdate tetrahydrate, 89.1 g of magnesium nitrate hexahydrate, and 220.7 g of aluminum nitrate nonahydrate were dissolved in an equal mass of water. A 20% sodium carbonate solution was added dropwise to the mixture at 30°C until the pH reached 9.0. After the addition was complete, the mixture was stirred for 1 hour, filtered, washed until sodium ions were less than 500 ppm, dried at 120°C, and calcined at 500°C. The catalyst was designated CAT-6.

[0060] reaction:

[0061] The reaction process was the same as in Example 4, using CAT-6 as the catalyst. After 48 hours of reaction, samples were taken and analyzed by gas chromatography. The conversion rate of caprolactam in the reaction was 98.4%, and the selectivity of the product cycloheximine was 97.5%.

[0062] Example 7

[0063] Catalyst preparation: Same as in Example 6.

[0064] reaction:

[0065] The CAT-6 catalyst was tableted and sieved into 20-40 mesh particles. 4g of catalyst was loaded into the middle section of a fixed-bed reaction tube, with inert quartz sand at both ends. The catalyst was first reduced at 300℃ for 6 hours, followed by a reaction at 200℃ and 1.0 MPa. The mass hourly space velocity (WHSV) of the acetamide feedstock was 0.8 h⁻¹, the solvent was water with a solvent-to-acetamide mass ratio of 1:2, and the molar ratio of hydrogen to acetamide was 30:1. After 48 hours of reaction, samples were taken and analyzed by gas chromatography. The acetamide conversion rate was 99.0%, and the selectivity of the ethylamine product was 96.9%.

[0066] Example 8

[0067] Catalyst preparation: Same as in Example 6.

[0068] reaction:

[0069] The CAT-6 catalyst was tableted and sieved into 20-40 mesh particles. 4g of the catalyst was loaded into the middle section of a fixed-bed reaction tube, with inert silica sand at both ends. The catalyst was first reduced at 300℃ for 6 hours, followed by a reaction at 200℃ and 1.0 MPa. The mass hourly space velocity (WHSV) of the feedstock N,N-dimethylacetamide was 0.8 h⁻¹, the solvent was water, and the mass ratio of solvent to N,N-dimethylacetamide was 1:4. The molar ratio of hydrogen to N,N-dimethylacetamide was 30:1. After 48 hours of reaction, samples were taken and analyzed by gas chromatography. The conversion rate of N,N-dimethylacetamide was 99.4%, and the selectivity of the product N,N-dimethylethylamine was 94.9%.

[0070] Example 9

[0071] Catalyst preparation: Same as in Example 1.

[0072] reaction:

[0073] The catalyst CAT-1 was tableted and sieved into 20-40 mesh particles. 4g of the catalyst was loaded into the middle section of a fixed-bed reaction tube, with inert quartz sand at both ends. The catalyst was first reduced at 300℃ for 6 hours, followed by a reaction at 240℃ and 3.0 MPa. The mass hourly space velocity (WHSV) of the feedstock N,N-dimethyldodecylamide was 0.4 h⁻¹, the solvent was tetrahydrofuran, and the mass ratio of solvent to N,N-dimethyldodecylamide was 4:1. The molar ratio of hydrogen to N,N-dimethyldodecylamide was 30:1. After 48 hours of reaction, samples were taken and analyzed by gas chromatography. The conversion rate of N,N-dimethyldodecylamide was 97.7%, and the selectivity of the product N,N-dimethyldodecylamine was 93.5%.

[0074] Example 10

[0075] Catalyst preparation:

[0076] 118.5 g of copper nitrate trihydrate, 69.4 g of zinc nitrate hexahydrate, 2.5 g of ammonium molybdate tetrahydrate, 63.6 g of magnesium nitrate hexahydrate, and 220.7 g of aluminum nitrate nonahydrate were dissolved in an equal mass of water. A 20% sodium carbonate solution was added dropwise to the mixture at 30°C until the pH reached 8.7. After the addition was complete, the mixture was stirred for 1 hour, filtered, and washed until the sodium ion concentration was less than 500 ppm. The mixture was then dried at 120°C and calcined at 500°C. The catalyst was designated CAT-10.

[0077] reaction:

[0078] The reaction process was the same as in Example 9, with CAT-10 as the catalyst. After 48 hours of reaction, samples were taken and analyzed by gas chromatography. The conversion rate of N,N-dimethyldodecylamide in the reaction was 97.1%, and the selectivity of the product N,N-dimethyldodecylamine was 95.2%.

[0079] Comparative Example 1

[0080] Catalyst preparation:

[0081] The catalyst, denoted as D-1, was obtained by mechanically mixing 39g of copper oxide, 15g of zinc oxide, 2g of molybdenum oxide, 14g of magnesium oxide, and 30g of aluminum oxide.

[0082] reaction:

[0083] The reaction process was the same as in Example 1, with catalyst D-1. After 48 hours of reaction, samples were taken and analyzed by gas chromatography. The conversion rate of 2-pyrrolidone in the reaction was 80.9%, and the selectivity of tetrahydropyrrole for the product was 86.6%.

[0084] Comparative Example 2

[0085] Catalyst preparation:

[0086] 118.5 g of copper nitrate trihydrate, 54.8 g of zinc nitrate hexahydrate, 2.5 g of ammonium molybdate tetrahydrate, and 323.7 g of aluminum nitrate nonahydrate were dissolved in an equal mass of water. A 20% sodium carbonate solution was added dropwise to the mixture at 30°C until the pH reached 9.0. After the addition was complete, the mixture was stirred for 1 hour, filtered, washed until sodium ion concentrations were less than 500 ppm, dried at 120°C, and calcined at 500°C. The catalyst was designated D-2.

[0087] reaction:

[0088] The reaction process was the same as in Example 1, with catalyst D-2. After 48 hours of reaction, samples were taken and analyzed by gas chromatography. The conversion rate of 2-pyrrolidone in the reaction was 97.1%, and the selectivity of tetrahydropyrrole for the product was 83.0%.

[0089] Comparative Example 3

[0090] Catalyst preparation:

[0091] 118.5 g of copper nitrate trihydrate, 54.8 g of zinc nitrate hexahydrate, 89.1 g of magnesium nitrate hexahydrate, and 235.5 g of aluminum nitrate nonahydrate were dissolved in an equal mass of water. A 20% sodium carbonate solution was added dropwise to the mixture at 30°C until the pH reached 9.0. After the addition was complete, the mixture was stirred for 1 hour, filtered, washed until sodium ion concentrations were less than 500 ppm, dried at 120°C, and calcined at 500°C. The catalyst was designated D-3.

[0092] reaction:

[0093] The reaction process was the same as in Example 1, with D-3 as the catalyst. After 48 hours of reaction, samples were taken and analyzed by gas chromatography. The conversion rate of 2-pyrrolidone in the reaction was 85.5%, and the selectivity of tetrahydropyrrole for the product was 90.4%.

[0094] Comparative Example 4

[0095] Catalyst preparation:

[0096] Dissolve 118.5 g of copper nitrate trihydrate, 2.5 g of ammonium molybdate tetrahydrate, 89.1 g of magnesium nitrate hexahydrate, and 360.5 g of aluminum nitrate nonahydrate in an equal mass of water. Add a 20% sodium carbonate solution dropwise to the mixture at 30°C until the pH reaches 8.9. After the addition is complete, stir for 1 hour, filter, wash until sodium ion concentration is less than 500 ppm, dry at 120°C, and calcine at 500°C. The catalyst is designated D-4.

[0097] reaction:

[0098] The reaction process was the same as in Example 4, with catalyst D-4. After 48 hours of reaction, samples were taken and analyzed by gas chromatography. The conversion rate of caprolactam in the reaction was 32.2%, and the selectivity of the product cycloheximine was 77.5%.

[0099] The above-described embodiments are merely illustrative of the technical concept and features of the present invention, intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for hydrogenating and deoxygenating an amide, characterized in that, Under the catalysis of a multi-component metal oxide catalyst, amides undergo a hydrodeoxygenation reaction with hydrogen to generate corresponding amine compounds; the multi-component metal oxide catalyst is composed of copper oxide, zinc oxide, molybdenum trioxide, magnesium oxide and aluminum oxide, with corresponding mass percentages of 25~40 : 10~20 : 1~5 : 5~15 : 20~50. The amides include cyclic amides and C2~C2 amides. 16 Chain-like fatty amides; The cyclic amide is one or more of 2-piperidinone and caprolactam; The C2~C 16 The chain fatty amide is one or more of linear fatty amide, N-methyl fatty amide, N,N-dimethyl fatty amide, N-ethyl fatty amide, and N,N-diethyl fatty amide; The multi-component metal oxide catalyst was prepared by a co-precipitation method; In the hydrogenation deoxygenation reaction, the reaction temperature is 180-280℃ and the reaction pressure is 0.5-5.0MPa.

2. The method according to claim 1, characterized in that, The multi-component metal oxide catalyst is obtained via a co-precipitation method as follows: (1) Dissolve the required amounts of the soluble metal salts of copper oxide, zinc oxide, molybdenum trioxide, magnesium oxide and aluminum oxide with an equal mass of water to obtain a mixed solution; (2) Add sodium carbonate solution dropwise to the mixed solution, with the final pH being 8-10; (3) After the addition is completed, stir, filter, and wash until the sodium ion concentration is less than 500 ppm, dry, and calcine to obtain the multi-component metal oxide catalyst.

3. The method according to claim 2, characterized in that, In step (1), the soluble metal salts corresponding to copper oxide, zinc oxide, molybdenum trioxide, magnesium oxide and aluminum oxide are copper nitrate trihydrate, zinc nitrate hexahydrate, ammonium molybdate tetrahydrate, magnesium nitrate hexahydrate and aluminum nitrate nonahydrate, respectively; in step (2), the dropping temperature is 25~40℃ and the concentration of sodium carbonate solution is 15-20wt%; in step (3), the stirring time is 0.5~2h, the drying temperature is 100~120℃ and the calcination temperature is 400~600℃.

4. The method according to claim 1, characterized in that, The molar ratio of hydrogen to amide is 10 to 30.

5. The method according to claim 1, characterized in that, The reaction is carried out in a fixed bed with a mass hourly space velocity (WHSV) of 0.25–2 h⁻¹ for the amide feed. -1 .

6. The method according to claim 1, characterized in that, The reaction uses one of tetrahydrofuran or water as a solvent. The solvent is mixed with the raw material amide and then fed into the mixture. The solvent accounts for 0 to 80 wt% of the mass fraction of the mixture.

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