Catalyst for preparing tetrahydrofuran through furan hydrogenation as well as preparation and application of catalyst

Abstract

The invention discloses a catalyst for preparing tetrahydrofuran through furan hydrogenation as well as preparation and application of the catalyst. According to the invention, the catalyst comprises a first metal component, a second metal component, an auxiliary agent and a carrier, the first metal component is nickel, the second metal component is copper, the auxiliary agent is cerium dioxide, and the carrier is silicon dioxide or aluminum oxide. Based on the mass percent of the catalyst, the catalyst comprises the following components in percentage by mass: 10-60% of Ni element, 1-20% of Cu element, 0.5-5% of cerium dioxide and the balance of a carrier. The catalyst is prepared by adopting a traditional impregnation method, the preparation method is simple, the required catalytic reaction condition is mild, the catalyst has the advantages of high catalytic activity and high tetrahydrofuran selectivity, and by adopting the catalyst, the yield of tetrahydrofuran prepared by furan hydrogenation can be improved, and the catalyst has a good industrial application prospect.

Description

Technical Field

[0001] The present invention relates to a catalyst for the hydrogenation of furan to tetrahydrofuran.

[0002] The present invention also relates to a preparation method of the above catalyst.

[0003] The present invention also relates to the application of the above catalyst in the reaction of hydrogenating furan to tetrahydrofuran. Technical Background

[0004] Tetrahydrofuran is an important chemical, mainly used for the production of PTMEG, the raw material of spandex. Due to its advantages such as low toxicity, low boiling point, good fluidity and good solubility, tetrahydrofuran is widely used as a solvent. At present, tetrahydrofuran is mainly obtained by dehydrating 1,4-butanediol industrially. Hydrogenating furan to prepare tetrahydrofuran is another production route.

[0005] U.S. Patent 2033292 discloses a method for preparing tetrahydrofuran by catalytic hydrogenation of furan using an iron-based catalyst under high temperature and high pressure conditions in a liquid phase system, and ethanol is required as a diluent during the reaction process. Korean Patent KR1020200022575 discloses a method for catalytic hydrogenation of furan to tetrahydrofuran using a Ru-Re bimetallic catalyst supported on biomass porous carbon, and the content of tetrahydrofuran in the product can reach about 70%. CN115445623A discloses a catalyst for continuous hydrogenation of furan to tetrahydrofuran, its preparation method and application. Using silica-supported alkaline earth metal-promoted nickel as a catalyst, furan is catalytically hydrogenated to tetrahydrofuran at 180-200 °C and a pressure of 2-10 MPa. The maximum selectivity of tetrahydrofuran is about 96%. After the catalyst runs for 240 hours, the amount of residual furan in the product increases from 1% to 6.9%, indicating that the catalyst has slow deactivation during operation. CN112547071A discloses a catalyst for hydrogenating furan to prepare tetrahydrofuran, its preparation method and application. Using a TiO 2 -Al 2 O 3 composite support-supported nickel catalyst, at 210 °C and a reaction pressure of 3 MPa, when the liquid volume space velocity of furan is 1 h -1 , and the hydrogen-oil molar ratio is 1000, the conversion rate of furan is 98.09%, and the selectivity of tetrahydrofuran is 92.01%.

[0006] The following one or more problems exist in the disclosed patents: use of noble metal catalysts, high reaction temperature, high reaction pressure, use of diluting solvents, poor stability, low selectivity for tetrahydrofuran, etc. In view of these problems, the present invention discloses a supported multi-component non-noble metal catalyst to achieve high-selectivity continuous hydrogenation of furan to tetrahydrofuran under mild reaction conditions. The catalyst can obtain a furan conversion rate higher than 99% and a tetrahydrofuran selectivity greater than 98% under the reaction conditions of 110 °C and 2 MPa, and the stability of the catalyst exceeds 600 hours. Summary of the Invention

[0007] 1. A catalyst for hydrogenating furan to tetrahydrofuran, the catalyst comprising a first metal component, a second metal component, a promoter, and a support, wherein the first metal component is nickel, the second metal component is copper, the promoter is cerium dioxide, and the support is silicon dioxide or aluminum oxide.

[0008] 2. In a preferred embodiment, the nickel content in the catalyst is 10-60% by mass of the catalyst, preferably 15-50%, more preferably 20-45%, and most preferably 30-40%; the copper content is 1-20% by mass of the catalyst, preferably 3-17%, more preferably 5-15%, and most preferably 8-10%; the cerium dioxide content is 0.5-5% by mass of the catalyst, preferably 1-4.5%, more preferably 1.5-4%, and most preferably 2-4%.

[0009] 3. Another aspect of the present invention is to provide a method for preparing the above-mentioned catalyst for hydrogenating furan to tetrahydrofuran, the method being a two-step impregnation method, which is specifically carried out according to the following steps:

[0010] a) Dissolve the precursors of the first part of nickel, copper, and cerium salts in deionized water or an organic solvent, and the amounts of nickel, copper, and cerium salts are 30%-70% of the theoretical metal salt requirement, and stir to mix them evenly to obtain a salt solution of the metal precursor.

[0011] b) Slowly add the silicon dioxide or alumina support to the above mixed salt solution and stir to mix evenly.

[0012] c) The sample obtained in step b is air-dried at room temperature for 4 to 96 hours, preferably 6 to 72 hours, more preferably 8 to 48 hours, and most preferably 12 to 24 hours; dried in an air atmosphere at a temperature of 323 to 423 K (preferably 333 to 413 K, more preferably 353 to 403 K, and most preferably 373 to 393 K) for 8 to 24 hours (preferably 8 to 20 hours, more preferably 10 to 18 hours, and most preferably 12 to 15 hours), and calcined at a temperature of 473 to 773 K (preferably 523 to 773 K, more preferably 573 to 773 K, and most preferably 623 to 723 K) for 2 to 48 hours (preferably 3 to 36 hours, more preferably 4 to 24 hours, and most preferably 4 to 12 hours), thereby obtaining a first precursor loaded with the active component oxide;

[0013] d) The precursors of the second part of nickel, copper, and cerium salts are dissolved in deionized water or an organic solvent. The amounts of nickel, copper, and cerium salts are the remaining part of the theoretical metal salt requirement minus the amount used in the first impregnation. Stir to mix them evenly to obtain a salt solution of the metal precursor;

[0014] e) The first precursor obtained in step c is slowly added to the above mixed salt solution and stirred to mix evenly.

[0015] f) The sample obtained in step c is air-dried at room temperature for 4 to 96 hours, preferably 6 to 72 hours, more preferably 8 to 48 hours, and most preferably 12 to 24 hours; dried in an air atmosphere at a temperature of 323 to 423 K (preferably 333 to 413 K, more preferably 353 to 403 K, and most preferably 373 to 393 K) for 8 to 24 hours (preferably 8 to 20 hours, more preferably 10 to 18 hours, and most preferably 12 to 15 hours), and calcined at a temperature of 473 to 773 K (preferably 523 to 773 K, more preferably 573 to 773 K, and most preferably 623 to 723 K) for 2 to 48 hours (preferably 3 to 36 hours, more preferably 4 to 24 hours, and most preferably 4 to 12 hours), thereby obtaining a catalyst loaded with the active component oxide;

[0016] g) The sample obtained in step f is subjected to an activation treatment to obtain a catalyst for the hydrogenation of furan to tetrahydrofuran.

[0017] 4. In a preferred embodiment, the activation conditions of the catalyst are carried out in a mixed atmosphere containing hydrogen. The hydrogen content in the hydrogen-containing mixed gas is 1 to 100%, and the other gases in the mixed gas except hydrogen are nitrogen, argon, or helium; the space velocity of the hydrogen-containing mixed gas is 500 to 10000 h -1 , preferably 700 to 8000 h -1 , more preferably 1000 to 6000 h -1 , most preferably 2000 to 4000 h -1, The activation temperature is 473K to 973K, preferably 523 to 873K, more preferably 573 to 773K, and most preferably 623 to 723K. The activation time is 1 to 100 hours, preferably 3 to 80 hours, more preferably 5 to 60 hours, and most preferably 12 to 48 hours. The activation pressure is 0.1 to 5.0MPa, preferably 0.1 to 4.0MPa, more preferably 0.1 to 3.0MPa, and most preferably 0.1 to 1.0MPa.

[0018] 5. In a preferred embodiment, the mass concentration of the salt in the mixed salt solution of step a) and step d) is 20% to 60%, preferably 25% to 55%, more preferably 30 to 50%, and most preferably 35% to 45%.

[0019] The nickel, copper, and cerium salts are nickel, copper, and cerium nitrates respectively.

[0020] 6. In a preferred embodiment, the activation of the catalyst is carried out by in vitro activation or in situ activation.

[0021] 7. In another aspect of the present invention, there is provided the use of the catalyst in the reaction of hydrogenating furan to tetrahydrofuran, and the said use is carried out under the following conditions: the reaction temperature is 323 to 473K, preferably 333 to 453K, more preferably 343 to 433K, and most preferably 363 to 413K. The reaction pressure is 0.1 to 6.0MPa, preferably 0.5 to 5.0MPa, more preferably 0.8 to 4.0MPa, and most preferably 1 to 3.0MPa. The space velocity is 0.01 to 6h -1 , preferably 0.1 to 5h -1 , more preferably 0.3 to 4h -1 , most preferably 0.5 to 3h -1 , and the molar ratio of hydrogen to furan is 4 to 400, preferably 10 to 300, more preferably 20 to 200, and most preferably 50 to 100.

[0022] 8. In a preferred embodiment, the reaction is carried out in a fixed bed reactor.

[0023] Using the catalyst of the present invention or the catalyst prepared by the preparation method of the present invention or the use of the present invention for hydrogenating furan to tetrahydrofuran, the furan conversion rate is higher than 99%, the tetrahydrofuran selectivity is higher than 98%, and the catalyst can stably operate for more than 600 hours.

[0024] This catalyst is prepared by the traditional impregnation method. The preparation method is simple, the required catalytic reaction conditions are mild, and it has the advantages of high catalytic activity and high tetrahydrofuran selectivity. Using the catalyst of the present invention can improve the yield of hydrogenating furan to tetrahydrofuran and has good industrial application prospects. Description of the Drawings

[0025] Figure 1 XRD pattern of the sample after the catalyst activation in Example 9

[0026] Figure 2 Stability of furan hydrogenation to tetrahydrofuran Detailed implementation manners

[0027] The present invention will be further described below through specific examples and comparative examples

[0028] Example 1

[0029] Preparation of the multi-component catalyst: 18.4 g of nickel nitrate hexahydrate, 3.5 g of copper nitrate trihydrate and 0.9 g of cerium nitrate hexahydrate were added to 13 g of deionized water, and dissolved under heating and stirring to obtain a clear solution. 10 g of γ-alumina support was added to the above solution, and it was air-dried at room temperature for 24 hours, dried at 120 °C for 12 hours, and calcined at 450 °C for 4 hours to obtain the precursor sample A. A was subjected to a second impregnation treatment using the same method. Specifically, 18.4 g of nickel nitrate hexahydrate, 3.5 g of copper nitrate trihydrate and 0.9 g of cerium nitrate hexahydrate were added to 13 g of deionized water, and dissolved under heating and stirring to obtain a clear solution. 10 g of precursor A was added to the above solution, allowed to stand at room temperature for 24 hours, dried at 120 °C for 12 hours, and calcined at 450 °C for 4 hours to obtain the catalyst B. The composition of the catalyst was 40Ni10Cu4CeO 2 / γ-Al 2 O 3 , where the mass content of Ni was 40%, the mass content of Cu was 10%, and the mass content of CeO 2 was 4%. The catalyst composition was the composition of the sample after hydrogen activation (the catalyst loading was 1 g, and after the catalyst was loaded, it was activated by hydrogen. The activation conditions were 400 °C, 0.1 MPa, and the hydrogen space velocity was 2000 h -1 , and the reduction treatment time was 20 hours).

[0030] Example 2

[0031] The composition of catalyst C was 35Ni10Cu4CeO 2 / γ-Al 2 O 3 . Except that in the first and second impregnation processes, 17.7 g of nickel nitrate hexahydrate, 3.9 g of copper nitrate trihydrate and 1.0 g of cerium nitrate hexahydrate were weighed, other steps (processes and conditions) were the same as in Example 1

[0032] Example 3

[0033] The composition of catalyst D was 30Ni10Cu4CeO 2 / γ-Al 2 O3 Except during the first and second impregnation processes, weigh 16.9 g of nickel nitrate hexahydrate, 4.3 g of copper nitrate trihydrate, and 1.1 g of cerium nitrate hexahydrate. Other steps (processes and conditions) are the same as in Example 1.

[0034] Example 4

[0035] The composition of catalyst E is 40Ni9Cu4CeO 2 / γ-Al 2 O 3 Except during the first and second impregnation processes, weigh 18.7 g of nickel nitrate hexahydrate, 3.2 g of copper nitrate trihydrate, and 0.9 g of cerium nitrate hexahydrate. Other steps (processes and conditions) are the same as in Example 1.

[0036] Example 5

[0037] The composition of catalyst F is 40Ni8Cu4CeO 2 / γ-Al 2 O 3 Except during the first and second impregnation processes, weigh 19 g of nickel nitrate hexahydrate, 2.9 g of copper nitrate trihydrate, and 1.0 g of cerium nitrate hexahydrate. Other steps (processes and conditions) are the same as in Example 1.

[0038] Example 6

[0039] The composition of catalyst G is 40Ni10Cu3CeO 2 / γ-Al 2 O 3 Except during the first and second impregnation processes, weigh 18.7 g of nickel nitrate hexahydrate, 3.6 g of copper nitrate trihydrate, and 0.7 g of cerium nitrate hexahydrate. Other steps (processes and conditions) are the same as in Example 1.

[0040] Example 7

[0041] The composition of catalyst H is 40Ni10Cu2CeO 2 / γ-Al 2 O 3 Except during the first and second impregnation processes, weigh 19 g of nickel nitrate hexahydrate, 3.6 g of copper nitrate trihydrate, and 0.5 g of cerium nitrate hexahydrate. Other steps (processes and conditions) are the same as in Example 1.

[0042] Example 8

[0043] The composition of catalyst K is 40Ni10Cu4CeO 2 / SiO 2 Except for using SiO 2 to replace γ-Al 2 O 3, Other steps (processes and conditions) are the same as in Example 1.

[0044] Example 9

[0045] The composition of catalyst M is 30Ni10Cu4CeO 2 / SiO 2 . Except for using SiO 2 to replace γ-Al 2 O 3 , Other steps (processes and conditions) are the same as in Example 3.

[0046] Comparative Example 1

[0047] Add 24.8 g of nickel nitrate hexahydrate to 11 g of deionized water, dissolve it to obtain a clear solution under heating and stirring, add 10 g of γ-alumina support to the above solution, dry it in the shade at room temperature for 24 hours, dry it at 120 °C for 12 hours, and calcine it at 450 °C for 4 hours to obtain the precursor sample P. Treat P with the same method for the second impregnation, specifically, add 4.8 g of nickel nitrate hexahydrate to 11 g of deionized water, dissolve it to obtain a clear solution under heating and stirring, add 10 g of precursor P to the above solution, let it stand at room temperature for 24 hours, dry it at 120 °C for 12 hours, and calcine it at 450 °C for 4 hours to obtain catalyst Q. The composition of the catalyst is 40Ni / γ-Al 2 O 3 , where the mass content of Ni is 40%.

[0048] Comparative Example 2

[0049] Add 19.8 g of nickel nitrate hexahydrate and 3.8 g of copper nitrate trihydrate to 11 g of deionized water, dissolve it to obtain a clear solution under heating and stirring, add 10 g of γ-alumina support to the above solution, dry it in the shade at room temperature for 24 hours, dry it at 120 °C for 12 hours, and calcine it at 450 °C for 4 hours to obtain the precursor sample R. Treat R with the same method for the second impregnation, specifically, add 19.8 g of nickel nitrate hexahydrate and 3.8 g of copper nitrate trihydrate to 11 g of deionized water, dissolve it to obtain a clear solution under heating and stirring, add 10 g of precursor P to the above solution, let it stand at room temperature for 24 hours, dry it at 120 °C for 12 hours, and calcine it at 450 °C for 4 hours to obtain catalyst S. The composition of the catalyst is 40Ni10Cu / γ-Al 2 O 3 , where the mass content of Ni is 30% and the mass content of Cu is 10%.

[0050] Comparative Example 3

[0051] 23 g of nickel nitrate hexahydrate and 0.9 g of cerium nitrate hexahydrate were added to 11 g of deionized water, and dissolved with heating and stirring to obtain a clear solution. 10 g of γ-alumina support was added to the above solution, air-dried at room temperature for 24 hours, dried at 120 °C for 12 hours, and calcined at 450 °C for 4 hours to obtain the precursor sample T. T was subjected to a second impregnation treatment using the same method, specifically, 23 g of nickel nitrate hexahydrate and 0.9 g of cerium nitrate hexahydrate were added to 11 g of deionized water, and dissolved with heating and stirring to obtain a clear solution. 10 g of the precursor T was added to the above solution, allowed to stand at room temperature for 24 hours, dried at 120 °C for 12 hours, and calcined at 450 °C for 4 hours to obtain the catalyst V. The composition of the catalyst was 40Ni3CeO 2 / γ-Al 2 O 3 where the mass content of Ni was 30%, and the mass content of CeO 2 was 3%.

[0052] The catalyst evaluation was carried out using a fixed-bed reactor with an inner diameter of 0.9 mm and a length of 420 mm. The catalyst loading was 1 g. After the catalyst was loaded, it was activated with hydrogen under the activation conditions of 400 °C, 0.1 MPa, and a hydrogen space velocity of 2000 h -1 , and the reduction treatment time was 20 hours. After activation, the temperature was reduced to the reaction temperature for reaction evaluation. The reaction temperature was 110 °C, the hydrogen pressure was 1 MPa, the mass space velocity of furan was 3 h -1 , and the molar ratio of hydrogen to furan was 60. The products were quantitatively analyzed by gas chromatography, and the results were the stable data after 96 hours of reaction. The evaluation results are listed in Table 1.

[0053] Table 1 Hydrogenation performance of different catalysts

[0054]

[0055] As can be seen from Table 1, by using the silica or alumina-supported nickel-copper-cerium dioxide multi-component non-noble metal catalyst of the present invention, the hydrogenation of furan can be catalyzed to prepare tetrahydrofuran with high activity and high selectivity, and the selectivity of tetrahydrofuran exceeds 98%. In addition, Figure 1 it can be seen that nickel in the activated sample of the catalyst of the present invention mainly exists in the form of nickel-copper alloy, and copper exists in the forms of metallic copper and nickel-copper alloy. As Figure 2 can be seen, the catalyst disclosed by the present invention has excellent stability. The catalyst has been operated for 600 hours without obvious performance degradation. Therefore, the catalyst provided by the present invention shows excellent activity, tetrahydrofuran selectivity and reaction stability in the reaction of hydrogenating furan to tetrahydrofuran. The present invention shows better performance than the existing published patents in terms of reaction conditions, activity, product selectivity and stability, and has an objective industrial application prospect.

[0056] The catalyst of Example 1 was evaluated for stability under the conditions of a reaction temperature of 110 °C, a hydrogen pressure of 1 MPa, a mass space velocity of furan of 1 h -1 , and a molar ratio of hydrogen to furan of 60. The evaluation results are as Figure 2 shown.

Claims

1. A catalyst for the hydrogenation of furan to tetrahydrofuran, characterized in that: the catalyst comprises a first metal component, a second metal component, a promoter and a support, wherein the first metal component is nickel, the second metal component is copper, the promoter is cerium dioxide, and the support is silica and / or alumina.

2. The catalyst according to claim 1, characterized in that: the nickel content in the catalyst is 10-60% by mass of the catalyst, preferably 15-50%, more preferably 20-45%, and most preferably 30-40%; the copper content is 1-20% by mass of the catalyst, preferably 3-17%, more preferably 5-15%, and most preferably 8-10%; the cerium dioxide content is 0.5-5% by mass of the catalyst, preferably 1-4.5%, more preferably 1.5-4%, and most preferably 2-4%.

3. A method for preparing the catalyst according to claim 1 or 2, characterized in that: the method is a two-step impregnation method, and specifically comprises the following steps: a) Dissolve the precursors of the first part of nickel, copper and cerium salts in water and / or an organic solvent, and the amounts of nickel, copper and cerium salts are 30%-70% of the theoretical metal salt requirement, stir to mix them evenly to obtain a mixed salt solution of metal precursors; b) Add the silica and / or alumina support to the mixed salt solution in step a) above, and stir to mix evenly; c) Dry the sample obtained in step b) in the shade at room temperature for 4-96 hours, preferably 6-72 hours, more preferably 8-48 hours, and most preferably 12-24 hours; dry in an air atmosphere at a temperature of 323-423 K (preferably 333-413 K, more preferably 353-403 K, most preferably 373-393 K) for 8-24 hours (preferably 8-20 hours, more preferably 10-18 hours, most preferably 12-15 hours), and calcine at a temperature of 473-773 K (preferably 523-773 K, more preferably 573-773 K, most preferably 623-723 K) for 2-48 hours (preferably 3-36 hours, more preferably 4-24 hours, most preferably 4-12 hours) to obtain a first precursor loaded with active component oxides; d) Dissolve the precursors of the second part of nickel, copper and cerium salts in water and / or an organic solvent, and the amounts of nickel, copper and cerium salts are the remaining part of the theoretical metal salt requirement minus the amount used in the first impregnation, stir to mix them evenly to obtain a mixed salt solution of metal precursors; e) Add the first precursor obtained in step c) to the mixed salt solution in step d) above, and stir to mix evenly; f) The sample obtained in step c) is air-dried at room temperature for 4 to 96 hours, preferably 6 to 72 hours, more preferably 8 to 48 hours, and most preferably 12 to 24 hours; dried in an air atmosphere at a temperature of 323 to 423 K (preferably 333 to 413 K, more preferably 353 to 403 K, most preferably 373 to 393 K) for 8 to 24 hours (preferably 8 to 20 hours, more preferably 10 to 18 hours, most preferably 12 to 15 hours), and calcined at a temperature of 473 to 773 K (preferably 523 to 773 K, more preferably 573 to 773 K, most preferably 623 to 723 K) for 2 to 48 hours (preferably 3 to 36 hours, more preferably 4 to 24 hours, most preferably 4 to 12 hours) to obtain a catalyst loaded with an active component oxide; g) The sample obtained in step f) is subjected to an activation treatment to obtain a catalyst for the hydrogenation of furan to tetrahydrofuran.

4. The method according to claim 3, characterized in that: Among them, the activation conditions of the catalyst are carried out in a mixed atmosphere containing hydrogen. The hydrogen content in the hydrogen-containing mixed gas is 1-100%, and the other gases in the mixed gas other than hydrogen are one or more of nitrogen, argon or helium; the space velocity of the hydrogen-containing mixed gas is 500-10000 h -1 , preferably 700-8000 h -1 , more preferably 1000-6000 h -1 , most preferably 2000-4000 h -1 , the activation temperature is 473K-973K, preferably 523-873K, more preferably 573-773K, most preferably 623-723K, the activation time is 1-100 hours, preferably 3-80 hours, more preferably 5-60 hours, most preferably 12-48 hours, and the activation pressure is 0.1-5.0 MPa, preferably 0.1-4.0 MPa, more preferably 0.1-3.0 MPa, most preferably 0.1-1.0 MPa.

5. The method according to claim 4, characterized in that: wherein the activation of the catalyst is carried out by in vitro activation or in situ activation.

6. The method according to claim 3, characterized in that: the mass concentration of the salts in the mixed salt solution in step a) and step d) is 20% to 60%, preferably 25% to 55%, more preferably 30 to 50%, and most preferably 35% to 45%. The nickel, copper, and cerium salts are nitrates of nickel, copper, and cerium, respectively.

7. Use of the catalyst according to claim 1 or 2 in the reaction for the hydrogenation of furan to tetrahydrofuran.

8. The use according to claim 7, characterized in that: The described method is carried out under the following conditions: the reaction temperature is 323 - 473K, preferably 333 - 453K, more preferably 343 - 433K, most preferably 363 - 413K; the reaction pressure is 0.1 - 6.0MPa, preferably 0.5 - 5.0MPa, more preferably 0.8 - 4.0MPa, most preferably 1 - 3.0MPa; the space velocity is 0.01 - 6h -1 , preferably 0.1 - 5h -1 , more preferably 0.3 - 4h -1 , most preferably 0.5 - 3h -1 , and the molar ratio of hydrogen to furan is 4 - 400, preferably 10 - 300, more preferably 20 - 200, most preferably 50 - 100.

9. The use according to claim 7 or 8, wherein the reaction is carried out in a fixed-bed reactor.

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