Application of noble metal-loaded solid alkali bifunctional catalyst in selective preparation of trans-1, 4-cyclohexanediol
By using a precious metal-loaded solid base catalyst and utilizing the synergistic effect of the precious metal and the super-alkaline carrier, the problem of low selectivity of trans-1,4-cyclohexanediol in the existing technology is solved, and the effect of highly selective preparation of trans isomers is achieved.
Patent Information
- Application Number
- CN202510725526.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-03
- Publication Date
- 2025-09-09
AI Technical Summary
Existing catalysts have low selectivity for the trans isomer when hydroquinone is hydrogenated to produce 1,4-cyclohexanediol. Conventional catalysts such as Raney nickel, Ru/C, Pd/Al2O3, etc. produce too high a proportion of cis isomers, making it difficult to efficiently generate the trans isomer.
A γ-Al2O3 solid base catalyst loaded with precious metals Ru, Pd, and Rh is used to catalyze the hydrogenation of hydroquinone to prepare trans-1,4-cyclohexanediol through the synergistic effect of the precious metals and superalkaline potassium salts. The reaction conditions include calcination, reduction, and hydrogenation steps, and the reaction temperature and pressure are optimized.
Highly selective synthesis of trans-1,4-cyclohexanediol was achieved, with the selectivity of the trans isomer in the product being no less than 90%, making it suitable for large-scale production.
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Figure CN120607432A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of organic synthesis, and particularly relates to the application of a noble metal-supported solid base bifunctional catalyst in the selective preparation of trans-1,4-cyclohexanediol. Background Art
[0002] Trans-1,4-cyclohexanol (1,4-CHD) is a key intermediate in pharmaceuticals (such as anti-tumor and cardiovascular drugs) and high-performance polymers (such as heat-resistant engineering plastics). Currently, the main industrial synthesis method is the catalytic hydrogenation of hydroquinone. In the reaction of hydroquinone hydrogenation to produce 1,4-cyclohexanediol (1,4-CHD), existing catalysts such as conventional Raney nickel, Ru / C, and Pd / Al2O3 tend to generate the thermodynamically stable cis-isomer (cis-1,4-CHD accounts for >50%), while the trans-isomer (trans-1,4-CHD) is difficult to generate efficiently. Therefore, the development of highly selective catalyst systems that can control the ratio of isomers is of great industrial value. Summary of the Invention
[0003] In response to the problems existing in the prior art, the present invention aims to provide an application of a precious metal-loaded solid base bifunctional catalyst in the selective preparation of trans-1,4-cyclohexanediol. The catalyst uses one of the precious metals Ru, Pd, and Rh as the active metal and γ-Al2O3 loaded with one of KF, KNO3, K2CO3, and KHCO3 as the carrier. The catalyst can directly catalyze the hydrogenation of hydroquinone to highly selectively synthesize trans-1,4-cyclohexanediol (trans-1,4-CHD selectivity is not less than 90%).
[0004] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:
[0005] A noble metal-supported solid base bifunctional catalyst is used in the selective preparation of trans-1,4-cyclohexanediol, wherein the catalyst is used to catalyze the highly selective hydrogenation of hydroquinone to produce trans-1,4-cyclohexanediol.
[0006] The catalyst uses one of the noble metals Ru, Pd, and Rh as an active metal and γ-Al2O3 loaded with one of the potassium salts KF, KNO3, K2CO3, and KHCO3 as a carrier. The preparation process is as follows: the noble metal chloride, potassium salt, and the carrier are mixed, deionized water is added, and ball milling is performed to mix them evenly. After drying, the mixture is first calcined under an inert atmosphere and then reduced under a H2 atmosphere.
[0007] Furthermore, the mass ratio of the potassium salt to the carrier is 25-30%:70-75%; the noble metal in the noble metal chloride accounts for 0.5-5wt% of the total mass of the potassium salt and the carrier.
[0008] Furthermore, the inert atmosphere is nitrogen or argon atmosphere, the calcination temperature is 500-600° C., and the calcination time is 4-6 hours.
[0009] Furthermore, the reduction temperature is 200-300° C., and the reduction time is 2-3 hours.
[0010] Furthermore, the temperature of the hydrogenation reaction is 100-160° C., the hydrogen pressure is 1-5 MPa, and the solvent is one of tetrahydrofuran, 1,4-dioxane, cyclohexanol, and piperidine.
[0011] Beneficial effects of the present invention:
[0012] The present invention uses a noble metal-supported solid base bifunctional catalyst to catalyze the hydrogenation reaction of hydroquinone. Through the synergistic effect between the noble metal and the super-alkaline carrier, hydrogenation and isomerization can be simultaneously achieved, and trans-1,4-cyclohexanediol can be directly synthesized with high selectivity. The selectivity of trans-1,4-CHD in the 1,4-cyclohexanediol product after the reaction is not less than 90%, and the method is suitable for large-scale production of rich trans-1,4-cyclohexanediol. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 This is the chromatogram of the 1,4-cyclohexanediol product in Example 1.
[0014] Figure 2 This is the chromatogram of the 1,4-cyclohexanediol product in Example 2.
[0015] Figure 3 This is the chromatogram of the 1,4-cyclohexanediol product in Example 3.
[0016] Figure 4 This is the chromatogram of the 1,4-cyclohexanediol product in Comparative Example 1.
[0017] Figure 5 This is the chromatogram of the 1,4-cyclohexanediol product in Comparative Example 2.
[0018] Figure 6 This is the chromatogram of the 1,4-cyclohexanediol product in Comparative Example 3.
[0019] Figure 7 This is the chromatogram of the 1,4-cyclohexanediol product in Comparative Example 4.
[0020] Figure 8 This is the chromatogram of the 1,4-cyclohexanediol product in Comparative Example 5. DETAILED DESCRIPTION
[0021] The following is further described in conjunction with specific examples to make the technical solution of the present invention easier for those skilled in the art to understand. Unless otherwise specified, the raw materials used in the following examples are all commercially available conventional products.
[0022] Example 1
[0023] Preparation of catalyst:
[0024] Mix 0.62gRuCl3, 2.6gKF and 7.4gγ-Al2O3, then add appropriate amount of deionized water and mix by ball milling. After drying at 110℃, place it in a tube furnace, calcine at 600℃ for 5h under N2 protection, and then reduce it at 200℃ for 3h in H2 atmosphere.
[0025] Catalytic reaction:
[0026] Hydroquinone (10 mmol), catalyst (50 mg) and tetrahydrofuran (20 mL) were added to an autoclave, H2 was introduced to a pressure of 3 MPa, and the mixture was reacted at 140°C for 6 hours.
[0027] like Figure 1 As shown, after testing, cis-1,4-CHD accounted for 4.20% and trans-1,4-CHD accounted for 95.80% in the 1,4-cyclohexanediol product.
[0028] Example 2
[0029] Preparation of catalyst:
[0030] Mix 0.41gRuCl3, 2.6gKNO3 and 7.4gγ-Al2O3, then add appropriate amount of deionized water and mix by ball milling. After drying at 110℃, place it in a tube furnace, calcine at 600℃ for 5h under N2 protection, and then reduce it at 200℃ for 3h in H2 atmosphere.
[0031] Catalytic reaction:
[0032] Hydroquinone (10 mmol), catalyst (50 mg) and tetrahydrofuran (20 mL) were added to an autoclave, H2 was introduced to a pressure of 3 MPa, and the mixture was reacted at 140°C for 6 hours.
[0033] like Figure 2 As shown, after testing, cis-1,4-CHD accounted for 5.04% and trans-1,4-CHD accounted for 94.96% in the 1,4-cyclohexanediol product.
[0034] Example 3
[0035] Preparation of catalyst:
[0036] Mix 0.41gRuCl3, 2.6gK2CO3 and 7.4gγ-Al2O3, then add appropriate amount of deionized water and ball mill to mix evenly. After drying at 110℃, place it in a tube furnace, roast it at 500℃ for 5h under N2 protection, and then reduce it at 200℃ for 3h in H2 atmosphere.
[0037] Catalytic reaction:
[0038] Hydroquinone (10 mmol), catalyst (50 mg) and tetrahydrofuran (20 mL) were added to an autoclave, H2 was introduced to a pressure of 3 MPa, and the mixture was reacted at 140°C for 6 hours.
[0039] like Figure 3 As shown, after testing, cis-1,4-CHD accounted for 9.73% and trans-1,4-CHD accounted for 90.27% in the 1,4-cyclohexanediol product.
[0040] Comparative Example 1
[0041] The catalyst is Raney nickel;
[0042] Catalytic reaction:
[0043] Hydroquinone (10 mmol), catalyst (50 mg) and tetrahydrofuran (20 mL) were added to an autoclave, H2 was introduced to a pressure of 3 MPa, and the mixture was reacted at 140°C for 6 hours.
[0044] like Figure 4 As shown, after testing, cis-1,4-CHD accounted for 50.89% and trans-1,4-CHD accounted for 49.11% in the 1,4-cyclohexanediol product.
[0045] Comparative Example 2
[0046] The catalyst is Ru / C with a Ru loading of 3 wt%;
[0047] Catalytic reaction:
[0048] Hydroquinone (10 mmol), catalyst (50 mg) and tetrahydrofuran (20 mL) were added to an autoclave, H2 was introduced to a pressure of 3 MPa, and the mixture was reacted at 140°C for 6 hours.
[0049] like Figure 5 As shown, after testing, cis-1,4-CHD accounted for 50.44% and trans-1,4-CHD accounted for 49.56% in the 1,4-cyclohexanediol product.
[0050] Comparative Example 3
[0051] Preparation of catalyst:
[0052] Mix 0.62gRuCl3 with 10gγ-Al2O3, add appropriate amount of deionized water and mix thoroughly by ball milling. After drying at 110℃, place in a tube furnace and reduce at 200℃ for 3h in H2 atmosphere.
[0053] Catalytic reaction:
[0054] Hydroquinone (10 mmol), catalyst (50 mg) and tetrahydrofuran (20 mL) were added to an autoclave, H2 was introduced to a pressure of 3 MPa, and the mixture was reacted at 140°C for 6 hours.
[0055] like Figure 6 As shown, after testing, cis-1,4-CHD accounted for 44.88% and trans-1,4-CHD accounted for 55.12% in the 1,4-cyclohexanediol product.
[0056] Comparative Example 4
[0057] Preparation of catalyst:
[0058] Mix 0.62gRuCl3 with 10gMgO, add appropriate amount of deionized water and mix thoroughly by ball milling. After drying at 110℃, place in a tube furnace and reduce at 200℃ for 3h under H2 atmosphere.
[0059] Catalytic reaction:
[0060] Hydroquinone (10 mmol), catalyst (50 mg) and tetrahydrofuran (20 mL) were added to an autoclave, H2 was introduced to a pressure of 3 MPa, and the mixture was reacted at 140°C for 6 hours.
[0061] like Figure 7 As shown, after testing, cis-1,4-CHD accounted for 32.81% and trans-1,4-CHD accounted for 67.19% in the 1,4-cyclohexanediol product.
[0062] Comparative Example 5
[0063] Preparation of catalyst:
[0064] First, MgAl-LDH (magnesium aluminum hydrotalcite) was calcined at 600℃ for 2h to obtain Mg-Al oxide, then 0.62gRuCl3 was mixed with 10gMg-Al oxide, and then an appropriate amount of deionized water was added and ball milled to mix. After drying at 110℃, it was placed in a tubular furnace and reduced at 200℃ for 3h under H2 atmosphere.
[0065] Catalytic reaction:
[0066] Hydroquinone (10 mmol), catalyst (50 mg) and tetrahydrofuran (20 mL) were added to an autoclave, H2 was introduced to a pressure of 3 MPa, and the mixture was reacted at 140°C for 6 hours.
[0067] like Figure 8 As shown in the figure, after testing, cis-1,4-CHD accounted for 42.28% and trans-1,4-CHD accounted for 57.72% in the 1,4-cyclohexanediol product.
Claims
1. Use of a noble metal-supported solid base bifunctional catalyst in the selective preparation of trans-1,4-cyclohexanediol, characterized in that: The catalyst is used to catalyze the reaction of hydrogenating hydroquinone to prepare trans-1,4-cyclohexanediol with high selectivity; The catalyst uses one of the noble metals Ru, Pd, and Rh as an active metal and γ-Al2O3 loaded with one of the potassium salts KF, KNO3, K2CO3, and KHCO3 as a carrier. The preparation process is as follows: the noble metal chloride, potassium salt, and the carrier are mixed, deionized water is added, and ball milling is performed to mix them evenly. After drying, the mixture is first calcined under an inert atmosphere and then reduced under a H2 atmosphere.
2. The use according to claim 1, characterized in that: The mass ratio of the potassium salt to the carrier is 25-30%:70-75%; the noble metal in the noble metal chloride accounts for 0.5-5wt% of the total mass of the potassium salt and the carrier.
3. The use according to claim 1, characterized in that: The inert atmosphere is nitrogen or argon atmosphere, the calcination temperature is 500-600° C., and the calcination time is 4-6 hours.
4. The use according to claim 1, characterized in that: The reduction temperature is 200-300° C., and the reduction time is 2-3 hours.
5. The use according to any one of claims 1 to 4, characterized in that: The temperature of the hydrogenation reaction is 100-160° C., the hydrogen pressure is 1-5 MPa, and the solvent is one of tetrahydrofuran, 1,4-dioxane, cyclohexanol, and piperidine.