Selective hydrogenation of phenol to cyclohexanone by SiO2-supported rhodium nanoparticles under mild conditions
A silica-supported rhodium catalyst for the selective hydrogenation of phenol to cyclohexanone under mild conditions has been developed. As the Rh concentration on the catalyst increased from 0.5 to 15 wt%, the conversion (at phenol/Rh mole ratio 100/1) dropped whereas the initial selectivity to cyc...
| Main Authors: | , , , , , , |
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| Other Authors: | |
| Format: | Journal Article |
| Language: | English |
| Published: |
2020
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| Subjects: | |
| Online Access: | https://hdl.handle.net/10356/142607 |
| _version_ | 1811683415175462912 |
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| author | Zhang, Hongwei Han, Aijuan Okumura, Kazu Zhong, Lixiang Li, Shuzhou Jaenicke, Stephan Chuah, Gaik-Khuan |
| author2 | School of Materials Science and Engineering |
| author_facet | School of Materials Science and Engineering Zhang, Hongwei Han, Aijuan Okumura, Kazu Zhong, Lixiang Li, Shuzhou Jaenicke, Stephan Chuah, Gaik-Khuan |
| author_sort | Zhang, Hongwei |
| collection | NTU |
| description | A silica-supported rhodium catalyst for the selective hydrogenation of phenol to cyclohexanone under mild conditions has been developed. As the Rh concentration on the catalyst increased from 0.5 to 15 wt%, the conversion (at phenol/Rh mole ratio 100/1) dropped whereas the initial selectivity to cyclohexanone increased. The direct hydrogenation to cyclohexanol occurred in parallel with partial hydrogenation to cyclohexanone. The negative correlation between selectivity and Rh dispersion suggests that direct hydrogenation occurs at low coordination sites whereas dissociation of phenol to phenoxy followed by hydrogenation to cyclohexanone takes place at higher coordinated terrace sites. DFT calculations revealed that the activation barrier for O–H bond cleavage is lower for phenol adsorbed on a Rh(1 1 1) flat surface than on small particles. By blocking the low coordination edge and step sites through grafting with (3-mercaptopropyl)trimethoxysilane, the cyclohexanone selectivity was improved from 82 to 93% at 100% conversion. The catalyst is active at room temperature and 1 atm H2 pressure and can be easily activated by in-situ reduction. |
| first_indexed | 2024-10-01T04:12:22Z |
| format | Journal Article |
| id | ntu-10356/142607 |
| institution | Nanyang Technological University |
| language | English |
| last_indexed | 2024-10-01T04:12:22Z |
| publishDate | 2020 |
| record_format | dspace |
| spelling | ntu-10356/1426072020-06-25T05:39:59Z Selective hydrogenation of phenol to cyclohexanone by SiO2-supported rhodium nanoparticles under mild conditions Zhang, Hongwei Han, Aijuan Okumura, Kazu Zhong, Lixiang Li, Shuzhou Jaenicke, Stephan Chuah, Gaik-Khuan School of Materials Science and Engineering Center for Programmable Materials Engineering::Materials Rhodium Phenol Hydrogenation A silica-supported rhodium catalyst for the selective hydrogenation of phenol to cyclohexanone under mild conditions has been developed. As the Rh concentration on the catalyst increased from 0.5 to 15 wt%, the conversion (at phenol/Rh mole ratio 100/1) dropped whereas the initial selectivity to cyclohexanone increased. The direct hydrogenation to cyclohexanol occurred in parallel with partial hydrogenation to cyclohexanone. The negative correlation between selectivity and Rh dispersion suggests that direct hydrogenation occurs at low coordination sites whereas dissociation of phenol to phenoxy followed by hydrogenation to cyclohexanone takes place at higher coordinated terrace sites. DFT calculations revealed that the activation barrier for O–H bond cleavage is lower for phenol adsorbed on a Rh(1 1 1) flat surface than on small particles. By blocking the low coordination edge and step sites through grafting with (3-mercaptopropyl)trimethoxysilane, the cyclohexanone selectivity was improved from 82 to 93% at 100% conversion. The catalyst is active at room temperature and 1 atm H2 pressure and can be easily activated by in-situ reduction. MOE (Min. of Education, S’pore) 2020-06-25T05:39:59Z 2020-06-25T05:39:59Z 2018 Journal Article Zhang, H., Han, A., Okumura, K., Zhong, L., Li, S., Jaenicke, S., & Chuah, G.-K. (2018). Selective hydrogenation of phenol to cyclohexanone by SiO2-supported rhodium nanoparticles under mild conditions. Journal of Catalysis, 364, 354-365. doi:10.1016/j.jcat.2018.06.002 0021-9517 https://hdl.handle.net/10356/142607 10.1016/j.jcat.2018.06.002 2-s2.0-85048826865 364 354 365 en Journal of Catalysis © 2018 Elsevier Inc. All rights reserved. |
| spellingShingle | Engineering::Materials Rhodium Phenol Hydrogenation Zhang, Hongwei Han, Aijuan Okumura, Kazu Zhong, Lixiang Li, Shuzhou Jaenicke, Stephan Chuah, Gaik-Khuan Selective hydrogenation of phenol to cyclohexanone by SiO2-supported rhodium nanoparticles under mild conditions |
| title | Selective hydrogenation of phenol to cyclohexanone by SiO2-supported rhodium nanoparticles under mild conditions |
| title_full | Selective hydrogenation of phenol to cyclohexanone by SiO2-supported rhodium nanoparticles under mild conditions |
| title_fullStr | Selective hydrogenation of phenol to cyclohexanone by SiO2-supported rhodium nanoparticles under mild conditions |
| title_full_unstemmed | Selective hydrogenation of phenol to cyclohexanone by SiO2-supported rhodium nanoparticles under mild conditions |
| title_short | Selective hydrogenation of phenol to cyclohexanone by SiO2-supported rhodium nanoparticles under mild conditions |
| title_sort | selective hydrogenation of phenol to cyclohexanone by sio2 supported rhodium nanoparticles under mild conditions |
| topic | Engineering::Materials Rhodium Phenol Hydrogenation |
| url | https://hdl.handle.net/10356/142607 |
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