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Qin Q, Liu H, Guo Y, Wang B, Zhu J, Ma J. Insights into the mechanism of the solvolysis of propylene oxide over titanium silicalite-1: a theoretical study. Phys Chem Chem Phys 2023; 25:21358-21375. [PMID: 37530074 DOI: 10.1039/d3cp01696j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/03/2023]
Abstract
In order to probe into the mechanism of solvolysis (alcoholysis/hydrolysis) of propylene oxide (PO), the formation of propylene glycol (PG), 1-methoxy-2-propanol (PPM) and 2-methoxy-1-propanol (SPM) over the TS-1 catalyst with tetrahedral Ti and Ti/defect sites was systematically discussed using an embedded quantum mechanical/molecular mechanics (QM/MM) approach. The results showed that the activity of PO solvolysis is closely related to the ring-opening ability of active substances, and the ring-opening ability is in the following order: Si-O(H)-Ti > Ti-OH > 5MR Ti-OOH > Ti-OCH3 (tetrahedral Ti site); 3MR Ti-OOH > Ti-OH > 5MR Ti-OOH > Ti-OCH3 (Ti/defect site). At the tetrahedral site, the concerted mechanism is the dominant pathway for PO ring opening to form PPM, while a competitive relationship exists between stepwise and concerted mechanisms to form PG and SPM. Si-O(H)-Ti exhibits excellent PO ring-opening activity because of its strong Brønsted acidity, but it is difficult to form. At the Ti/defect site, the stepwise mechanism via PO ring opening with 3MR Ti-OOH and then successive hydrolysis/alcoholysis to form product is the dominant pathway. The overall energy barrier of the optimal route is relatively lower as compared to the tetrahedral Ti site. This work opens up a new path for providing more information on the detailed mechanism in the solvolysis of PO over the TS-1 catalyst from a theoretical point of view.
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Affiliation(s)
- Qiaoyun Qin
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin University, No. 90, Weijin Road, Nankai District, Tianjin, 300072, China.
- Key Laboratory for Green Chemical Technology of Ministry of Education, R&D Center for Petrochemical Technology, Tianjin University, Tianjin 300072, China
| | - Hongxia Liu
- School of Chemistry and Chemical Engineering, Wuhan Textile University, Wuhan, 430200, China
| | - Yanke Guo
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin University, No. 90, Weijin Road, Nankai District, Tianjin, 300072, China.
- Key Laboratory for Green Chemical Technology of Ministry of Education, R&D Center for Petrochemical Technology, Tianjin University, Tianjin 300072, China
| | - Baohe Wang
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin University, No. 90, Weijin Road, Nankai District, Tianjin, 300072, China.
- Key Laboratory for Green Chemical Technology of Ministry of Education, R&D Center for Petrochemical Technology, Tianjin University, Tianjin 300072, China
| | - Jing Zhu
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin University, No. 90, Weijin Road, Nankai District, Tianjin, 300072, China.
- Key Laboratory for Green Chemical Technology of Ministry of Education, R&D Center for Petrochemical Technology, Tianjin University, Tianjin 300072, China
| | - Jing Ma
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin University, No. 90, Weijin Road, Nankai District, Tianjin, 300072, China.
- Key Laboratory for Green Chemical Technology of Ministry of Education, R&D Center for Petrochemical Technology, Tianjin University, Tianjin 300072, China
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Tao G, Yang H, He W, Jin S, Ge J, Liu W, Deng D, Chen Z, Yang W. Unusual pathway of epoxide hydration over a novel CoIII(salen)-based pseudohomogeneous catalyst with excellent performance. J Catal 2022. [DOI: 10.1016/j.jcat.2022.09.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Yang HQ, Chen ZX. Theoretical Studies on Bimetallic Salen Complexes Catalyzed Epoxide Hydration: Effects of Metal Centers, Substrates, and Ligands. J Phys Chem A 2021; 125:10155-10164. [PMID: 34793164 DOI: 10.1021/acs.jpca.1c07707] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
To provide guiding information for developing efficient and stable catalysts for epoxide hydration, we investigated the mechanism of propylene oxide (PO) to 1,2-propylene glycol (PG) using density functional theory (DFT) calculations. The mechanism was identified to follow the cooperative bimetallic mechanism in which a metal-salen complex activated H2O attacks the middle carbon atom of a metal-salen complex activated PO from the oxygen side of three-membered ring. Analyses reveal that the distortion energy correlates linearly with the barrier, and the hydrogen bonding between H2O and PO increases from reaction precursors to transition states. A nice linear relationship exists between the ratio of square root of ionic potential to the square of the distance from the metal ion spherical surface to the oxygen atom center of PO. It is demonstrated that the substrates with larger polarizability tend to have lower hydration barriers and the influence of ligands is less than that of metal centers and substrates. Modifying metal ions is the first choice for developing metal-salen catalysts, and metal ions with more formal charges and larger radius are expected to exhibit high activity. These findings shed lights on the mechanism and provide guiding information for developing efficient metal-salen catalysts for epoxide hydration.
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Affiliation(s)
- Hui-Qing Yang
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. China
| | - Zhao-Xu Chen
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry of MOE, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. China
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