Ceria: multifunctional catalytic material in non-reductive CO2 conversion and H2-driven deoxydehydration
2024.09.23- Date
- 2024-10-10 16:00:00
- Department
- Graduate School of Carbon Neutrality
- Venue
- Online (Zoom Meeting)
- Speaker
- Prof. Keiichi Tomishige (Tohoku University)
Ceria is an essential component in the heterogeneous catalysis for non-reductive CO<sub>2</sub> conversion and rhenium-catalyzed deoxydehydration (DODH).
Ceria is an effective heterogeneous catalyst for the reactions such as alcohols+CO<sub>2</sub>, amines+CO<sub>2</sub>, and alcohols+amines+CO<sub>2</sub> which give corresponding organic carbonates [1], urea derivatives [2], and carbamates [3]. When the equilibrium limitation is severe [4], we have proposed the methods to break the limitation by the combination with the hydration of nitriles [5] and by H<sub>2</sub>O removal with gas stripping method [6]. Recently, we utilized the CO<sub>2</sub>-absorbed ethylenediamine (EDA-CA) as the reactant in the left figure, and its advantage is that pressurized CO<sub>2</sub> is not needed [7, 8].
DODH is the removal of vicinal OH groups to give carbon-carbon double bond, and it is more suitable to the synthesis of value-added chemicals from biomass because platform chemicals in the biomass refinery have OH groups [9]. It has been known that Re (VII) complexes catalyze DODH using PPh<sub>3</sub> and secondary alcohols as a reductant. Our target is to develop active heterogenous DODH catalysts using H<sub>2</sub> as a reductant. Our approach is the combination of high valent Re species fixed on oxides and noble metals with high H<sub>2</sub> activation ability for the development of heterogenous DODH catalysts enabling H<sub>2</sub> reductant. We reported that CeO<sub>2</sub> was much more effective support than other supporting materials such as carbon, SiO<sub>2</sub> and so on. A typical catalytic system is ReO<sub>x</sub>-Pd/CeO<sub>2</sub> [9], where DODH and subsequent hydrogenation can proceed and the saturated products were obtained. In order to obtain DODH products, a co-catalyst with high activation ability of H<sub>2</sub> and low catalytic activity in the hydrogenation of C=C. We found that ReO<sub>x</sub>-M/CeO<sub>2</sub> (M=Au, Ag) was effective as an effective heterogeneous DODH catalysts [10, 11], and the reaction mechanism is illustrated in the right figure.
<strong>References</strong>
[1] K. Tomishige, Y. Gu, M. Tamura, Y. Nakagawa, (2020), Mater. Today Sustain., 9, 100035.[2] M. Yabushita, R. Fujii, Y. Nakagawa, K. Tomishige, (2024), ChemCatChem, 16, e202301342.
[3] Y. Gu, A. Miura, M. Tamura, Y. Nakagawa, K. Tomishige, (2019), ACS Sustain. Chem. Eng., 7, 16795.
[4] K. Tomishige, Y. Gu, Y. Nakagawa, M. Tamura, (2020) Frontiers in Energy Research, 8, 117
[5] K. Tomishige, M. Tamura, Y. Nakagawa, (2019), Chem. Rec. 19, 1354.
[6] Y. Gu, M. Tamura, Y. Nakagawa, K. Nakao, K. Suzuki, K. Tomishige, (2021), Green Chem., 23, 5786.
[7] R. Fujii, M. Yabushita, D. Asada, M. Tamura, Y. Nakagawa, A. Takahashi, A. Nakayama, K. Tomishige, (2023), ACS Catal., 13, 1562.
[8] R. Fujii, M. Yabushita, Y. Li, Y. Nakagawa, K. Tomishige, (2023), ACS Catal., 13, 11041.
[9] N. Ota, M. Tamura, Y. Nakagawa, K. Okumura, K. Tomishige, (2015), Angew. Chem. Int. Ed., 54, 1897.
[10] S. Tazawa, N. Ota, M. Tamura, Y. Nakagawa, K. Okumura, K. Tomishige, (2016), ACS Catal. 6, 6393.
[11] K. Yamaguchi, J. Cao, M. Betchaku, Y. Nakagawa, M. Tamura, A. Nakayama, M. Yabushita, K. Tomishige, (2022), ChemSusChem, 15, e202102663.