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Direct Conversion of Low-Concentration CO2 into N-Aryl and N-Alkyl Carbamic Acid Esters Using Tetramethyl Orthosilicate with Amidines as a CO2 Capture Agent and a Catalyst

Hiroki Koizumi, Katsuhiko Takeuchi*, Kazuhiro Matsumoto, Norihisa Fukaya, Kazuhiko Sato, Masahito Uchida, Seiji Matsumoto, Satoshi Hamura, Junya Hirota, Makoto Nakashige and Jun-Chul Choi*

*National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba 305-8565, Ibaraki, Japan, Email:,

H. Koizumi, K. Takeuchi, K. Matsumoto, N. Fukaya, K. Sato, M. Uchida, S. Matsumoto, S. Hamura, J. Hirota, M. Nakashige, J.-C. Choi, J. Org. Chem., 2023, 88, 5015-5024.

DOI: 10.1021/acs.joc.2c02326

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The use of Si(OMe)4 as a nonmetallic regenerable reagent and DBU as a CO2 capture agent and catalyst enables the direct conversion of low-concentration CO2 into carbamates. This reaction system does not require the addition of metal complex catalysts or metal salt additives. In addition, the method also works with exhaust gas containing impurities such as SO2, NO2, and CO or on a gram scale.

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proposed mechanism

Key Words

amination, carbamoylation

ID: J42-Y2023