The capture of carbonyl sulfide by N-methyldiethanolamine: A systematic density functional theory investigation |
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| Authors: | Jingwen Xue Rong-Zhen Liao Jinjin Li Yu-Chen Cao Ya-Qiong Zhang |
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| Institution: | 1. National Energy R&D Center of High-Sulfur Gas Exploitation, Research Institute of Natural Gas Technology, PetroChina Southwest Oil & Gasfield Company, Chengdu, China;2. Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, China |
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| Abstract: | In this contribution, the mechanism of carbonyl sulfide (COS) absorption by N-methyldiethanolamine (MDEA) aqueous solution was explored via theoretical computations. Detailed reaction mechanisms were analyzed using density functional theory (DFT) calculations at the B3LYP-D3 level of theory. In total, four different pathways for COS absorption by MDEA have been considered. The most favorable pathway for the removal of COS is a three-step mechanism including the hydrolysis, proton transfer, and dissociation of CO2, and hydrolysis is the rate-determining step. The mechanisms of the COS absorption by different amines were investigated, and the calculated results suggest that the total energy barrier for the COS absorption by MDEA is comparable to that by monoethanolamine (MEA), diethanolamine (DEA), and diisopropylamine (DIPA), indicating the COS absorption by all the four amines are feasible, while MDEA gives a better performance in terms of thermodynamics. |
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| Keywords: | carbonyl sulfide DFT calculations methyl diethanolamine reaction mechanism |
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