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Indexed by:期刊论文

Date of Publication:2014-02-26

Journal:INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH

Included Journals:SCIE、EI、Scopus

Volume:53

Issue:8

Page Number:3363-3372

ISSN No.:0888-5885

Abstract:A fundamental understanding on the inherent mechanisms leading to the different reactivity of the representative systems for unhindered and hindered families of amines, monoethanolamine (MEA) and 2-amino-2-methyl-1-propanol (AMP) in CO2 capture, is important for the rational design of novel amines. In this work, a comparative study on the reaction mechanisms between AMP + CO2 and MEA + CO2 was investigated at the B3LYP/6-311++G(d,p) level with the appropriate treatment of solvent effects. Two channels that lead to carbamate and bicarbonate were considered. The total reaction rate coefficients, were computed using a microkinetic model. The results indicate that the formation of bicarbonate for AMP + CO2 is more favorable in kinetics than the formation of carbamate. However, the case is reversed for MEA + CO2. This explains well the experimental. observation of different product distributions between the AMP + CO2 and MEA + CO2 reactions. The complementary results from QM/MM molecular dynamics simulations with umbrella sampling confirm the mechanistic difference between AMP + CO2 and MEA + CO2. In addition, it is found that the difference in electrostatic potential distribution between C-a of AMP and MEA is a possible reason leading to their different reaction mechanisms.