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Kinetics of the reversible reaction of CO 2(aq) with taurate in aqueous solution
Author(s) -
Yu Hai,
Yang Nan,
Maeder Marcel,
Feron Paul
Publication year - 2018
Publication title -
greenhouse gases: science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.45
H-Index - 32
ISSN - 2152-3878
DOI - 10.1002/ghg.1771
Subject(s) - aqueous solution , chemistry , absorbance , reaction rate constant , spectrophotometry , reaction mechanism , reaction rate , equilibrium constant , chemical kinetics , base (topology) , kinetics , analytical chemistry (journal) , thermodynamics , inorganic chemistry , catalysis , chromatography , organic chemistry , mathematical analysis , physics , mathematics , quantum mechanics
Taurate has potential as an absorbent for CO 2 capture and is also an effective rate promoter in aqueous NH 3 ‐based absorbents. However, the detailed mechanism involved in the reaction of CO 2(aq) with taurate in aqueous solution is not available and the reaction rate and equilibrium constants for some reactions in the mechanism have not yet been determined. This limits our understanding of the role of taurate in the capture process using an NH 3 /taurate mixture and hinders rigorous rate‐based process simulation. In this work, we studied the reaction of taurate with CO 2 in aqueous solution with added acid‐base indicators at 288.0, 298.0, 308.0, and 318.0 K. Stopped‐flow spectrophotometry was used to record absorbance of the solutions, which reflects pH changes via colored acid‐base indicators as a function of time and over the wavelength range from 400.0–700.0 nm. Through global analysis of the kinetic data from the stopped flow reactor, we determined the temperature dependence of the rate and equilibrium constants using a detailed reaction scheme including all reactions in the taurate–CO 2 –H 2 O system. We then used stopped‐flow spectrophotometry to investigate the effect of taurate on the reaction of CO 2 in the mixed taurate−NH 3 −CO 2 −H 2 O system at 298.0 K. The mechanism for the reaction of the taurate and NH 3 mixture with CO 2(aq) was found to be a simple combination of two individual systems. Taurate in the mixture can significantly enhance the CO 2 absorption rate and NH 3 can work as a proton sink making more taurate available for CO 2 and the potential reduction of NH 3 loss. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd.