- Title
- Kinetics of the reversible reaction of CO2(aq) and HCO 3- with sarcosine salt in aqueous solution
- Creator
- Xiang, Qunyang; Fang, Mengxiang; Yu, Hai; Maeder, Marcel
- Relation
- Journal of Physical Chemistry: A Vol. 116, Issue 42, p. 10276-10284
- Publisher Link
- http://dx.doi.org/10.1021/jp305715q
- Publisher
- American Chemical Society
- Resource Type
- journal article
- Date
- 2012
- Description
- Aqueous sarcosine salts are fast carbon dioxide (CO²) absorbents suitable for use in postcombustion CO² capture in coal-fired power plants. We have developed a detailed reaction scheme including all the reactions in the sarcosine–CO²–water system. All unknown rate and equilibrium constants were obtained by global data fitting. We investigated the temperature-dependent rate and equilibrium constants of the reaction between aqueous CO² and sarcosine using stopped-flow spectrophotometry, by following the pH changes over the wavelength range 400–700 nm via coupling to pH indicators. The corresponding rate and equilibrium constants ranged from 15.0 to 45.0 °C and were analyzed in terms of Arrhenius, Eyring, and van’t Hoff relationships. The rate constant for the reaction between CO2 and sarcosine to form the carbamate at 25.0 °C is 18.6(6) × 10³ M⁻¹ s⁻¹, which is very high for an acyclic amine; its activation enthalpy is 59(1) kJ mol⁻¹ and the entropy is 33(4) J mol⁻¹ K⁻¹. In addition, we investigated the slow reaction between bicarbonate and sarcosine using 1H nuclear magnetic resonance spectroscopy and report the corresponding rate and equilibrium constants at 25.0 °C. This rate constant is 5.9 × 10⁻³ M⁻¹ s⁻¹.
- Subject
- carbon dioxide (CO²); aqueous sarcosine salts; coal-fired power plants
- Identifier
- http://hdl.handle.net/1959.13/1336900
- Identifier
- uon:27723
- Identifier
- ISSN:1089-5639
- Language
- eng
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