CO₂‐Alkanolamine Reaction Kinetics: A Review of Recent Studies

Abstract

Alkanolamines are the most popular absorbents used to remove CO 2 from process gas streams. Therefore, the CO 2 reaction with alkanolamines is of considerable importance. The aim of this article is to provide an overview on the kinetics of the reaction of CO 2 with aqueous solutions of alkanolamines. The various reaction mechanisms that are used to interpret experimental kinetic data -zwitterion, termolecular and base-catalyzed hydration -are discussed in detail. Recently published data on reaction kinetics of individual amine systems and their mixtures are considered. In addition, the kinetic behavior of several novel aminebased solvents that have been proposed in the literature is analyzed. Generally, the reaction of CO 2 with primary, secondary and sterically hindered amines is governed by the zwitterion mechanism, whereas the reaction with tertiary amines is described by the base-catalyzed hydration of CO 2 .

Organic reactions for the electrochemical and photochemical production of chemical fuels from CO2 – The reduction chemistry of carboxylic acids and derivatives as bent CO2 surrogates

“…Carbon dioxide has been shown to react with amines [46][47][48] (Eq. (4), 26) and related derivatives to form carbamates (27).…”

Dynamic simulation of MEA absorption process for CO2 capture from power plants

“…The presence of the hydroxyl group (-OH) reduces the amine vapour pressure and increases its water solubility, while the amino group provides the necessary reactivity with acid gases to cause the absorption of acidic gases (Kohl and Nielsen, 1997). As shown in Figure The reaction meachanism and kinetics of the reaction between CO 2 and alkanolamines have been summarized and reviewed by several authors in the literature (Mahajani and Joshi, 1988;Versteeg et al 1996;Vaidya and Kenig, 2007). Amine-based CO 2 capture relies on the reaction of weak alkanolamine base with weak CO 2 acid gas to produce a water soluble salt.…”

“…Thus tertiary amines like MDEA are often blended with primary or secondary amines to reduce solvent regeneration costs (Vaidya and Kenig, 2007). In addition to this reaction, the following reactions may also occur in the case of aqueous solution, …”

“…A review of various reaction kinetics of this process is available in published literature (Blauwhoff et al, 1984;Versteeg et al, 1996;Aboudheir et al, 2003;Vaidya and Kenig, 2007). Zwitterion mechanism which describes the reaction between CO 2 and MEA via the formation of a zwitterions, (a locally ionic, net neutral molecule) followed by deprotonation is the most accepted kinetic model for absorption of CO 2 in aqueous MEA (Astarita, 1961;Clarke, 1964;Hikita et al, 1977;Danckwerts, 1979;Penny and Ritter, 1983;Alper, 1990 and its low rate of hydrolysis to bicarbonate (HCO 3 -).…”

PDU-Scale Experimental Results of CO2 Removal With Amp/Pz Solvent

“…One of the available options in the search for efficient solvents is using mixtures of amines of diversified properties. Primary and secondary amines are known for high reaction rate (Vaidya and Kenig, 2007), Tertiary amines, such as N-methyldiethanolamine (MDEA) display lower reaction energy compared to lower amines (Kim and Svendsen, 2007;Svensson et al, 2013). However, the CO 2 absorption process rate is far lower with tertiary amines (Wilk et al, 2013a).…”