Kinetics and Mechanism of Carbamate Formation from CO₂(aq), Carbonate Species, and Monoethanolamine in Aqueous Solution

Abstract

Removal of carbon dioxide from fossil-based power generation is a potentially useful technique for the reduction of greenhouse gas emissions. Reversible interaction with aqueous amine solutions is most promising. In this process, the formation of carbamates is an important reaction of carbon dioxide. In this contribution, a detailed molecular reaction mechanism for the carbamate formation between MEA (monoethanolamine) and dissolved CO(2) as well as carbonate species in aqueous solution is presented. There are three parallel, reversible reactions of the free amine with CO(2), carbonic acid, and the bicarbonate ion; the relative importance of the three paths is strongly pH dependent. Kinetic and equilibrium measurements are based on (1)H NMR and stopped-flow measurements with rate constants, equilibrium constants, and protonation constants being reported.

Effects of Experimental Parameters on the Extraction of Silica and Carbonation of Blast Furnace Slag at Atmospheric Pressure in Low-Concentration Acetic Acid

“…This offers some advantages in that it contains a hydroxyl group that is protonated, in addition to an amine group. Actually, the protonation of the hydroxyl group of MEA has been observed as a result of the addition of acid [23]. The initial pH of the MEA solution was 12.5 and decreased as the loaded CO2 amount increased.…”

Kinetics of Carbon Dioxide with Amines. I. Stopped-Flow Studies in Aqueous Solutions. A Review

“…Kinetic parameters are optimized to reduce deviation between the model and experimental data. This kind of models is necessary when spectrophotometric detection is used to follow the reaction (Barth et al, 1981(Barth et al, , 1983(Barth et al, , 1984(Barth et al, , 1986 or if operating conditions like CO 2 loading is not compatible with an analytical solution of the model (Conway et al, , 2012McCann et al, 2009McCann et al, , 2011Wang et al, 2011;Xiang et al, 2012).…”

CO2 capture by pyrrolidine: Reaction mechanism and mass transfer

“…Also, the process footprint would decrease due to the reduction in energetic cost for absorption/regeneration cycles, because a minor liquid-phase volume must be treated. 15 Present work uses pyrrolidine aqueous solutions Additional Supporting Information may be found in the online version of this article.…”