Different
thermodynamic properties of aqueous solutions of butyltriacetonediamine
(BuTAD), unloaded and loaded with carbon dioxide, are studied experimentally.
For unloaded mixtures of BuTAD and water, protonation equilibrium
constants between 283 and 333 K and liquid–liquid equilibria
between 313 and 353 K, including the lower critical point, are determined
at atmospheric pressure. Furthermore, the solubility of carbon dioxide
in aqueous solutions of BuTAD between 313 and 393 K is determined
at low loadings with an analytic method based on headspace gas chromatography
and at high loadings with a synthetic method using a high pressure
view cell. In the loaded system, solid precipitation, liquid–liquid
phase split, and the presence of metastable states are observed in
certain ranges. The data is interesting for assessing the aqueous
solution of BuTAD as solvent for carbon capture. A short-cut method
is used for comparing the new solvent with an aqueous solution of
monoethanolamine (MEA) with respect to the energy requirement of an
absorption/desorption process for CO2 scrubbing. Furthermore,
a new and simple gas chromatographic method for determining the loading
with carbon dioxide of aqueous solutions of amines is described.