Improved Solvent Formulations for Efficient CO₂ Absorption and Low‐Temperature Desorption

Abstract

This experimental study describes efficient CO₂ capture by 2-amino-2-methyl-1-propanol (AMP)/piperazine (PZ) in ethylene glycol monoethyl ether (EGMEE, 2-ethoxyethanol) containing approximately 15 wt % of water. In these experiments, the solvent is continuously circulated between the absorber (packed-bed reactor at 30, 40, or 45 °C) and the desorber (at 80, 85, or 90 °C). The CO₂ -solvent reaction equilibria have been investigated by using ¹³C NMR spectroscopy, which provides confirmatory evidence that the formation of mono- and biscarbamate derivatives of PZ accounts for most of the CO₂ absorbed by the AMP/PZ/EGMEE/H₂O blend. The solid-state structures of AMP carbamate and of the carbonate salt of protonated AMP have been determined by using XRD. Both AMPCO₂(-) and CO(3)(2-) species completely convert to the monoalkyl carbonates on dissolving the respective salts in methanol, ethanol, or ethylene glycol.

Intermolecular interactions upon carbon dioxide capture in deep-eutectic solvents

“…CO 2 desorption in each step was achieved by heating the solution at 70 1C for 2 h under inert environment until complete desorption. 49,50 Contrary to the report where loss in mass of task-specific DES was noted, the initial mass of solvent was preserved after each desorption cycle in our study. 30 The stability of the [MEAÁCl][EDA] post consecutive absorption-desorption cycles was verified by 13 C NMR analysis (Fig.…”

Reversible Hydrophobic–Hydrophilic Transition of Ionic Liquids Driven by Carbon Dioxide

“…[2d, 14] Furthermore,t he two nitrogen atoms in [Im] À anion are equivalent, thus it may be expected that unsymmetrical monocarbamate [ImCO 2 ] À and symmetrical biscarbamate [Im(CO 2 ) 2 ] À can be formed at the same time. [15] The strong signal at 122.8 ppm was mainly assigned to the Im molecule,a nd the small shoulder at 122.7 ppm indicated the Scheme 1. [15] The strong signal at 122.8 ppm was mainly assigned to the Im molecule,a nd the small shoulder at 122.7 ppm indicated the Scheme 1.…”

“…Thes ignal at 161.8 ppm was ascribed to the carbon atoms of the carbonate and bicarbonate anions,w hich exchanged rapidly on the NMR timescale by proton scrambling,b ut the bicarbonate anion was predominant. [15] Therefore,acouple of low-field resonances was identified to be the carbonyl group of the monocarbamate [ImCO 2 ] À (165.8 ppm) and biscarbamate [Im(CO 2 ) 2 ] À (165.9 ppm) (Supporting Information, Table S5). [15] Therefore,acouple of low-field resonances was identified to be the carbonyl group of the monocarbamate [ImCO 2 ] À (165.8 ppm) and biscarbamate [Im(CO 2 ) 2 ] À (165.9 ppm) (Supporting Information, Table S5).…”

A comparative study of two polymorphs of bis(1-hydroxy-2-methylpropan-2-aminium) carbonate

“…This new polymorph was characterized by single-crystal X-ray diffraction analysis at low temperature (100 K). The salt crystallizes in the monoclinic system (space group C2/c, Z = 4), while a previously reported form of the same salt (denoted polymorph I) crystallizes in the triclinic system (space group P1, Z = 2) [Barzagli et al (2012). ChemSusChem, 5, 1724ChemSusChem, 5, -1731.…”

“…Alkanolamines, such as monoethanolamine, diethanolamine, methyldiethanolamine and 2-amino-2-methylpropan-1-ol, have been known for their high CO 2 absorption for over 60 years (Yang et al, 2008). They are used widely in the natural gas industry for industrial applications in reversible CO 2 capture during natural gas extraction and refining (Barzagli et al, 2012). In an attempt to crystallize a salt of (RS)-2-(3-benzoylphenyl)propionic acid with 2-amino-2-methylpropan-1-ol, we obtained instead a polymorph (denoted polymorph II) of ISSN 2053ISSN -2296 # 2016 International Union of Crystallography bis(1-hydroxy-2-methylpropan-2-aminium) carbonate, (I), suggesting that the amine group of the former compound captured CO 2 from the atmosphere forming the aminium carbonate salt.…”