Why does 2-(2-aminoethylamino)ethanol have superior CO2 separation performance to monoethanolamine? A computational study

Water-assisted absorption of CO2 by 3-amino-1-propanol: a mechanistic insight

The mechanism of the proton transfer in the reaction between CO2 and 3-amino-1-propanol with and without water molecules is investigated quantum-mechanically. Studies revealed that water molecules and the hydroxy group of 3-amino-1-propanol explicitly participate in the proton transfer, forming carbamic acid. It is found that water has a high impact on the energetics of CO2 absorption by reducing the barrier for proton transfer. Apart from the water molecules, the hydroxy group of alkanolamine significantly affects the energetics of the reaction. Five cases involving two, three, and four protons are discussed, and it is found that the proton transfer occurs in a concerted manner that depends on the initial configuration of the reaction complex. The present study unequivocally confirms the role of water molecules in the CO2 capturing via amine-based solvents.

Chemical similarity of dialkyl carbonates and carbon dioxide opens an avenue for novel greenhouse gas scavengers: cheap recycling and low volatility via experiments and simulations

Global warming linked to the industrial emissions of greenhouse gases may be the end of mankind unless it is adequately and timely handled. To prevent irreversible changes to the climate of the Earth, numerous research groups are striving to develop robust CO₂ sorbents. Dialkyl carbonates (DACs) and CO₂ exhibit obvious chemical similarities in their structure and properties. The degrees of oxidation of all atoms composing DACs and CO₂ are identical resulting in very similar nucleophilicities and electrophilicities of all interaction centers. While both compounds possess relatively high partial atomic charges on their polar moieties, the molecular geometries prevent tight binding of the head groups. The computed DAC-DAC binding energies are ∼40 kJ mol^-1, whereas the effect of the alkyl chain length is marginal. The phase transition points and shear viscosities of DACs are very low. We herein hypothesize and numerically rationalize that DACs represent noteworthy physical sorbents for CO₂ thanks to the similar sorbent-CO₂ and sorbent-sorbent interaction energies. By reporting in silico-derived sorption thermodynamics at various conditions, spectral and structural properties, and experimentally derived CO₂ capacities and recyclabilities, we highlight the mutual affinity of DACs and CO₂. Indeed, the experimentally determined CO₂ sorption capacity of 0.88 mol% (diethyl carbonate) at 278.15 K and 30 bar is competitive. The unprecedentedly low DAC-CO₂ binding energies, ∼14 kJ mol^-1, suggest a low-cost desorption process and outstanding recyclability of the sorbent. We also note that DACs possessing long alkyl chains (butyl, hexyl, octyl) exhibit negligible volatilities, while preserving the liquid aggregate state over a practically important temperature range. The reported results may foster the development of a new class of CO₂ scavengers with possibly quite peculiar characteristics.

Extensively amino-functionalized graphene captures carbon dioxide

Amino-functionalized graphene demonstrates certain potential to fix carbon dioxide.