Converting carbon dioxide into carbamato derivatives.

In order to improve the efficiency of the carbon dioxide cycling process and to reduce amine emissions, a series of nonvolatile amino acid salts with sterically hindered amine groups were investigated to determine their potential as direct replacements for monoethanolamine (MEA) in submarine-based CO2 scrubbers. Absorption from atmospheres containing various levels of CO2 was measured to assess the total capacities and absorption rates of amine solutions. The regeneration rates and extent of CO2 desorption were established by heating these solutions. 13C NMR spectroscopy was used to establish reaction products and solution compositions after both absorption and desorption. Methyl groups substituted adjacent to the amine were found to increase solution absorption capacities but with an overall reduction in absorption rate. Poor absorption rates at low CO2 levels and precipitation problems would prevent the α-dimethylamines examined from being used in existing submarine scrubbers. These amines, however, sho...

An Investigation of Some Sterically Hindered Amines as Potential Carbon Dioxide Scrubbing Compounds

https://pure.rug.nl/ws/files/14491789/2007Int.-J.-Greenh.-Gas-ControlSingh.pdf

Structure and activity relationships for amine based CO2 absorbents-I

In the garden of dispersion: High-accuracy ab initio calculations are performed to determine the nature of the interactions and the most favorable geometries between CO(2) and heteroaromatic molecules containing nitrogen (see figure). Dispersion forces play a key role in the stabilization of the dimer, because correlation effects represent about 50 % of the total interaction energy. The interactions between carbon dioxide and organic heterocyclic molecules containing nitrogen are studied by using high-accuracy ab initio methods. Various adsorption positions are examined for pyridine. The preferred configuration is an in-plane configuration. An electron donor-electron acceptor (EDA) mechanism between the carbon of CO(2) and the nitrogen of the heterocycle and weak hydrogen bonds stabilize the complex, with important contributions from dispersion and induction forces. Quantitative results of the binding energy of CO(2) to pyridine (C(5)H(5)N), pyrimidine, pyridazine, and pyrazine (C(4)H(4)N(2)), triazine (C(3)H(3)N(3)), imidazole (C(3)H(4)N(2)), tetrazole (CH(2)N(4)), purine (C(5)H(4)N(4)), imidazopyridine (C(6)H(5)N(3)), adenine (C(5)H(5)N(5)), and imidazopyridamine (C(6)H(6)N(4)) for the in-plane configuration are presented. For purine, three different binding sites are examined. An approximate coupled-cluster model including single and double excitations with a perturbative estimation of triple excitations (CCSD(T)) is used for benchmark calculations. The CCSD(T) basis-set limit is approximated from explicitly correlated second-order Moller-Plesset (MP2-F12) calculations in the aug-cc-pVTZ basis in conjunction with contributions from single, double, and triple excitations calculated at the CCSD(T)/6-311++G** level of theory. Extrapolations to the MP2 basis-set limit coincide with the MP2-F12 calculations. The results are interpreted in terms of electrostatic potential maps and electron density redistribution plots. The effectiveness of density functional theory with the empirical dispersion correction of Grimme (DFT-D) is also examined.

Ab initio Study of the Interactions between CO2 and N‐Containing Organic Heterocycles

Crystallization of a reaction product was observed during the absorption of CO2 in aqueous potassium taurate solutions at 298 K. The crystallizing solid was found to be the protonated amine. The critical CO2 loading value at which crystallization occurred was measured for various amino acid salt concentrations. A simple relation between the critical CO2 loading value, initial amino acid salt concentration, and solubility of the amino acid in water is established. This relation seems to hold well in predicting the critical CO2 loading value for salts of amino acids other than taurine, for which Hook (Ind. Eng. Chem. Res. 1997, 36, 1779) has recently published some qualitative experimental data. The influence of the formation of the solid reaction product during the absorption of CO2 in aqueous potassium taurate solutions on the mass-transfer characteristics of a gas−liquid contactor was investigated semiquantitatively for a stirred reactor. In particular, the effect of the presence and absence of crystals ...

/pdf/equilibrium-solubility-of-co2-in-aqueous-potassium-taurate-2n5gt9k7e7.pdf

Equilibrium Solubility of CO2 in Aqueous Potassium Taurate Solutions: Part 1. Crystallization in Carbon Dioxide Loaded Aqueous Salt Solutions of Amino Acids

Effet des substituants de l'atome de carbone en position α, sur les proprietes de donneur des amines primaires et aminoalcools

/pdf/molecular-orbital-approach-to-substituent-effects-in-amine-20t99x218i.pdf

J. R. Jun. Damewood

Papers

Molecular orbital approach to substituent effects in amine-CO2 interactions

Molecular structure of 1,8-bis(trimethylelement)naphthalenes

MO Approach to Substituent Effects in Amine-CO2 Interactions.

An ab initio investigation of rotation and inversion barriers in formylphosphine