Molecular motility and affinity of expanded carbon dioxide + ketone systems analyzed by molecular dynamics simulations

• Published in: Fluid phase equilibria Vol. 297; no. 2; pp. 172 - 177
• Main Authors: Aida, T., Aizawa, T., Kanakubo, M., Nanjo, H.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.10.2010; Elsevier
• Subjects: Agglomeration; Branched; Carbon; Carbon dioxide; Chemistry; Dissolution; Dynamical systems; Exact sciences and technology; Gas-expanded liquid; General and physical chemistry; Ketone; Ketones; MD simulation; Molecular dynamics; Simulation; Solution structure; Solutions; MD simulation; Gas-expanded liquid; Solution structure; Ketone; Carbon dioxide; Molecular dynamics method; Theoretical study; Molecular size; Transport process; Self diffusion; Gases; Binary mixture; Organic solvent; Molecular mobility; Expanded liquid; Radial distribution function; Affinity; Diffusion coefficient
• ISSN: 0378-3812; 1879-0224
• DOI: 10.1016/j.fluid.2010.05.007

We perform a molecular dynamics simulation for CO 2 + ketone mixtures to study the molecular motility and elucidate how CO 2 molecules are dissolved in a mixture. The self-diffusion coefficients increase with increasing CO 2 mole fraction ( x C O 2 ) and decreased with increasing molecular weight. These results mean that the mobility of molecules depends on the molecular size. To study molecular aggregation around CO 2 molecules, radial distribution functions (RDFs) and the distance from neighboring molecules to CO 2 molecules were calculated. The RDFs indicate that the CO 2 molecule exists near the carbonyl oxygen atom. Because of the distance of the neighboring molecule from the CO 2 molecule, the CO 2 molecule is less likely to exist around a branched alkyl ketone than a normal alkyl ketone.