title: A computer simulation study on self- and cross-aggregation of multiple polar species in supercritical carbon dioxide.
abstract: The effect of hydrogen-bond cooperativity on self- and cross-aggregation of multiple polar species in supercritical carbon dioxide was investigated using both ab initio calculations and Monte Carlo simulations. Ab initio calculations indicate that hydrogen-bond cooperativity has a significant impact on the cluster size, but does not greatly influence the composition of clusters. The microscopic structures in the ethanol + CO(2) and acetic acid + CO(2) binary mixtures were first studied using Monte Carlo simulations with a strict set of criteria for hydrogen bonding, and a satisfactory agreement with experimental data was achieved. The state of microscopic phase separation in the ethanol + water + CO(2) and acetic acid + water + CO(2) ternary mixtures was then extensively investigated, indicating that the size and composition of aggregates are strongly dependent on the mixing ratio. Moreover, hydrogen-bond cooperativity must be considered to acquire more thorough understanding of the hydration process. On the basis of the detailed distributions of aggregate size and structure, a new two-staged hydration mechanism was finally proposed for the ternary solutions.
authors.affiliation: Department of Chemical Engineering, Tsinghua University, Beijing 100084, PR China.
authors.forename: Wenhao
authors.initials: W
authors.lastname: Xu
authors.forename: Jichu
authors.initials: J
authors.lastname: Yang
mesh_terms: D019342:Acetic Acid / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry*; D003198:Computer Simulation; D000431:Ethanol / Q000737:chemistry*; D006860:Hydrogen Bonding; D008956:Models, Chemical; D009010:Monte Carlo Method
chemical_list: D002245:Carbon Dioxide; D000431:Ethanol; D019342:Acetic Acid