A Computer Simulation Study on Self- and Cross-Aggregation of Multiple Polar Species in Supercritical Carbon Dioxide

作者：Xu, Wenhao; Yang, Jichu^*

来源：Journal of Physical Chemistry A, 2010, 114(16): 5414-5428.

DOI：10.1021/jp101092v

• MONTE-CARLO-SIMULATION
• HYDROGEN-BOND DYNAMICS
• AB-INITIO CALCULATIONS
• ULTRAFAST INFRARED-SPECTROSCOPY
• UNITED-ATOM DESCRIPTION
• ACETIC-ACID
• PHASE-EQUILIBRIA
• TRANSFERABLE POTENTIALS
• MOLECULAR SIMULATION
• RAMAN-SPECTROSCOPY

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 + CO2 and acetic acid + CO, 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 + CO2 and acetic acid + water + CO2 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.

• 出版日期2010-4-29
• 单位清华大学