Hydrogen bonding of single acetic acid with water molecules in dilute aqueous solutions  

作　　者：PU Liang SUN YueMing ZHANG ZhiBing 

机构地区：[1]School of Chemistry and Chemical Engineering,Southeast University,Nanjing 211189,China [2]Separation Engineering Research Center of Nanjing University,Key Laboratory in Meso-&Microscopic Chemistry of Ministry of Education of China,School of Chemistry and Chemical Engineering,Nanjing University,Nanjing 210093,China

出　　处：《Science China Chemistry》2009年第12期2219-2225,共7页中国科学（化学英文版）

基　　金：Supported by the Jiangsu Planned Projects for Postdoctoral Research Funds (No. 0901001C);the National Natural Science Foundation of China (Grant No. 20876072);the Natural Science Foundation of Jiangsu Province (No. KB2008023)

摘　　要：In separation processes,hydrogen bonding has a very significant effect on the efficiency of isolation of acetic acid (HOAc) from HOAc/H2O mixtures. This intermolecular interaction on aggregates composed of a single HOAc molecule and varying numbers of H2O molecules has been examined by using ab initio molecular dynamics simulations (AIMD) and quantum chemical calculations (QCC). Thermodynamic data in aqueous solution were obtained through the self-consistent reaction field calculations and the polarizable continuum model. The aggregation free energy of the aggregates in gas phase as well as in aqueous system shows that the 6-membered ring is the most favorable structure in both states. The relative stability of the ring structures inferred from the thermodynamic properties of the QCC is consistent with the ring distributions of the AIMD simulation. The study shows that in dilute aqueous solution of HOAc the more favorable molecular interaction is the hydrogen bonding between HOAc and H2O molecules,resulting in the separation of acetic acid from the HOAc/H2O mixtures with more difficulty than usual.In separation processes, hydrogen bonding has a very significant effect on the efficiency of isolation of acetic acid (HOAc) from HOAc/H2O mixtures. This intermolecular interaction on aggregates composed of a single HOAc molecule and varying numbers of H2O molecules has been examined by using ab initio molecular dynamics simulations (AIMD) and quantum chemical calculations (QCC). Thermodynamic data in aqueous solution were obtained through the self-consistent reaction field calculations and the polarizable continuum model. The aggregation free energy of the aggregates in gas phase as well as in aqueous system shows that the 6-membered ring is the most favorable structure in both states. The relative stability of the ring structures inferred from the thermodynamic properties of the QCC is consistent with the ring distributions of the AIMD simulation. The study shows that in dilute aqueous solution of HOAc the more favorable molecular interaction is the hydrogen bonding between HOAc and H2O molecules, resulting in the separation of acetic acid from the HOAc/H2O mixtures with more difficulty than usual.

关 键 词：acetic acid hydrogen BOND ab INITIO molecular dynamics free energy 

分 类 号：O623.611[理学—有机化学]