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在醋酸/水体系的工业分离中,溶液中的氢键对分离效率有很大影响.本文采用两种第一性原理方法,即从头算分子动力学模拟(AIMD)和量子化学计算(QCC),对由单个醋酸和不同水分子所组成聚合体的氢键相互作用进行了研究,采用极化统一模型和自洽反应场模型计算得到了聚合体在水溶液中的热力学数据.从QCC计算的气相和水溶液中的聚合自由能表明六元环在两种状态下都为最优结构,热力学数据反映出的各种结构的相对稳定性与AIMD模拟的环分布符合得相当一致.研究表明,由于存在醋酸和水分子间的氢键作用,稀醋酸/水溶液中的醋酸分离要比在浓醋酸溶液中困难得多.
In the industrial separation of acetic acid / water system, the hydrogen bonding in solution has a great influence on the separation efficiency.In this paper, two first principles methods, ab initio molecular dynamics simulations (AIMD) and quantum chemical calculations (QCC) , The hydrogen bond interaction between polymers composed of a single acetic acid and different water molecules was studied and the thermodynamic data of the polymer in aqueous solution were calculated by using the polarization uniform model and the self-consistent reaction field model. And the free energy of the polymerization in aqueous solution show that the six-membered ring is the optimal structure in both states, and the relative stability of various structures reflected by the thermodynamic data is in good agreement with the ring distribution of the AIMD simulation.The study shows that due to the existence The hydrogen bonding between acetic acid and water molecules is much more difficult than acetic acid in dilute acetic acid / water solution than in concentrated acetic acid solution.