...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Physical chemistry chemical physics: PCCP >Solvation energies of the proton in methanol revisited and temperature effects
【24h】

Solvation energies of the proton in methanol revisited and temperature effects

机译：甲醇中质子的溶剂化能再致及温度效应

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

We report in this work the absolute solvation enthalpies and the absolute solvation free energies of the proton in methanol at temperatures ranging from 20 to 340 K and an extrapolation to a desired temperature. To achieve this, we thoroughly investigated the structures of neutral methanol clusters (MeOH)(n=2-10) and those of the protonated methanol decamer H+(MeOH)(n=10) at the M06-2X/6-31++g(d,p) level of theory. As a result, we noted that up to the octamer, the population of the neutral methanol clusters is constituted by cyclic isomers. For nonamers and decamers, both cyclic and branched cyclic isomers contribute to the population of the clusters. Moreover, folded or distorted cyclic isomers are the most favored at low temperatures, while higher temperatures favored the flat cyclic isomers for n = 7-9. For the methanol decamer, a branched cyclic isomer is found to be the most favored at low temperatures. Elsewhere, the infrared spectra of all the investigated structures are provided and compared against experiment. The binding energy of neutral methanol is calculated at the X/6-31++g(d,p) levels of theory, where X represents the DFT functionals M062X, APFD, MN15, B97XD and M08HX. It is observed that these functionals provide results in good agreement with the experimental vaporization enthalpy. However, the APFD functional shows the best performance followed by the other functionals in the order of M062X, MN15 and B97XD. Furthermore, the calculated solvation energies of the proton in methanol at these various levels of theory and at MP2/6-31++g(d,p) show that the B97XD functional shows the best performance in evaluating the solvation enthalpy and the solvation free energy of the proton in methanol and the calculated values are respectively -1140.5 kJ mol(-1) and -1100.7 kJ mol(-1) at room temperature. Elsewhere, we noted that the absolute solvation enthalpy of the proton in methanol is less affected by a change in temperature. However, the absolute solvation free energy of the proton in methanol remains constant only at temperatures lower than 180 K. For higher temperatures, the absolute solvation free energy of the proton in methanol increases as a linear function of the temperature and can be approximated by G(m)(H+,T) = 0.200T - 1161.4.
机译：我们在这项工作中报告了绝对的溶剂化焓和质子在甲醇的绝对溶剂化在20至340k的温度下的无水溶剂活化，以及到所需温度的外推。为此，我们彻底研究了M06-2X / 6-31 ++中性甲醇簇（MeOH）（MeOH）（N = 2-10）的中性甲醇簇（N = 2-10）的结构和质子化甲醇溶液H +（N = 10）的结构g（d，p）理论水平。结果，我们注意到，直到八寡，中性甲醇簇的群体由环状异构体构成。对于非美味和抗污膏，循环和支链的环状异构体均有助于簇的群体。此外，折叠或变形的环状异构体是低温最有利的，而较高的温度偏好的扁平环状异构体用于n = 7-9。对于甲醇溶解器，发现支化的环状异构体是低温下最有利的。在其他地方，提供所有研究结构的红外光谱并与实验进行比较。中性甲醇的结合能量在x / 6-31 ++ g（d，p）理论水平下计算，其中x表示DFT功能M062x，APFD，MN15，B97xD和M08HX。观察到这些功能与实验汽化焓吻合良好的结果。但是，APFD功能显示最佳性能，然后按M062X，MN15和B97XD的顺序进行其他功能。此外，在这些各种理论和MP2 / 6-31 ++ G（D，P）下，甲醇中质子的计算溶剂能量表明B97XD功能表明，评估溶剂化焓和溶剂的最佳性能在室温下，甲醇中质子的能量分别为-1140.5kJmol（-1）和-1100.7 kJ摩尔（-1）。在其他地方，我们注意到，甲醇中质子的绝对溶剂化焓受温度变化的影响较小。然而，甲醇中质子的绝对溶剂化自由能在低于180k的温度下恒定恒定。对于较高的温度，甲醇中质子的绝对溶剂化自由能随着温度的线性函数而增加，并且可以通过g近似（m）（h +，t）= 0.200t - 1161.4。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号