二氧化硅介质对其表面水合笼稳定性的影响

The effect of medium silica on the stability of hydrated cages on its surface

采用量子化学中的密度泛函理论探究了不同笼型结构(CH4@51262和CH4@435663)的不同环面(四元环面、五元环面、六元环面)以不同方式(单面平行和双面插嵌)与介质Si O2作用对水合笼稳定性的影响,计算了水合笼与Si O2表面间的相互作用能、水合笼的变形能、水合笼中甲烷分子与笼子之间的相互作用能和水合笼中水分子间的结合能。结果表明:单面平行构型中的SH-6和双面插嵌构型中的SI-(5+6)、SH-(4+6)最有利于水合笼的分解;Si O2介质与水合笼通过结构匹配的方式形成氢键,降低了水合笼的稳定性,弱化了水合笼对甲烷的束缚。

This paper reports a study of the influence of the different torus（ four-membered ring,five-membered ring and six-membered ring） of different cage structures（ CH4@ 51262 and CH4@ 435663） interacting with medium silica in two modes of ways（ single ring parallel mode and double rings inserted mode） on the stability of hydrates,as investigated by density functional theory in quantum chemistry. Various energies were calculated,such as the interaction energy between the silica surface and cage,the deformation energy of the hydrate cage,the interaction energy between the methane molecule and the cage and the interaction energy between the water molecules within the cages. The results indicate that SH-6 in the single-sided parallel configuration and SI-（ 5 ＋ 6）,SH-（ 4 ＋ 6） in the double-sided interpolation configuration favor the decomposition of hydrates. A hydrogen bond can be formed between the silica surface and the cage because of structural matches,as a result the stability of the cage will be reduced and the binding ability of the cage to the methane molecule will be weakened.