He Zhongjin, Linga Praveen, Jiang Jianwen
Department of Chemical and Biomolecular Engineering, National University of Singapore, 117576, Singapore, Singapore.
Phys Chem Chem Phys. 2017 Jun 21;19(24):15657-15661. doi: 10.1039/c7cp01350g.
Microsecond molecular dynamics simulations were performed to provide molecular insights into the nucleation of CO hydrate. The adsorption of sufficient CO molecules around CO hydration shells is revealed to be crucial to effectively stabilize the hydrogen bonds formed therein, catalyzing the hydration shells into hydrate cages and inducing the nucleation. Moreover, a high aqueous CO concentration is found to be another key factor governing the nucleation of CO hydrate, and only above a critical concentration can the nucleation of CO hydrate occur. The 456 cages, with size similar to the CO hydration shell and an elliptical space closely matching a linear CO molecule, play a dominant role in initiating the nucleation and remain the most abundant. The incipient CO hydrate is rather amorphous due to the abundance of metastable cages (mostly 456).
进行了微秒级分子动力学模拟，以提供关于一氧化碳水合物成核的分子见解。研究发现，在一氧化碳水合壳周围吸附足够数量的一氧化碳分子对于有效稳定其中形成的氢键、促使水合壳转变为水合物笼并诱导成核至关重要。此外，高浓度的一氧化碳水溶液被发现是控制一氧化碳水合物成核的另一个关键因素，只有高于临界浓度时，一氧化碳水合物才能发生成核。456笼的尺寸与一氧化碳水合壳相似，其椭圆形空间与线性一氧化碳分子紧密匹配，在引发成核过程中起主导作用，并且数量最为丰富。由于存在大量亚稳笼（主要是456笼），初始的一氧化碳水合物相当无定形。
