McGuire Brett A, Martin-Drumel Marie-Aline, McCarthy Michael C
National Radio Astronomy Observatory , Charlottesville, Virginia 22903, United States.
Harvard-Smithsonian Center for Astrophysics and School of Engineering and Applied Sciences, Harvard University , Cambridge, Massachusetts 02138, United States.
J Phys Chem A. 2017 Aug 24;121(33):6283-6287. doi: 10.1021/acs.jpca.7b06103. Epub 2017 Aug 14.
Supercritical CO is an appealing nontoxic, environmentally friendly solvent for the industrial extraction of many classes of compounds, from caffeine to natural product drug precursors to petrochemical impurities. Apolar in isolation, the ability of supercritical CO to dissolve polar species has been empirically shown to be greatly enhanced by the addition of a small molar percentage of a polar cosolvent, often ethanol. Computational work predicts that the isolated ethanol-CO complex can exist either in an electron-donor configuration or through a hydrogen-bonding one; yet, neither has been previously experimentally observed. Here, we demonstrate by rotational spectroscopy that the isolated, gas-phase ethanol-CO dimer is an electron donor-acceptor complex.
超临界CO₂是一种具有吸引力的无毒、环境友好型溶剂，可用于从咖啡因到天然产物药物前体再到石化杂质等多种化合物的工业萃取。超临界CO₂单独存在时是非极性的，但通过添加小摩尔百分比的极性共溶剂（通常是乙醇），其实验结果表明它溶解极性物质的能力会大大增强。计算工作预测，孤立的乙醇 - CO₂络合物可以以电子供体构型或通过氢键构型存在；然而，此前尚未通过实验观察到这两种构型。在这里，我们通过旋转光谱证明，孤立的气相乙醇 - CO₂二聚体是一种电子供体 - 受体络合物。
