Hydrothermal Transformations of Alcohols with Copper(II) and Iron(III) Salts
Hydrothermal Transformations of Alcohols with Copper(II) and Iron(III) Salts
复制标题
DOI：
10.1021/acsearthspacechem.1c00113
复制
发表时间：
2021-08-02
影响因子：
3.4
通讯作者：
Yang, Ziming
中科院分区：
文献类型：
--
作者：
Liao, Yiju;Aspin, Alexandria;Yang, Ziming
热液系统中的有机反应对于许多与地球化学有关的过程是重要和独特的，例如深海中的石油成熟和碳循环。提出了连接不同类型有机官能团的反应途径，并通过实验室模拟水热实验进行了验证。在这些有机官能团的相互转化中，醇作为氧化还原中间体连接深部沉积盆地中的碳氢化合物和羧酸。虽然在水热条件下(如200摄氏度以上)，醇的脱水形成碳氢化合物(如烯烃)在热力学上是有利的，但由于缺乏氧化能力，醇被氧化成醛和羧酸的可能性通常较小。在这项研究中，我们考察了六种不同的铜(II)和铁(III)盐对模型醇化合物水热反应的影响，包括伯醇、仲醇和叔醇。在没有溶解金属的情况下，我们发现在热液中醇的主要途径是脱水。然而，在铜(II)或铁(III)盐的存在下，醇的氧化被极大地促进，并成为竞争生成主要产物醛和羧酸的途径。对反应水溶液性质的地球化学计算进一步支持，在水热条件下，醇的氧化在热力学上对金属离子是有利的。我们的结果表明，溶解的金属离子在醇的水热转化中起着重要作用，这可能为理解无机材料如何控制自然水热环境中的有机转化提供新的理解。
Organic reactions in hydrothermal systems are important and unique for many geochemically relevant processes such as petroleum maturation and carbon cycling in the deep ocean. Reaction pathways that link different types of organic functional groups have been proposed and verified by laboratory-simulated hydrothermal experiments. In these organic functional group interconversions, alcohols serve as a redox intermediate that connects hydrocarbons and carboxylic acids in deep sedimentary basins. While dehydration of alcohols to form hydrocarbons such as alkenes is thermodynamically favorable under hydrothermal conditions (e.g., above 200 degrees C), oxidation of alcohols to aldehydes and carboxylic acids is often less likely to occur due to the lack of an oxidizing power. In this study, we examined the effects of six different copper(II) and iron(III) salts on hydrothermal reactions of model alcohol compounds, including primary, secondary, and tertiary alcohols. In the absence of dissolved metals, we find that dehydration is the dominant pathway for alcohols in the hydrothermal fluids. However, in the presence of copper(II) or iron(III) salts, the oxidation of alcohols is greatly promoted and becomes a competitive pathway to form aldehydes and carboxylic acids as the major products. Geochemical calculations on the aqueous properties of reactions further support that alcohol oxidations could be thermodynamically favorable with the metal ions under hydrothermal conditions. Our results suggest an important role of dissolved metal ions in hydrothermal transformations of alcohols, which may provide new understanding of how inorganic materials control organic transformations in natural hydrothermal environments.