Investigation of Different Organic Functional Groups Transformations in Laboratory-Simulated Hydrothermal Systems

The study of organic reactions within natural hydrothermal environments is significant for our understanding of the profound carbon and nitrogen cycles, the life dynamics of deep microbial populations, and possibly, lifes origins. Numerous reaction routes that involve organic compounds under geochemically pertinent hydrothermal conditions have been identified. However, the underlying mechanisms of these reactions, particularly those associated with inorganic substances, remain largely unexplored. This research aims to demystify these mechanisms to enable the development of predictive reactivity models and the investigation of potential applications of these reactions beyond the field of geochemistry. The focus of this dissertation is the mechanisms of interconversion of alcohols, aldehydes, amines with and without the presence of metal ions. Dehydration is always the primary 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. Inspired by the role of iron ions, we reported the first examples of oxidation of aldehydes with Fe(NO3)3 in water under anaerobic hydrothermal conditions in green and relatively clean way, with relatively high yields of carboxylic acids achieved within hours. A framework was investigated for selecting amines as geochemical tracers based on kinetic modeling. Even though the catalysis from minerals can be neglectable, the presence of metal ions altered the pathway by aerobic oxidation reaction. The geomimetic reactions discussed in this dissertation could potentially be employed in biomass oxidation to yield beneficial fuels and other high-value chemicals. Leveraging plentifully available metal ions and water as the solvent, these reactions offer a sustainable alternative to the existing biomass oxidation methods. The latter often involve the use of rare, exotic metal catalysts and organic solvents, presenting an environmental challenge. Thus, the exploration of these environmentally friendly reactions provides a greener approach to pollutants oxidation.