Thermodynamic property estimations for aqueous primary, secondary, and tertiary alkylamines, benzylamines, and their corresponding aminiums across temperature and pressure are validated by measurements from experiments

Robinson, Kirtland J.; Seewald, Jeffrey S.; Sylva, Sean P.; Fecteau, Kristopher M.; Shock, Everett L.

doi:10.1016/j.gca.2024.03.013

Cited by 1 publication

(1 citation statement)

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“…The equilibrium constants for abiotic synthesis reactions (Table A1) under bulk ocean and hydrothermal conditions were computed using the Deep Earth Water model (Sverjensky et al 2014), which is based on the revised Helgeson-Kirkham-Flowers (HKF) equation of state for aqueous species (Tanger & Helgeson 1988;Shock et al 1992). The internally consistent thermodynamic properties (G, H, S, C p , V, and HKF parameters) of organics come from previous studies (Shock & Helgeson 1990;Shock 1992;Schulte & Shock 1993;Plyasunov & Shock 2001;Plyasunov et al 2006;Robinson et al 2024) and are provided in Table A2.…”

Section: Reaction Affinity Calculations Using the Deep Earth Water Modelmentioning

confidence: 99%

The Potential for Organic Synthesis in the Ocean of Enceladus

Liu,

Xu,

Zhang

et al. 2024

ApJ

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The Cassini spacecraft detected a soup of organics in the plume of Saturn’s moon Enceladus. Those compounds could provide building blocks for the potential emergence or sustenance of microbial life in Enceladus’ subsurface ocean. However, the sources and stabilities of organics in Enceladus’ ocean are still poorly understood. Here, we perform nonequilibrium thermodynamic calculations to assess the energetics of abiotic synthesis for a broad spectrum of small organic molecules under both cold oceanic and hydrothermal conditions on Enceladus. Most of the organics that we studied are thermodynamically favorable to synthesize at micromolal dissolved concentrations over wide ranges of pH (8.5–11) and redox conditions. This suggests that many of the organic compounds detected by Cassini may be derived from reactions of CO2 and H2. However, some widely assumed precursors of biomolecules, such as formaldehyde, hydrogen cyanide, and acetylene, are found to be unstable and therefore unfavorable to be synthesized. We found that higher temperatures also seem to favor the synthesis of organic species under Enceladus hydrothermal conditions. Detection of thermodynamically unstable species in the plume might reflect artifacts introduced during high-speed spacecraft flybys and/or active synthesis via degradation of primordial chondritic organics, or biological activities.

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