An experimental study of the thermolysis of hydrogen cyanide: the role of hydrothermal systems in chemical evolution

Abstract

<jats:title>Abstract</jats:title> <jats:p>Hydrogen cyanide (HCN) is considered a fundamental molecule in prebiotic chemistry experiments due to the fact that it could have an important role as raw material to form more complex molecules, as well as it could be an intermediate molecule in chemical reactions. However, the primitive scenarios in which this molecule might be available have been widely discussed. Hydrothermal systems have been considered as abiotic reactors and ideal niches for chemical evolution. Nevertheless, several experiments have shown that high temperatures and pressures could be adverse to the stability of organic molecules. Thus, it is necessary to carry out systematic experiments to study the synthesis, stability and fate of organic molecules in hydrothermal scenarios. In this work, we performed experiments focused on the stability and fate of HCN under a simple hydrothermal system scenario: the thermolysis of HCN at 100°C, at acidic and basic pH and in the presence of Mg-montmorillonite. Furthermore, we analysed the products from HCN thermolysis and highlighted the role of these chemical species as prebiotic molecules under a hydrothermal scenario.</jats:p>

A dual perspective on the microwave-assisted synthesis of HCN polymers towards the chemical evolution and design of functional materials

“…These satellites present active hydrothermalism, and HCN might be produced in these extraterrestrial oceans, taking its easy formation under analogous terrestrial hydrothermal conditions into account 47 . The potential presence of HCN in these moons may lead to a complex organic chemistry 51 , 52 .…”

A Lizardite–HCN Interaction Leading the Increasing of Molecular Complexity in an Alkaline Hydrothermal Scenario: Implications for Origin of Life Studies

“…Considering the role of minerals in HCN polymerization, previous reports have suggested that montmorillonite inhibits the formation of oligomers [ 47 , 56 ] and reduces the amount of carboxylic acids formed [ 58 ]. However, this does not mean that all mineral surfaces may have the same effect.…”

“…Recent papers have shown that hydrothermal fluids, during the serpentinization process, can lead to the occurrence of carbonaceous matter on mineral surfaces [ 42 , 43 , 44 ]. In addition, it has been shown that alkaline conditions and the dynamic surroundings that are present in hydrothermal systems are crucial for the transformation of cyanide species (e.g., cyanide salts and hydrogen cyanide, HCN) into other organic precursors with interesting roles in pre-RNA world scenarios [ 11 , 12 , 45 , 46 , 47 , 48 ]. Therefore, it seems necessary to study the role of serpentinite during the polymerization of HCN in order to simulate a feasible primitive geochemical scenario such as the surroundings of an alkaline hydrothermal system.…”

“…The polymerization of HCN has been widely studied [ 49 , 50 , 51 , 52 , 53 , 54 , 55 ]; however, few reports have focused on the polymerization of HCN onto mineral surfaces. Ferris et al [ 56 ] found that the presence of montmorillonite inhibits the formation of oligomers because the clay decomposes the tetramer of HCN (i.e., diaminomaleonitrile, DAMN); this effect increases at higher temperatures [ 47 ]. However, Boclair and coworkers [ 57 ] reported that layered double hydroxides (LDH) can favor the self-addition of cyanide at alkaline pH.…”

Submarine hydrothermal vent systems: the relevance of dynamic systems in chemical evolution and prebiotic chemistry experiments

“…Also, the interaction among minerals (olivine and orthopyroxene) with amino acids during several days (147 days) at 200 bar with periodic thermal cycling (30-100°C) leads to the synthesis of dipeptide species and their chemisorption (Takahagi et al, 2019). Other researchers have focused on the thermolysis and polymerization reactions of hydrogen cyanide under simple hydrothermal conditions (Das et al, 2019;Villafañe-Barajas et al, 2020a, 2020b and showed the formation of several organic compounds, suggesting that this kind of reactions could occur in the vicinity of hydrothermal vents. Moreover, other studies suggest that ferrocyanide solutions are stables at lower p CO 2 , temperature <25°C and higher pH (6.9-9.3); for example, in environments saturated in carbonate or bicarbonate brines (Toner and Catling, 2019).…”