Adsorption of HCN onto sodium montmorillonite dependent on the pH as a component to chemical evolution

2014 ◽  
Vol 13 (4) ◽  
pp. 310-318 ◽  
Author(s):  
M. Colin-Garcia ◽  
A. Heredia ◽  
A. Negron-Mendoza ◽  
F. Ortega ◽  
T. Pi ◽  
...  
Keyword(s):  
Chemical Evolution ◽  
Molecular Model ◽  
Three Dimensional ◽  
Channel Structure ◽  
Mineral Surfaces ◽  
Sodium Montmorillonite ◽  
Complex Molecules ◽  
Prebiotic Chemical ◽  
Physical And Chemical

AbstractThe aim of this work is to study the behaviour of hydrogen cyanide (HCN) adsorbed onto mineral surfaces (sodium montmorillonite, a clay mineral) in different pH environments as a possible prebiotic process for complexation of organics. Our experimental results show that specific sites on the surface of the clay increased the concentration of HCN molecules dependent on the pH values. Moreover, this adsorption can occur through physical and chemical interactions enhanced by the channel structure of the sodium montmorillonite. The three-dimensional channelling structure of the clay accumulates the organics, hindering the releasing (desorption) of the organic molecules. A molecular model developed here also confirms the role of the pH as a regulating factor in the adsorption of HCN onto the inorganic surfaces and the possibility for further reactions forming more complex molecules, as an abiotic mechanism important in prebiotic chemical evolution processes.

scholarly journals Role of Mineral Surfaces in Prebiotic Chemical Evolution. In Silico Quantum Mechanical Studies

Life ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 10 ◽  
Author(s):  
Albert Rimola ◽  
Mariona Sodupe ◽  
Piero Ugliengo
Keyword(s):  
Chemical Evolution ◽  
In Silico ◽  
Density Functional ◽  
Quantum Mechanical ◽  
Mineral Surfaces ◽  
Chemical Complexity ◽  
Organic Mineral ◽  
Mechanical Methods ◽  
Prebiotic Chemical

There is a consensus that the interaction of organic molecules with the surfaces of naturally-occurring minerals might have played a crucial role in chemical evolution and complexification in a prebiotic era. The hurdle of an overly diluted primordial soup occurring in the free ocean may have been overcome by the adsorption and concentration of relevant molecules on the surface of abundant minerals at the sea shore. Specific organic–mineral interactions could, at the same time, organize adsorbed molecules in well-defined orientations and activate them toward chemical reactions, bringing to an increase in chemical complexity. As experimental approaches cannot easily provide details at atomic resolution, the role of in silico computer simulations may fill that gap by providing structures and reactive energy profiles at the organic–mineral interface regions. Accordingly, numerous computational studies devoted to prebiotic chemical evolution induced by organic–mineral interactions have been proposed. The present article aims at reviewing recent in silico works, mainly focusing on prebiotic processes occurring on the mineral surfaces of clays, iron sulfides, titanium dioxide, and silica and silicates simulated through quantum mechanical methods based on the density functional theory (DFT). The DFT is the most accurate way in which chemists may address the behavior of the molecular world through large models mimicking chemical complexity. A perspective on possible future scenarios of research using in silico techniques is finally proposed.

Histidine Self-assembly and Stability on Mineral Surfaces as a Model of Prebiotic Chemical Evolution: An Experimental and Computational Approach

2021 ◽  
Author(s):  
D. Madrigal-Trejo ◽  
P.S. Villanueva-Barragán ◽  
R. Zamudio-Ramírez ◽  
K. E. Cervantes-de la Cruz ◽  
I. Mejía-Luna ◽  
...  
Keyword(s):  
Chemical Evolution ◽  
Self Assembly ◽  
Computational Approach ◽  
Mineral Surfaces ◽  
Prebiotic Chemical

scholarly journals Investigation of the Physical and Chemical Characteristics of the Zeolites of the Kholinsky Deposit

2021 ◽  
Vol 10 (4) ◽  
pp. 65-71
Author(s):  
A. V. Bondarev ◽  
E. T. Zhilyakova ◽  
N. B. Demina ◽  
K. K. Razmakhnin
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Raw Materials ◽  
Molecular Model ◽  
Three Dimensional ◽  
Chemical Characteristics ◽  
Structural Level ◽  
Mineral Raw Materials ◽  
Physical And Chemical ◽  
Sorption Characteristics

Introduction. The mineral resource base of Russia has effective sorption substances that meet pharmaceutical requirements. Promising mineral raw materials are Zeolites, which combine the properties of an adsorbent and a "molecular sieve" due to the porous structure. In addition to the enterosorption direction, natural Zeolites are a source of macro-and microelements, which determines their use as biologically active food additives.Aim. Study of the physical and chemical characteristics of the Zeolites of the Kholinsky deposit.Materials and methods. The zeolite mineral raw materials of the Kholinsky deposit were used as objects of research. Optical microscopy was performed using a Leica DM direct microscope (Microsystems, Germany). Energy dispersion analysis was performed using an electron scanning microscope JSM-5300 (Jeol Ltd, Japan). The sorption characteristics were studied using the ASAP 2400 device (Micromeritics, USA) according to the method. The construction of a virtual three-dimensional molecular model of the Zeolite was carried out using the program Java Applet Jmol.Results and discussion. The physicochemical properties of Zeolites are investigated. It is established that morphologically the particles of the zeolite phase have a size of 5-30 microns, they are evenly distributed over the entire area of the site and represent the first structural level. Particles of the zeolite phase with a size of 5-6 microns form the second structural level due to Clinoptilolite crystals, microcracks and microgeodes. Based on the energy-dispersion spectral analysis, an increased content of the elements K, Na was revealed, which indicates the alkaline composition of the cation exchange complex. The studied Zeolite samples have micropores (volume 0.0031 cm3/g), mesopores (volume 0.0675 cm3/g), and a specific surface area of 29.1840 m2/g. A virtual three-dimensional molecular model of the Zeolite of the Kholinsky deposit has been developed. According to the molecular model, the sorption characteristics of the Kholinsky deposit Zeolite were: specific surface area - 1096.31 m2/g (1916.34 m2/cm3), the average diameter of the spherical molecule for adsorption in the pores is 5.97 A.Conclusion. The analysis of the sorption characteristics of the Zeolite revealed the following features: the pores occupy half the volume of the entire Zeolite, which are available for the sorption of water and low-molecular substances. Each pore in three mutually perpendicular directions communicates with the neighboring ones through "windows". A system of intracrystalline pores and cavities is formed, in which the occlusion and adsorption of molecules of the appropriate size easily occurs.

Sequence Analysis and Functional Interpretation of α-Amylase Receptor from Anopheles albimanus Using a Molecular Model

2013 ◽  
Vol 798-799 ◽  
pp. 1095-1098
Author(s):  
Shi Ping Shan ◽  
Dong Xia Du ◽  
De Yuan Zhang ◽  
Zhao Hui Guo
Keyword(s):  
Brush Border Membrane ◽  
Molecular Model ◽  
Membrane Vesicle ◽  
Three Dimensional ◽  
Binding Pocket ◽  
Dimensional Structure ◽  
Substrate Binding Pocket ◽  
Functional Interpretation ◽  
Three Dimensional Structure

Activated toxins interact with α-amylase receptor on the brush border membrane vesicle (BBMV) of the midgut epithelium, which activates intracellular oncotic pathways and leads to cell death. In order to decipher the mechanism of process how toxins interact with their receptors, it is essential to investigate their three-dimensional structure. The three-dimensional structure of α-amylase was constructed by homology modeling, based on crystal structure ofBacillus cereusoligo-1,6-glucosidase and the model was further evaluated using PROSA energy and ERRAT. The substrate binding pocket responsible for the interactions with toxins was predicted and analyzed, and the important role of binding of toxin to binding pocket on α-amylase was discussed in the aspect of Cry4Ba and Cry11Aa toxicity.

scholarly journals The role of convection in AGB modeling

2006 ◽  
Vol 2 (S239) ◽  
pp. 258-265
Author(s):  
Paolo Ventura
Keyword(s):  
Mass Loss ◽  
Chemical Evolution ◽  
Cross Sections ◽  
Stellar Evolution ◽  
Asymptotic Giant Branch ◽  
Intermediate Mass ◽  
Convective Envelope ◽  
Evolutionary Phase ◽  
Physical And Chemical

AbstractThe modeling of the Asymptotic Giant Branch phase is made highly uncertain by some still unsolved issues related to the input macro-physics used to calculate the stellar evolution, namely mass loss, nuclear cross sections, overshooting and convective modeling. We show that in the massive intermediate mass models, which achieve at the bottom of their convective envelope temperatures sufficiently high to favour an advanced nucleosynthesis, the treatment of convection plays a major role in determining the physical and chemical evolution of the stellar models during this evolutionary phase.

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

2020 ◽  
Vol 19 (5) ◽  
pp. 369-378 ◽  
Author(s):  
Saúl A. Villafañe-Barajas ◽  
María Colín-García ◽  
Alicia Negrón-Mendoza ◽  
Marta Ruiz-Bermejo
Keyword(s):  
Chemical Evolution ◽  
Hydrogen Cyanide ◽  
Organic Molecules ◽  
Chemical Species ◽  
Hydrothermal Systems ◽  
Raw Material ◽  
Complex Molecules ◽  
Prebiotic Molecules ◽  
The Stability

AbstractHydrogen 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.

Stability of α-ketoglutaric acid simulating an impact-generated hydrothermal system: implications for prebiotic chemistry studies

2020 ◽  
Vol 19 (3) ◽  
pp. 253-259
Author(s):  
L. Ramírez-Vázquez ◽  
A. Negrón-Mendoza
Keyword(s):  
Chemical Reactions ◽  
Chemical Evolution ◽  
Hydrothermal System ◽  
Krebs Cycle ◽  
Physicochemical Process ◽  
Energy Sources ◽  
Mineral Surfaces ◽  
The Past ◽  
The Stability

AbstractLife originated on Earth possibly as a physicochemical process; thus, geological environments and their hypothetical characteristics on early Earth are essential for chemical evolution studies. Also, it is necessary to consider the energy sources that were available in the past and the components that could have contributed to promote chemical reactions. It has been proposed that the components could have been mineral surfaces. The aim of this work is to determine the possible role of mineral surfaces on chemical evolution, and to study of the stability of relevant molecules for metabolism, such as α-ketoglutaric acid (α-keto acid, Krebs cycle participant), using ionizing radiation and thermal energy as energy sources and mineral surfaces to promote chemical reactions. Preliminary results show α-ketoglutaric acid can be relatively stable at the simulated conditions of an impact-generated hydrothermal system; thus, those systems might have been plausible environments for chemical evolution on Earth.

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

Life ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 661
Author(s):  
Saúl A. Villafañe-Barajas ◽  
Marta Ruiz-Bermejo ◽  
Pedro Rayo-Pizarroso ◽  
Santos Gálvez-Martínez ◽  
Eva Mateo-Martí ◽  
...  
Keyword(s):  
Chemical Evolution ◽  
Hydrogen Cyanide ◽  
Organic Molecule ◽  
Organic Molecules ◽  
Analytical Techniques ◽  
Mineral Surfaces ◽  
Mineral Surface ◽  
Molecular Complexity ◽  
Molecule Production

Hydrogen cyanide, HCN, is considered a fundamental molecule in chemical evolution. The named HCN polymers have been suggested as precursors of important bioorganics. Some novel researches have focused on the role of mineral surfaces in the hydrolysis and/or polymerization of cyanide species, but until now, their role has been unclear. Understanding the role of minerals in chemical evolution processes is crucial because minerals undoubtedly interacted with the organic molecules formed on the early Earth by different process. Therefore, we simulated the probable interactions between HCN and a serpentinite-hosted alkaline hydrothermal system. We studied the effect of serpentinite during the thermolysis of HCN at basic conditions (i.e., HCN 0.15 M, 50 h, 100 °C, pH > 10). The HCN-derived thermal polymer and supernatant formed after treatment were analyzed by several complementary analytical techniques. The results obtained suggest that: I) the mineral surfaces can act as mediators in the mechanisms of organic molecule production such as the polymerization of HCN; II) the thermal and physicochemical properties of the HCN polymer produced are affected by the presence of the mineral surface; and III) serpentinite seems to inhibit the formation of bioorganic molecules compared with the control (without mineral).

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