scholarly journals The Roles of Thiyl Radicals in the Radiolysis of a Mixed Aqueous Solution of Cysteine and Formate— Hydrogen Abstraction from Formate and the Formation of Carbon Dioxide

1971 ◽  
Vol 44 (8) ◽  
pp. 2257-2258 ◽  
Author(s):  
Makio Morita ◽  
Katsuro Sasai ◽  
Makoto Tajima ◽  
Masao Fujimaki
Keyword(s):  
Carbon Dioxide ◽  
Aqueous Solution ◽  
Hydrogen Abstraction ◽  
Thiyl Radicals ◽  
Mixed Aqueous Solution

Atom Condensed Fukui Function for Condensed Phases and Biological Systems and Its Application to Enzymatic Fixation of Carbon Dioxide

2019 ◽  
Author(s):  
Javier Oller ◽  
David A. Sáez ◽  
Esteban Vöhringer-Martinez
Keyword(s):  
Carbon Dioxide ◽  
Aqueous Solution ◽  
Molecular System ◽  
Chemical Reactivity ◽  
Nucleophilic Attack ◽  
Stable Conformation ◽  
Fukui Functions ◽  
Reactivity Descriptors ◽  
Dynamics Simulations ◽  
Fixation Of Carbon Dioxide

<div><div><div><p>Local reactivity descriptors such as atom condensed Fukui functions are promising computational tools to study chemical reactivity at specific sites within a molecule. Their applications have been mainly focused on isolated molecules in their most stable conformation without considering the effects of the surroundings. Here, we propose to combine QM/MM Born-Oppenheimer molecular dynamics simulations to obtain the microstates (configurations) of a molecular system using different representations of the molecular environment and calculate Boltzmann weighted atom condensed local reac- tivity descriptors based on conceptual DFT. Our approach takes the conformational fluctuations of the molecular system and the polarization of its electron density by the environment into account allowing us to analyze the effect of changes in the molecular environment on reactivity. In this contribution, we apply the method mentioned above to the catalytic fixation of carbon dioxide by crotonyl-CoA carboxylase/reductase and study if the enzyme alters the reactivity of its substrate compared to an aqueous solution. Our main result is that the protein en- vironment activates the substrate by the elimination of solute-solvent hydrogen bonds from aqueous solution in the two elementary steps of the reaction mechanism: the nucleophilic attack of a hydride anion from NADPH on the α, β unsaturated thioester and the electrophilic attack of carbon dioxide on the formed enolate species.</p></div></div></div>

Photooxidation at Platinum Colloidal TiO2 Aqueous-Solution Interfaces. I. Ethylenediaminetetraacetic Acid and Related-Compounds

1986 ◽  
Vol 39 (5) ◽  
pp. 757 ◽  
Author(s):  
DN Furlong ◽  
D Wells ◽  
WHF Sasse
Keyword(s):  
Carbon Dioxide ◽  
Aqueous Solution ◽  
Ethylenediaminetetraacetic Acid ◽  
Oxidation Potential ◽  
Illumination Time ◽  
Carbonium Ions ◽  
Production Of Hydrogen ◽  
Glycine Derivatives ◽  
Lactic Acids ◽  
Exhaustive Oxidation

The photooxidation of ethylenediaminetetraacetic acid ( edta ) and related glycine derivatives, at Pt/TiO2/aqueous solution interfaces, has been monitored via the production of hydrogen and carbon dioxide. Yields are consistent with the exhaustive oxidation of methoxycarbonyl groups and the rate varied with the number and distribution of such groups. A photooxidation pathway is proposed which involves the oxidation of intermediate carbonium ions. Plausible molecular intermediates, such as formic acid and formaldehyde in the case of edta , have been shown in separate experiments to be photooxidized according to the proposed pathway. The maximum rate of oxidation for each donor depends on its oxidation potential and its tendency to adsorb on TiO2 surfaces. Desorption due to pH increase, as well as consumption of the donor, causes the rate to decline rapidly with illumination time. Acetic and malonic acids gave some hydrogen but underwent mainly (> c. 80%) photo-Kolbe decarboxylation to yield carbon dioxide and methane. By contrast the oxidation of oxomalonic, pyruvic and lactic acids proceeded mainly via a H2 producing pathway similar to that established for edta. The oxidation of pyruvic and lactic acids ceased at a yield of one mole of CO2 per mole of acid.

scholarly journals Thermo-Responsive Behavior of Mixed Aqueous Solution of Hydrophilic Polymer with Pendant Phosphorylcholine Group and Poly(Acrylic Acid)

Polymers ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 148
Author(s):  
Hirokazu Fukumoto ◽  
Kazuhiko Ishihara ◽  
Shin-Ichi Yusa
Keyword(s):  
Aqueous Solution ◽  
Acrylic Acid ◽  
Solution Temperature ◽  
Interpolymer Complex ◽  
Mixed Aqueous Solution ◽  
Upper Critical Solution Temperature ◽  
Acidic Conditions ◽  
Decreasing Ph ◽  
Increasing Temperature ◽  
Poly Acrylic Acid

A mixed aqueous solution of hydrophilic poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) and poly(acrylic acid) (PAAc) becomes cloudy under acidic conditions at room temperature. The pendant carboxylic acid groups in PAAc form hydrogen bonds with the ester and phosphate groups in PMPC. While the polymers aggregate under acidic conditions, neither one associate under basic conditions because of the deprotonation of the pendant carboxy groups in PAAc. We observed that the interpolymer complex formed from PMPC, and PAAc was dissociated in aqueous solutions with increasing temperature, which is an upper critical solution temperature behavior. With increasing temperature, the molecular motion increased to dissociate the interpolymer complex. The phase transition temperature increased with increasing polymer and salt concentrations, and with decreasing pH.

Chemical Absorption of Carbon Dioxide into Aqueous Solution of Potassium Threonate

2010 ◽  
Vol 45 (4) ◽  
pp. 497-507 ◽  
Author(s):  
Kyu-Suk Hwang ◽  
Dae-Won Park ◽  
Kwang-Joong Oh ◽  
Seong-Soo Kim ◽  
Sang-Wook Park
Keyword(s):  
Carbon Dioxide ◽  
Aqueous Solution ◽  
Chemical Absorption

scholarly journals Preparation of highly stable polypyrrole dispersions in the mixed aqueous solution of sodium dodecyl sulfate and polyvinyl pyrrolidone

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Xing Shuangxi ◽  
Zhao Guoku
Keyword(s):  
Aqueous Solution ◽  
Sodium Dodecyl Sulfate ◽  
Sodium Dodecyl ◽  
Polyvinyl Pyrrolidone ◽  
Component Solution ◽  
Mixed Aqueous Solution ◽  
Polymeric Stabilizer ◽  
Structure Morphology ◽  
Dodecyl Sulfate ◽  
Proper Mass

AbstractPolypyrrole (PPy) dispersions with high stability were prepared in the mixed aqueous solution comprising an anionic surfactant (sodium dodecyl sulfate, SDS) and a polymeric stabilizer (polyvinyl pyrrolidone, PVP). By choosing proper mass ratios of the surfactant to the monomer, stable dispersions could be obtained owing to the interaction between the two components. The structure, morphology, stability, particle size, polydispersity index and conductivity of the samples obtained from different conditions were investigated. The PPy dispersions prepared from mixed aqueous solutions were much more stable than those from single component solution.

Kinetics of One-Electron Oxidation of Thiols and Hydrogen Abstraction by Thiyl Radicals from .alpha.-Amino C-H Bonds

1994 ◽  
Vol 116 (26) ◽  
pp. 12010-12015 ◽  
Author(s):  
Rong Zhao ◽  
Johan Lind ◽  
Gabor Merenyi ◽  
Trygve E. Eriksen
Keyword(s):  
Hydrogen Abstraction ◽  
Thiyl Radicals ◽  
Kinetics Of
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