Stopped-flow Spectrophotometric Study on the Reaction between Carbon Dioxide and [Co(NH3)4(H2O)2]3+ Ion in Aqueous Solution

2007 ◽  
Vol 633 (9) ◽  
pp. 1493-1499 ◽  
Author(s):  
Dagmara Jacewicz ◽  
Agnieszka Chylewska ◽  
Aleksandra Da;akbrowska ◽  
Lech Chmurzyński
Keyword(s):  
Carbon Dioxide ◽  
Aqueous Solution ◽  
Spectrophotometric Study ◽  
Stopped Flow

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.

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

N-ACYL SUBSTITUTED PHENYLHYDROXYLAMINES: THE EFFECT OF RADICAL CHANGE ON ANALYTICAL BEHAVIOR

1957 ◽  
Vol 35 (12) ◽  
pp. 1454-1460 ◽  
Author(s):  
C. A. Armour ◽  
D. E. Ryan
Keyword(s):  
Aqueous Solution ◽  
Stability Constant ◽  
Radical Change ◽  
Spectrophotometric Study ◽  
Iron Complex ◽  
Membered Ring ◽  
Analytical Reagents ◽  
Colorimetric Reagent ◽  
Analytical Behavior

The synthesis of a number of N-acyl substituted phenylhydroxylamines is outlined and the effect of the change in the nature of the acyl group on their usefulness as analytical reagents is described. Stability constant measurements in alcohol show an increase in stability with an increase in basicity of reagent regardless of the nature of the attached group; their ability to precipitate complexes from aqueous solution, however, is markedly dependent on the nature of the attached radical. A spectrophotometric study shows the existence of both a 1:1 and a 1:3 iron complex. A more sensitive colorimetric reagent results with an unsaturated five-membered ring as the attached grouping.

The mechanism of the oxidation of thiocyanate ion by peroxomonosulphate in aqueous solution. II. Kinetics of the reaction

1966 ◽  
Vol 19 (8) ◽  
pp. 1365 ◽  
Author(s):  
RH Smith ◽  
IR Wilson
Keyword(s):  
Aqueous Solution ◽  
Initial Rate ◽  
Stopped Flow ◽  
Thiocyanate Ion ◽  
First Order ◽  
Conductance Method ◽  
Rate Of Reaction ◽  
Kinetics Of

Initial rates of reaction for the above oxidation have been measured by a stopped-flow conductance method. Between pH 2 and 3.6, the initial rate of reaction, R, is given by the expression R{[HSO5-]+[SCN-]} = {kb+kc[H+]}[HSO5-]0[SCN-]20+ka[H+]-1[HSO5]20[SCN-]0 As pH increases, there is a transition to a pH-independent rate, first order in each thiocyanate and peroxomonosulphate concentrations.

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