Compounds of chromium(VI): The pyridine – chromic anhydride complex, benzimidazolinium dichromate, and three 2-alkyl-1H-benzimida -zolinium dichromates

2003 ◽  
Vol 81 (6) ◽  
pp. 612-619 ◽  
Author(s):  
T Stanley Cameron ◽  
Jason AC Clyburne ◽  
Pramod K Dubey ◽  
J Stuart Grossert ◽  
K Ramaiah ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Acetic Acid ◽  
Chromium Trioxide ◽  
Aqueous Acetic Acid ◽  
Secondary Alcohols ◽  
Chromic Anhydride ◽  
Acid Base ◽  
Chromium Vi ◽  
Oxidation Of Alcohols ◽  
Dichromate Anions

Pyridine, when allowed to react with chromic anhydride under strictly anhydrous conditions, gives the known, very air-sensitive, crystalline 2:1 Lewis acid–base complex 1. The crystal structure has now been successfully determined. When benzimidazole and three 2-alkyl-1H-benzimidazoles were treated with chromium trioxide in aqueous acetic acid, crystalline dichromate salts (2–5) were readily formed. These salts consist of dichromate anions linked to the cations by hydrogen bonds of the type N—H···O. The chromium atoms have distorted tetrahedral environments, with the Cr—O distances being typical for dichromate anions. In the cases of the 2-methyl and 2-ethyl salts, the anions are disordered about a centre of inversion. The hydrogen bonding arrangements are discussed and the structures are compared with other oxygenated chromium(VI) species. The dichromate salts are useful selective oxidants for a range of primary and secondary alcohols; examples of these reactions are reported.Key words: chromium(VI), pyridine – chromium trioxide complex, benzimidazolinium dichromate salts, controlled oxidation of alcohols.

scholarly journals Kinetic Evidence of a Common Mechanism in the Oxidation by Chromium(vi) Complexes: Oxidation of Benzyl Alcohol

2000 ◽  
Vol 2000 (3) ◽  
pp. 114-115 ◽  
Author(s):  
Chockalingam Karunakaran ◽  
Sadasivam Suresh
Keyword(s):  
Acetic Acid ◽  
Benzyl Alcohol ◽  
Perchloric Acid ◽  
Mineral Acid ◽  
Common Mechanism ◽  
Aqueous Acetic Acid ◽  
First Order ◽  
Chromium Vi ◽  
Oxidation Of Benzyl Alcohol

The oxidation of benzyl alcohol by dichromate and seven chromium(VI) complexes in aqueous acetic acid in the presence of perchloric acid is first order each in the oxidants, the alcohol and the mineral acid. The oxidation conforms to the isokinetic and Exner relationships and follows a common mechanism.

Kinetics of the chromic acid oxidation of alcohols in aqueous acetone solutions

1968 ◽  
Vol 46 (3) ◽  
pp. 441-449 ◽  
Author(s):  
Donald G. Lee ◽  
William L. Downey ◽  
R. Michael Maass
Keyword(s):  
Acetic Acid ◽  
Chromic Acid ◽  
Aqueous Acetone ◽  
Acid Oxidation ◽  
Aqueous Acetic Acid ◽  
Acid Solutions ◽  
Deuterium Isotope Effect ◽  
Chromic Acid Oxidation ◽  
Oxidation Of Alcohols ◽  
Kinetics Of

The rate law for oxidation of 2-propanol by chromic acid in aqueous acetone solutions has been found to be V = k3 [Cr(VI)| [2-propanol]ho, with the magnitude of k3 being over 700 times as great in 93.3% acetone as it is in water. In other respects (primary deuterium isotope effect, Hammett "rho" value, and salt effects) the general features of the reaction strongly resemble those observed in aqueous acetic acid solutions.

Oxidation of l-rhamnose and d-mannose by chromium(VI) in aqueous acetic acid

Polyhedron ◽  
1996 ◽  
Vol 15 (9) ◽  
pp. 1517-1523 ◽  
Author(s):  
M. Rizzotto ◽  
M.I. Frascaroli ◽  
S. Signorella ◽  
L.F. Sala
Keyword(s):  
Acetic Acid ◽  
Aqueous Acetic Acid ◽  
Chromium Vi

Equilibria in acetic acid: ionic association constant of oxonium perchlorate, acid-base equilibrium constant of oxonium acetate, and autoprotolysisconstant of acetic acid at 105.7°

1965 ◽  
Vol 18 (3) ◽  
pp. 321 ◽  
Author(s):  
RJL Martin
Keyword(s):  
Dielectric Constant ◽  
Acetic Acid ◽  
Equilibrium Constant ◽  
Association Constant ◽  
Ionic Association ◽  
Aqueous Acetic Acid ◽  
Equivalent Conductivity ◽  
Acid Base ◽  
Base Equilibrium ◽  
Acid Base Equilibrium

In aqueous acetic acid, 0.114-0.152M H2O, at 105.7�, oxonium perchlorate has limiting equivalent conductivity Λ0 90.7, ionic association constant KA = [H3O+ClO4-]/[H3O+][ClO4]f2 = 0.0310 x 106 and centre-to-centre distance between the ions (� = 4.84 Ǻ. The acid-base equilibrium constant for oxonium acetate KB = [ΣH3O+ OAc-]/[H2O] increases with the dielectric constant so that -log KB = 1.532+29.44/D. The autoprotolysis of acetic acid also increases with the dielectric constant.

Identification of valence electronic states of aqueous acetic acid in acid–base equilibrium using site-selective X-ray emission spectroscopy

2009 ◽  
Vol 11 (39) ◽  
pp. 8676 ◽  
Author(s):  
Yuka Horikawa ◽  
Takashi Tokushima ◽  
Yoshihisa Harada ◽  
Osamu Takahashi ◽  
Ashish Chainani ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Emission Spectroscopy ◽  
Electronic States ◽  
Aqueous Acetic Acid ◽  
Acid Base ◽  
X Ray ◽  
Base Equilibrium ◽  
Acid Base Equilibrium ◽  
Site Selective

Acid hydrolysis of acetamide in aqueous acetic acid

1965 ◽  
Vol 18 (6) ◽  
pp. 807 ◽  
Author(s):  
RJL Martin
Keyword(s):  
Acetic Acid ◽  
Reaction Rate ◽  
Ion Pairs ◽  
Bimolecular Reaction ◽  
Aqueous Acetic Acid ◽  
Acid Base ◽  
Wide Range ◽  
Triple Ions ◽  
Association Equilibria ◽  
Hydrolysis Of

The hydrolysis of acetamide in acetic acid has been studied over a wide range of reactant and salt concentrations. The various acid-base and ionic association equilibria must be considered in the interpretation of the data. It is shown that the mechanism is a bimolecular reaction between water and the acetamidium ion and that the acetamidium ion pairs and triple ions have no reactivity. Polar substances such as water and acetamide, apart from undergoing reaction, also increase the reaction rate by favouring the dissociation of the ion pairs. Salts exhibit strong ionic strength and ion-pair effects.

Novel Compound from Flowers of Moringa oleifera Active Against Multi- Drug Resistant Gram-negative Bacilli

2020 ◽  
Vol 20 (1) ◽  
pp. 69-75
Author(s):  
Santi M. Mandal ◽  
Subhanil Chakraborty ◽  
Santanu Sahoo ◽  
Smritikona Pyne ◽  
Samaresh Ghosh ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Moringa Oleifera ◽  
Aqueous Acetic Acid ◽  
Phytochemical Analysis ◽  
Hydroxyl Groups ◽  
Drug Resistant ◽  
Gram Negative ◽  
Isolated Compound ◽  
Conventional Antibiotics

Background: The need for suitable antibacterial agents effective against Multi-drug resistant Gram-negative bacteria is acknowledged globally. The present study was designed to evaluate the possible antibacterial potential of an extracted compound from edible flowers of Moringa oleifera. Methods: Five different solvents were used for preparing dried flower extracts. The most effective extract was subjected to fractionation and further isolation of the active compound with the highest antibacterial effect was obtained using TLC, Column Chromatography and reverse phase- HPLC. Approaches were made for characterization of the isolated compound using FTIR, NMR and Mass spectrometry. Antibacterial activity was evaluated according to the CLSI guidelines. Results: One fraction of aqueous acetic acid extract of M. oleifera flower was found highly effective and more potent than conventional antibiotics of different classes against Multi-drug resistant Gram-negative bacilli (MDR-GNB) when compared. The phytochemical analysis of the isolated compound revealed the presence of hydrogen-bonded amine and hydroxyl groups attributable to unsaturated amides. Conclusion: The present study provided data indicating a potential for use of the flowers extract of M. oleifera in the fight against infections caused by lethal MDR-GNB. Recommendations: Aqueous acetic acid flower extract of M. oleifera is effective, in-vitro, against Gram-negative bacilli. This finding may open a scope in pharmaceutics for the development of new classes of antibiotics.

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