Theoretical Investigation of Competing Mechanisms in the Thermal Unimolecular Decomposition of Acetic Acid and the Hydration Reaction of Ketene

1995 ◽  
Vol 117 (18) ◽  
pp. 5114-5119 ◽  
Author(s):  
Xiaofeng Duan ◽  
Michael Page
Keyword(s):  
Acetic Acid ◽  
Theoretical Investigation ◽  
Hydration Reaction ◽  
Unimolecular Decomposition

Theoretical Investigation of Mechanisms for the Gas-Phase Unimolecular Decomposition of DMMP

2009 ◽  
Vol 113 (49) ◽  
pp. 13762-13771 ◽  
Author(s):  
Li Yang ◽  
Robert M. Shroll ◽  
Jiaxu Zhang ◽  
U. Lourderaj ◽  
William L. Hase
Keyword(s):  
Gas Phase ◽  
Theoretical Investigation ◽  
Unimolecular Decomposition

THE CHROMIC ACID OXIDATION OF ARYL TRIFLUOROMETHYL ALCOHOLS: ISOTOPE AND SUBSTITUENT EFFECTS

1964 ◽  
Vol 42 (2) ◽  
pp. 439-446 ◽  
Author(s):  
Ross Stewart ◽  
Donald G. Lee
Keyword(s):  
Acetic Acid ◽  
Acid Solution ◽  
Chromic Acid ◽  
Isotope Effects ◽  
Acetic Acid Solution ◽  
Substituent Effects ◽  
Acid Oxidation ◽  
Unimolecular Decomposition ◽  
Chromic Acid Oxidation ◽  
Deuterium Isotope Effects

The mechanism of the chromic acid oxidation of eight aryltrmuoromethylcarbinols has been studied in acetic acid solution. Electron-donating substituents accelerate the reaction and a good correlation of rate with σ+ values has been found. The rho value is −1.01. Deuterium isotope effects for the oxidation of five of these compounds have been determined and the magnitude of the isotope effect has been found to correlate inversely with the ease of oxidation of the alcohol.The results are interpreted in terms of a unimolecular decomposition of the chromate ester of the alcohol.

Hydration of the carbonyl group — Acetic acid catalysis in the co-operative mechanism

2005 ◽  
Vol 83 (6-7) ◽  
pp. 769-785 ◽  
Author(s):  
Yih-Huang Hsieh ◽  
Noham Weinberg ◽  
Kiyull Yang ◽  
Chan-Kyung Kim ◽  
Zheng Shi ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Carbonyl Group ◽  
Isotope Shift ◽  
Acid Catalysis ◽  
Water Molecules ◽  
Hydration Reaction ◽  
Water Solvent ◽  
General Acid ◽  
O Isotope ◽  
Acid Catalyzed

In a co-operative reaction, solvent molecules, specifically water molecules, participate actively in the mechanism to circumvent the formation of charged intermediates. This paper extends our earlier theoretical treatment of the neutral co-operative hydration of acetone to include general acid catalysis by acetic acid. As before, the predominant neutral channel employs three catalytic water molecules. The principal acetic acid catalyzed channels employ one catalytic water molecule and, in approximately equal proportions, one or both oxygens of the carboxyl group. The theoretical rate constant for general acid catalysis is calculated to be 0.49 M–1 s–1 at 298 K. This compares to an estimated experimental value of 0.30 M–1 s–1 for acetic acid catalyzed hydration of acetone at 298 K in water solvent, determined by using the 18O-isotope shift in the 13C NMR spectrum of 2-13C-labelled acetone as a kinetic probe. It is concluded that the notion of co-operativity can be extended to include general acid catalysis of the hydration of a carbonyl group in water solvent. This creates an obvious problem for the generally accepted view that multistep ionic mechanisms are operative in the low dielectric media that exist at the active sites of hydrolytic enzymes. The relevance of this finding to the mechanisms of action of β-lactam antibiotics has been noted.Key words: hydration, reaction mechanism, co-operativity, general acid catalysis, ab initio, SCRF, 18O-isotope shift.

A Theoretical Investigation of 1-Butanol Unimolecular Decomposition

2015 ◽  
pp. 384-393 ◽  
Author(s):  
Leonardo Pacifici ◽  
Noelia Faginas-Lago ◽  
Andrea Lombardi ◽  
Nadia Balucani ◽  
Domenico Stranges ◽  
...  
Keyword(s):  
Theoretical Investigation ◽  
Unimolecular Decomposition
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