Kinetics and mechanism of benzoylformate decarboxylase using carbon-13 and solvent deuterium isotope effects on benzoylformate and benzoylformate analogs

Biochemistry ◽  
1988 ◽  
Vol 27 (6) ◽  
pp. 2197-2205 ◽  
Author(s):  
Paul M. Weiss ◽  
George A. Garcia ◽  
George L. Kenyon ◽  
W. W. Cleland ◽  
Paul F. Cook
Keyword(s):  
Isotope Effects ◽  
Kinetics And Mechanism ◽  
Benzoylformate Decarboxylase ◽  
Deuterium Isotope Effects

Kinetics and mechanism of the oxidation of alcohols by tetrapropylammonium perruthenate

2005 ◽  
Vol 83 (9) ◽  
pp. 1212-1221 ◽  
Author(s):  
W David Chandler ◽  
Zhao Wang ◽  
Donald G Lee
Keyword(s):  
Reaction Mechanism ◽  
Isotope Effects ◽  
Second Order ◽  
Kinetics And Mechanism ◽  
Ruthenium Dioxide ◽  
Effective Catalyst ◽  
First Order ◽  
Oxidation Of Alcohols ◽  
Autocatalytic Process ◽  
Deuterium Isotope Effects

2-Propanol is oxidized by tetrapropylammonium perruthenate (TPAP) in a reaction that is second order in TPAP and first order in 2-propanol. One of the products, believed to be ruthenium dioxide, is an effective catalyst for the reaction, making it an autocatalytic process. The rate of oxidation is relatively insensitive to the presence of substituents. Primary kinetic deuterium isotope effects are observed when either the hydroxyl or the α hydrogen is replaced by deuterium. The only product obtained from the oxidation of cyclobutanol is cyclobutanone, indicating that the reaction is a two-electron process. Tetrahydrofuran is oxidized at a rate that is several orders of magnitude slower than that observed for 2-propanol, suggesting that the reaction of TPAP with alcohols may be initiated by formation of perruthenate esters. A tentative mechanism consistent with these observations is proposed.Key words: oxidation, alcohols, tetrapropylammonium perruthenate, reaction mechanism, autocatalysis.

Mechanism of hydration and isomerisation of 4-ethylidene-2,6-di-tert-butyl-2,5-cyclohexadien-1-one. Kinetics, acid-base catalysis and solvent deuterium isotope effects

1979 ◽  
Vol 44 (1) ◽  
pp. 110-122 ◽  
Author(s):  
Jiří Velek ◽  
Bohumír Koutek ◽  
Milan Souček
Keyword(s):  
Aqueous Medium ◽  
Rate Equation ◽  
Kinetic Data ◽  
Isotope Effects ◽  
Base Catalysis ◽  
Quinone Methide ◽  
Reaction Products ◽  
Acid Base ◽  
Deuterium Isotope Effects ◽  
Hydroxybenzyl Alcohol

Competitive hydration and isomerisation of the quinone methide I at 25 °C in an aqueous medium in the region of pH 2.4-13.0 was studied spectrophotometrically. The only reaction products in the studied range of pH are 4-hydroxybenzyl alcohol (II) and 4-hydroxystyrene (III). The form of the overall rate equation corresponds to a general acid-base catalysis. The mechanism of both reactions for three markedly separated pH regions is discussed on the basis of kinetic data and solvent deuterium effect.

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