The reversible consecutive mechanism for the reaction of trinitroanisole with methoxide ion.

Although the competitive mechanism for Meisenheimer complex formation during the reaction of 2,4,6-trinitroanisole with methoxide ion in methanol is generally accepted, no kinetic evidence has been presented to rule out a reversible consecutive mechanism. Simulation of the competitive mechanism revealed that a fractional order in [MeO(-)] is predicted by the latter. Conventional pseudo-first-order analysis of the kinetics resulted in cleanly first-order in [MeO(-)], which rules out the competitive mechanism.

Hydride-exchange reactions between NADH and NAD+ model compounds under non-steady-state conditions. Apparent and real kinetic isotope effects.

The kinetics of the hydride exchange reaction between NADH model compound 10-methyl-9,10-dihydroacridine (MAH) and 1-benzyl-3-cyanoquinolinium (BQCN+) ion in acetonitrile were studied at temperatures ranging from 291 to 325 K. The extent of reaction-time profiles during the first half-lives are compared with theoretical data for the simple single-step mechanism and a 2-step mechanism involving initial donor/acceptor complex formation followed by unimolecular hydride transfer. The profiles for the reactions of MAH deviate significantly from those expected for the simple single-step mechanism with the deviation increasing with increasing temperature.

Non-steady-state kinetic study of the SN2 reaction between p-nitrophenoxide ion and methyl iodide in aprotic solvents containing water. Evidence for a 2-step mechanism.

Non-steady-state kinetic studies reveal that the SN2 reaction between p-nitrophenoxide ion and methyl iodide in acetonitrile containing water follows a 2-step mechanism involving the formation of a kinetically significant intermediate.

Resolution of the non-steady-state kinetics of the elimination of HBr from 2-(p-nitrophenyl)ethyl bromide in alcohol/alkoxide media.

Non-steady-state kinetic studies reveal that the elimination of HBr from 2-(p-nitrophenyl)ethyl bromide in alcohol/alkoxide media, the classical concerted E2 reaction, actually takes place by a two-step mechanism involving the intermediate formation of the carbanion.

Resolution of the non-steady-state kinetics of the two-step mechanism for the Diels-Alder reaction between anthracene and tetracyanoethylene in acetonitrile.

The Diels-Alder reaction between anthracene and tetracyanoethylene in acetonitrile does not reach a steady-state during the first half-life. The reaction follows the reversible consecutive second-order mechanism accompanied by the formation of a kinetically significant intermediate. The experimental observations consistent with this mechanism include extent of reaction-time profiles which deviate markedly from those expected for the irreversible second-order mechanism and initial pseudo first-order rate constants which differ significantly from those measured at longer times.