Nonconventional versus conventional application of pseudo‐first‐order kinetics to fundamental organic reactions

Abstract

Three new analysis procedures for pseudo-first-order kinetics are introduced and applied to eight different fundamental organic reactions. The reactions belong to the following classes: nitroalkane proton transfer, formal hydride ion transfers from NADH model compounds, and S N 2 reactions of alkyl halides with ionic and neutral nucleophiles. The three methods consist of (1) half-life dependence of k app , (2) sequential linear pseudo-first-order correlation, and (3) revised instantaneous rate constant analysis. Each of the three procedures is capable of distinguishing between one-and multistep mechanisms, and the combination of the three procedures provides a powerful strategy for differentiating between the two mechanistic possibilities. The data from the eight reactions chosen as examples clearly show how the procedures work in practice.

Equivalency of Kinetic Schemes: Causes and an Analysis of Some Model Fitting Algorithms

“…The first, classical approach is individual evaluation of the kinetic curves. Based on this approach, an algorithm has been proposed to determine whether the reaction mechanism is complicated or not. The correct model should not contradict the shape of kinetic curves, the k obs – C X dependence, the stoichiometry of the reaction, or the determined number of reaction components .…”

Oxygen-Initiated Chain Mechanism for Hydride Transfer Between NADH and NAD+ Models. Reaction of 1-Benzyl-3-Cyanoquinolinium Ion with N-Methyl-9,10-Dihydroacridine in Acetonitrile

“…Under these conditions, we found that, at reaction temperatures below 308 K, we could not observe any deviations from simple first-order kinetics. Since that time our non-steady-state kinetic methods have continually developed and been improved significantly. − Due to the negative critique of our mechanism and the incomplete nature of our experimental study, the data that this paper is based on were obtained using our most recently developed kinetic techniques. − …”

“…Instantaneous rate constant (IRC) analysis , of the reactions between MAH/MAH- d 2 and BQCN + in AN is illustrated by the plots in Figure . An important feature of the plots in Figure is that the experimental data for these figures was the increase in absorbance at 440 nm.…”