Chemical kinetics

About: Chemical kinetics is a research topic. Over the lifetime, 10614 publications have been published within this topic receiving 313446 citations. The topic is also known as: reaction kinetics.

Intramolecular long-distance electron transfer in radical anions. The effects of free energy and solvent on the reaction rates

Abstract: A homologous series of eight compounds of the general structure A-Sp-B where B is 4-biphenylyl, Sp is a rigid saturated hydrocarbon spacer, the steroidal 5..cap alpha..-androstane skeleton, and A is one of a series of 8 different molecular groups with ..pi.. electron networks was synthesized. A liquid solution of these molecules in either 2-methyltetrahydrofuran or isooctane at room temperature was subjected to a 30-ps pulse of solvated electrons. Data are presented that demonstrate in these systems the dependence of the electron transfer rates on the exothermicity of the reaction and on solvent polarity. It is also noted that the electron transfer reactions are free ion reactions.

Chemical kinetics: The study of reaction rates in solution

Abstract: Introduction to chemical kinetics simple rate equations complicated rete equations fast reactions theory of chemical kinetics phenomena for study structure-reactivity relationships medium effects appendices.

Stochastic simulation of chemical reactions with spatial resolution and single molecule detail

Abstract: Methods are presented for simulating chemical reaction networks with a spatial resolution that is accurate to nearly the size scale of individual molecules. Using an intuitive picture of chemical reaction systems, each molecule is treated as a point-like particle that diffuses freely in three-dimensional space. When a pair of reactive molecules collide, such as an enzyme and its substrate, a reaction occurs and the simulated reactants are replaced by products. Achieving accurate bimolecular reaction kinetics is surprisingly difficult, requiring a careful consideration of reaction processes that are often overlooked. This includes whether the rate of a reaction is at steady-state and the probability that multiple reaction products collide with each other to yield a back reaction. Inputs to the simulation are experimental reaction rates, diffusion coefficients and the simulation time step. From these are calculated the simulation parameters, including the 'binding radius' and the 'unbinding radius', where the former defines the separation for a molecular collision and the latter is the initial separation between a pair of reaction products. Analytic solutions are presented for some simulation parameters while others are calculated using look-up tables. Capabilities of these methods are demonstrated with simulations of a simple bimolecular reaction and the Lotka-Volterra system.

Direct Kinetic Measurements of Criegee Intermediate (CH2OO) Formed by Reaction of CH2I with O2

Abstract: Ozonolysis is a major tropospheric removal mechanism for unsaturated hydrocarbons and proceeds via "Criegee intermediates"--carbonyl oxides--that play a key role in tropospheric oxidation models. However, until recently no gas-phase Criegee intermediate had been observed, and indirect determinations of their reaction kinetics gave derived rate coefficients spanning orders of magnitude. Here, we report direct photoionization mass spectrometric detection of formaldehyde oxide (CH(2)OO) as a product of the reaction of CH(2)I with O(2). This reaction enabled direct laboratory determinations of CH(2)OO kinetics. Upper limits were extracted for reaction rate coefficients with NO and H(2)O. The CH(2)OO reactions with SO(2) and NO(2) proved unexpectedly rapid and imply a substantially greater role of carbonyl oxides in models of tropospheric sulfate and nitrate chemistry than previously assumed.