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Elementary reaction
About: Elementary reaction is a research topic. Over the lifetime, 2972 publications have been published within this topic receiving 76110 citations.
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TL;DR: It is concluded that the reaction mechanism is the main indicator for the reaction rate for CH2OO + acid reactions, with acidity only of secondary influence.
Abstract: The reaction of CH2OO, the smallest carbonyl oxide (Criegee intermediate, CI), with several acids was investigated using the CCSD(T)/aug-cc-pVTZ//M06-2X/aug-cc-pVTZ quantum chemical method, as well as microvariational transition state theory and RRKM master equation theoretical kinetic methodologies. For oxoacids HNO3 and HCOOH, a 1,4-insertion mechanism allows for barrierless reactions with high rate coefficients, in agreement with literature experimental data. This mechanism relies on the presence of a double bond in the α-position to the acidic OH group. We predict that reactions of CI with enols will likewise have high rate coefficients, proceeding through a similar mechanism. The hydracid HCl was found to react through a less favorable 1,2-insertion reaction, leading to lower rate coefficients, again in good agreement with the literature. We conclude that the reaction mechanism is the main indicator for the reaction rate for CH2OO + acid reactions, with acidity only of secondary influence. At room temperature and 1 atm the main product for all reactions was found to be the thermalized hydroperoxide initial adduct, with minor yields of fragmentation products. One of the product channels characterized is a novel reaction path involving intramolecular H-abstraction after a roaming reaction in the OH + product radical complex formed by the dissociation of the hydroperoxide adduct; this channel is the lowest fragmentation route for some of the reactions studied.
65 citations
TL;DR: Different phosphines have been used to modulate the thermodynamic and kinetic parameters of the cation exchange reaction to synthesize complex semiconductor nanostructures and show potential to precisely tune the crystallinity and composition of metal/semiconductor core-shell and doped nanocrystals.
Abstract: Phosphine-initiated cation exchange is a well-known inorganic chemistry reaction. In this work, different phosphines have been used to modulate the thermodynamic and kinetic parameters of the cation exchange reaction to synthesize complex semiconductor nanostructures. Besides preserving the original shape and size, phosphine-initiated cation exchange reactions show potential to precisely tune the crystallinity and composition of metal/semiconductor core-shell and doped nanocrystals. Furthermore, systematic studies on different phosphines and on the elementary reaction mechanisms have been performed.
64 citations
TL;DR: A reaction scheme including detailed rate expressions for O and N atom recombination on the surface of re-entry vehicles is established, consisting of elementary reaction steps, and a quantitative agreement is achieved between recombination coefficients resulting from the numerical computations and those calculated from experiments.
Abstract: In connection with recombination coefficients derived from experimental data described in the literature, a reaction scheme including detailed rate expressions for O and N atom recombination on the surface of re-entry vehicles is established, consisting of elementary reaction steps. To validate the reaction mechanism derived, surface chemistry and fluid mechanical processes are coupled assuming a one-dimensional stagnation flow field. A quantitative agreement is achieved between recombination coefficients resulting from the numerical computations and those calculated from experiments. The temperature dependence of the recombination coefficient is explained by elementary reaction steps. Furthermore, the reaction scheme established is implemented in a two-dimensional Navier-Stokes code computing the re-entry flow around a simple geometry to show the importance ofa detailed modeling of surface reactions.
64 citations
TL;DR: In this article, the authors exploit an experimental approach which, by taking advantage of the correlated information of coincident product pairs, allows them to peel off judiciously the intrinsic complications of a six-atom reaction, extracting the underlying backbone of three-atom dynamics.
Abstract: To unravel the “extra-atom” complexity of the title reaction, we exploit an experimental approach which, by taking advantage of the correlated information of coincident product pairs, allows us to peel off judiciously the intrinsic complications of a six-atom reaction, extracting the underlying backbone of three-atom dynamics. Examining the collisional energy dependencies of the pair-correlated attributes for a given state(s) of CD3 products from the title reaction, several of major observations can qualitatively be understood, whereas others await further theoretical investigations. An intriguing possibility for the existence of reactive resonances in this six-atom reaction is surmised.
64 citations
TL;DR: In this paper, a two-step reduced reaction mechanism was constructed to simulate the oxidation process of methanol in supercritical water and H2O. The mechanism was validated over a temperature range of 726 to 873 K, a fuel concentration range of 0.001 to 0.004 mole/L, and at a pressure of 246 bar.
64 citations