An experimental and computational study of the unimolecular-decay reaction of diethyl-substituted Criegee intermediate (CH)COO.

We have performed direct kinetic measurements to determine the thermal unimolecular-decay rate coefficient of (CH)COO as a function of temperature (223-296 K) and pressure (4-100 torr) using time-resolved UV-absorption spectroscopy. The stabilised (CH)COO Criegee intermediate was produced by photolysing 3-bromo-3-iodopentane ((CH)CIBr) with 213 nm radiation in the presence of O. We performed quantum-chemistry calculations and master-equation simulations to complement the experimental work.

Direct Kinetic Measurements of a Cyclic Criegee Intermediate; Unimolecular Decomposition of (CH)COO.

We report the first direct kinetic measurements of a cyclic stabilized Criegee Intermediate. We have measured the unimolecular reaction rate coefficient of cyclohexanone oxide ((CH)COO) in the temperature 213-296 K and pressure 7-50 Torr ranges using absorption spectrometry. The (CH)COO was produced by the photolysis of (CH)CIBr at 213 nm in the presence of O.

Putative NAD(P)-Binding Rossmann Fold Protein Is Involved in Chitosan-Induced Peroxidase Activity and Lipoxygenase Expression in .

Oxidative burst, the rapid production of high levels of reactive oxygen species in response to external stimuli, is an early defense reaction against pathogens. The fungal elicitor chitosan causes an oxidative burst in the moss (formerly ), mainly due to the peroxidase enzyme Prx34. To better understand the chitosan responses in , we conducted a screen of part of a mutant collection to isolate plants with less peroxidase activity than wild-type (WT) plants after chitosan treatment.

An experimental and computational study of the reaction between pent-3-en-2-yl radicals and oxygen molecules: switching from pure stabilisation to pure decomposition with increasing temperature.

We have used laser-photolysis-photoionization mass spectrometry, quantum chemical calculations, and master equation simulations to investigate the kinetics of the reaction between (/)-pent-3-en-2-yl a resonance-stabilised hydrocarbon radical, and molecular oxygen. The time-resolved experiments were performed over a wide temperature range (240-750 K) at relatively low pressures (0.4-7 Torr) under pseudo-first-order conditions (excess [O]).

Solving the discrepancy between the direct and relative-rate determinations of unimolecular reaction kinetics of dimethyl-substituted Criegee intermediate (CH)COO using a new photolytic precursor.

We have performed direct kinetic measurements of the thermal unimolecular reaction of (CH)COO in the temperature range 243-340 K and pressure range 5-350 Torr using time-resolved UV-absorption spectroscopy. We have utilized a new photolytic precursor, 2-bromo-2-iodopropane ((CH)CIBr), which photolysis at 213 nm in the presence of O produces acetone oxide, (CH)COO. The results show that the thermal unimolecular reaction is even more important main loss process of (CH)COO in the atmosphere than direct kinetic studies have suggested hitherto.