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Product Study (product + study)
Selected AbstractsQuenching of Singlet Oxygen by Tertiary Aliphatic Amines.HELVETICA CHIMICA ACTA, Issue 10 2006Products, Structural Effects on Rates Abstract A kinetic and product study of the reaction of a series of , -methyl-substituted N -methylpiperidines with thermally generated 1O2 in MeCN was carried out. It was found that as the number of , -methyl groups (Me in , -position relative to the N-atom) increases, the rate of 1O2 quenching (physical plus chemical) slightly decreases. This finding shows that, with respect to the reaction rate, steric effects are much more important than electronic effects as the latter should have produced the opposite result. The opposite outcome was instead found for the chemical quenching that leads to the N -demethylation products and N -formyl derivatives. The same trend was observed for the ratio between N -demethylation and formation of the N -formyl derivatives (NH/NCHO ratio). All these results are consistent with the mechanism reported in Scheme,1 where an exciplex is first formed that by a H-atom transfer process produces an , -amino-substituted C-radical. The latter forms the product of N -demethylation by one electron oxidation, or affords the N -formyl derivative by radical coupling (Scheme,1). Similar results were obtained with N,N -dimethylcyclohexanamine. However, this ,acyclic' amine exhibited behaviors quite distinct from those of the N -methylpiperidines series, with respect to reaction rate, extent of chemical quenching, and NH/NCHO ratio. [source] Kinetic and product study of the gas-phase reaction of sabinaketone with OH radicalINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 7 2007Nathalie Carrasco Sabinaketone is one major photooxidation product of sabinene, an important biogenic volatile organic compound. This article provides the first product study and the second rate constant determination of its reaction with OH radicals. Experiments were investigated under controlled conditions for pressure and temperature in the LISA indoor simulation chamber using FTIR spectrometry. Kinetic study was carried out at 295 ± 2 K and atmospheric pressure using the relative rate technique with isoprene as the reference compound. The rate constant was found to be ksabinaketone + OH = (7.1 ± 1.0) × 10,12 molecule,1 cm3 s,1. Acetone and formaldehyde were detected as products of the reaction with the respective yields of Racetone = 0.9 ± 0.2 and RHCHO = 1.2 ± 0.3. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 415,421, 2007 [source] A kinetic and product study of reaction of chlorine atom with CH3CH2ODINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 11 2004Mary A. Crawford The reaction of atomic chlorine with CH3CH2OD has been examined using a discharge fast flow system coupled to a mass spectrometer combined with the relative rate method (RR/DF/MS). At 298 ± 2 K, the rate constant for the Cl + CH3CH2OD reaction was determined using cyclohexane as a reference and found to be k3 = (1.13 ± 0.21) × 10,10 cm3 molecule,1 s,1. Mass spectral studies of the reaction products resulted in yields greater than 97% for the combined hydrogen abstraction at the , and , sites (3a + 3b) and less than 3% at the hydroxyl site (3c). As a calibration of the apparatus and the RR/DF/MS technique, the rate constant of the Cl + CH3CH2OH reaction was also determined using cyclohexane as the reference, and a value of k2 = (1.05 ± 0.07) × 10,10 cm3 molecule,1 s,1 was obtained at 298 ± 2 K, which was in excellent agreement with the value given in current literature. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 584,590, 2004 [source] | ||||||||||