Rate coefficients of hydroxyl radical reaction with dimethyl ether over a temperature range of 257–333 K

2018 ◽  
Vol 706 ◽  
pp. 558-563 ◽  
Author(s):  
Monali Kawade ◽  
Asmita Sharma ◽  
D. Srinivas ◽  
Ankur Saha ◽  
Hari P. Upadhyaya ◽  
...  
Keyword(s):  
Hydroxyl Radical ◽  
Dimethyl Ether ◽  
Radical Reaction ◽  
Rate Coefficients ◽  
Temperature Range

Rate Coefficients of Hydroxyl Radical Reaction with 1-Chlorocyclopentene over a Temperature Range of 262-335 K

2021 ◽  
pp. 138816
Author(s):  
Asmita Sharma ◽  
Mohini P. Walavalkar ◽  
Anmol Virmani ◽  
Ankur Saha ◽  
Sumana SenGupta ◽  
...  
Keyword(s):  
Hydroxyl Radical ◽  
Radical Reaction ◽  
Rate Coefficients ◽  
Temperature Range

scholarly journals Atmospheric reaction of hydrazine plus hydroxyl radical

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hamed Douroudgari ◽  
Morteza Vahedpour ◽  
Fahime Khouini
Keyword(s):  
Hydroxyl Radical ◽  
Rate Constants ◽  
Reaction Pathway ◽  
Radical Reaction ◽  
Basis Sets ◽  
Rate Coefficients ◽  
Stationary Points ◽  
Main Reaction ◽  
Partition Functions ◽  
Oh Radicals

AbstractUnderstanding the mechanism of hydrazine oxidation reaction by OH radical along with the rate constants of all possible pathways leads to explain the fate of hydrazine in the atmosphere. In this article, the comprehensive mechanisms and kinetics of the hydrazine plus hydroxyl radical reaction have been investigated theoretically at different temperatures and pressures. To achieve the main goals, a series of high levels of quantum chemical calculations have been widely implemented in reliable channels of the H-abstraction, SN2, and addition/elimination reactions. The energy profile of all pathways accompanied by the molecular properties of the involved stationary points has been characterized at the MP2, M06-2X, and CCSD(T)/CBS levels. To estimate accurate barrier energies of the H-abstraction channels, large numbers of the CCSD (T) calculations in conjunction with various augmented basis sets have been implemented. The direct dynamic calculations have been carried out using the validated M06-2X/maug-cc-pVTZ level, and also by the CCSD(T) (energies) + MP2 (partition functions) level. The pressure-dependent rate constants of the barrierless pathways have been investigated by the strong collision approach. Therefore, the main behaviors of the N2H4 + OH reaction have been explored according to the influences of temperature and pressure on the computed rate coefficients within the well-behaved theoretical frameworks of the TST, VTST, and RRKM theories. It has been found that the H-abstraction mechanism (to form N2H3) is dominant relative to the SN2 reaction and OH-addition to the N center of N2H4 moiety (to form H2NOH + NH2). The computed high pressure limit rate constant of the main reaction pathway, k(298.15) = 7.31 × 10–11 cm3 molecule−1 s−1, has an excellent agreement with the experimental value (k (298.15) = (6.50 ± 1.3) × 10–11 cm3 molecule−1 s−1) recommended by Vaghjiani. Also, the atmospheric lifetime of hydrazine degradation by OH radicals has been demonstrated to be 32.80 to 1161.11 h at the altitudes of 0–50 km. Finally, the disagreement in the calculated rate constants between the previous theoretical study and experimental results has been rectified.

scholarly journals A combined experimental and theoretical study of reactions between the hydroxyl radical and oxygenated hydrocarbons relevant to astrochemical environments

2014 ◽  
Vol 16 (8) ◽  
pp. 3466-3478 ◽  
Author(s):  
R. J. Shannon ◽  
R. L. Caravan ◽  
M. A. Blitz ◽  
D. E. Heard
Keyword(s):  
Hydroxyl Radical ◽  
Dimethyl Ether ◽  
Low Temperatures ◽  
Theoretical Study ◽  
Rate Coefficients ◽  
Oxygenated Hydrocarbons ◽  
P Rate

Rate coefficients for the reactions of the hydroxyl radical with acetone and dimethyl ether increase dramatically at very low temperatures.

scholarly journals Experimental and computational kinetics investigations for the reactions of Cl atoms with series of unsaturated ketones in gas phase

2017 ◽  
Author(s):  
Siripina Vijayakumar ◽  
Avinash Kumar ◽  
Balla Rajakuma
Keyword(s):  
Gas Phase ◽  
State Theory ◽  
Rate Coefficients ◽  
Gas Phase Reactions ◽  
Temperature Dependent ◽  
Unsaturated Ketones ◽  
Temperature Range ◽  
Computational Calculations ◽  
Temperature Rate ◽  
Cl Atoms

Abstract. Temperature dependent rate coefficients for the gas phase reactions of Cl atoms with 4-hexen-3-one and 5-hexen-2-one were measured over the temperature range of 298–363 K relative to 1-pentene, 1,3-butadiene and isoprene. Gas Chromatography (GC) was used to measure the concentrations of the organics. The derived temperature dependent Arrhenius expressions are k4-hexen-3-one+Cl (298–363 K) = (2.82 ± 1.76)×10−12exp [(1556 ± 438)/T] cm3 molecule−1 s−1 and k5-hexen-2-one+Cl (298–363 K) = (4.6 ± 2.4)×10−11exp[(646 ± 171)/T] cm3 molecule−1 s−1. The corresponding room temperature rate coefficients are (5.54 ± 0.41)×10−10 cm3 molecule−1 s−1 and (4.00 ± 0.37)×10−10 cm3 molecule−1 s−1 for the reactions of Cl atoms with 4-hexen-3-one and 5-hexen-2-one respectively. To understand the mechanism of Cl atom reactions with unsaturated ketones, computational calculations were performed for the reactions of Cl atoms with 4-hexen-3-one, 5-hexen-2-one and 3-penten-2-one over the temperature range of 275–400 K using Canonical Variational Transition state theory (CVT) with Small Curvature Tunneling (SCT) in combination with CCSD(T)/6-31+G(d, p)//MP2/6-311++G(d, p) level of theory. Atmospheric implications, reaction mechanism and feasibility of the title reactions are discussed in this manuscript.

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