Reaction of ketenes with atomic oxygen

Abstract

Rate constants for the reaction of atomic oxygen with ketene, and methyl, ethyl, and dimethyl ketene were measured over a temperature range of 230--449 K using the pulse radiolysis resonance absorption system. Over the temperature range of the experiments, the rate data could be fitted by Arrhenius expressions:(4.79± l.31)X 1O-'2exp[(494.9± 163.2 cal mol-')IRT]; 0 + (C 2 H s )CHCO, (5.36±0.83)X 1O-'2exp[(444.6±94.0 cal mol-')lRT]; 0 + (CH,hCCO, (5.92 ±0.94) X 1O-'2exp[(1131 ±85 cal mol-')IRT]; in units of cm' molecule-' s-'.The rate constants at room temperature were also determined using a discharge-flow system coupled toa photoionization mass spectrometer. Rate constants obtained are 0.D43±0.D4, 1.l6±0.13, l.36±0.l1, and 6.04±0.64X 10-11 cm-' molecule-' s-, for CH 2 CO, (CH,)CHCO, (C 2 H s )CHCO, and (CH 3 hCCO, respectively. Several reaction products were analyzed by the photoionization mass spectrometer.

Theoretical Study on the Reaction Mechanism of Ketene CH2CO with Isocyanate NCO Radical

“…The kinetics and products of the reactions of CH 2 CO with H, F, Cl, OH, NCO, and CN have been reported experimentally. [15][16][17][18][19][20][21] But relative to the experimental studies, the knowledge on the theoretical studies for CH 2 CO is rare limited. Up to now, only the reaction mechanisms and product distribution of CH 2 CO with Cl, 22,23 F, 24 and NCO 25,26 have been investigated theoretically.…”

Theoretical investigation on the radical-neutral reaction mechanism of CP with CH2CO and the structural nature of several low-lying intermediates

“…Its reactions with some atoms and radicals, such as H, O, F, Cl, OH, CN, and NCO, in the gas phase are of considerable importance in combustion of hydrocarbons and received a number of experimental investigations regarding their reaction kinetics and product distributions [1][2][3][4][5][6][7][8][9][10]. Furthermore, the reactions of CH 2 CO with Cl, CN, NCO, and H have been also investigated theoretically using quantum chemistry techniques [11][12][13][14][15][16][17].…”

DFT investigation of the mechanism of CH2CO + O(3P) reaction

“…The kinetics and products of the reactions of CH 2 CO with H, O( 3 P), F, Cl, OH, CN, and NCO have been investigated experimentally [1][2][3][4][5][6][7][8][9][10][11][12][13]. Carr et al [3], Washida et al [4], and DeMore et al [5] studied the reaction of CH 2 CO with O, and the following possible channels were found: DeMore et al [5] concluded that P1: CH 2 ϩ CO 2 accounts for 60% of all the products, and path1 dominates the reaction. Washida et al [4] provided support for the importance of path1 and path3 in the title reaction.…”