Absolute rate of the reaction of atomic hydrogen with acetaldehyde

Abstract

Absolute rate constants for the reaction of hydrogen atoms with acetaldehyde were obtained over the temperature range 298-500 K using the flash photolysis-resonance fluorescence technique. The rate constants gave the Arrhenius expression k = (2.23 ±0.39)X 10-11 exp( -3300± 120/ 1.987 T) cm 3 molecule-Is-I. Independent experiments with a discharge flow system employing resonance fluorescence detection of H gave a room temperature rate constant in agreement with this equation. These results are discussed and comparisons are made with previous work and theoretical predictions.

Temperature dependence of rate constants for the reaction of atomic oxygen with hydrogen chloride

“…= 1.9 f 0.2 over the limited temperature range of 298-360 K. Thus HC1 appears to be slightly less effective as a third body in reaction (2) than H2O ( a = 2.9) [17], but more effective than SFG ( a = 1.2) [17]. The results for HC1 are similar to those reported for the rare gases [15] and nitrogen [21] as third bodies in reaction (2), in as much as they give very similar temperature dependences for k.2 (that is, a is independent of temperature), and which were interpreted in terms of an energy transfer mechanism [15]. If a radical molecule complex mechanism [22] were to occur for M = HC1, the temperature dependence of k2 would be different, and probably more negative, than for M = N2O…”

Shock‐tube and modeling study of acetaldehyde pyrolysis and oxidation

“…3a. Also, even if reactions (1)-(3) were used as the initiation reaction and various rate-constant expressions for reactions, (1)-(3), (5), (7), and (17) were assumed, the UV-absorption profiles at 200 nm and the IRemission profiles at 4.68 µm were not reproduced and the calculated values were much smaller than observed ones, as shown in Figs. 3a and 4a; the UVabsorption profiles and the IR-emission profiles largely depended on ketene concentration produced, as shown cm 3 mol −1 s −1 was assumed for reaction (12).…”

“…The effective heating times at each temperature are 2850 µs (1000 K), 2630 µs (1100 K), 2410 µs (1200 K), 2190 µs (1300 K), 1970 µs (1400 K), 1750 µs (1500 K), 1520 µs (1600 K), and 1300 µs (1700 K). ---: calculated with the mechanism described in Table XII; · · · · · · · · · · · · · · ·: reactions (1), (5), (7), and (17) and the rate constant values reported by Baulch et al [37,38]; ------: reactions (1), (5), (7), (17) and CH 3 CHO + CHO = CH 3 CO + CH 2 O and the rate constant values reported by Dagaut et al [14]; -·-·-·-·: calculated with the mechanism described in Table XII •: observed at 1329 K, 1.97 atm, 1.81 × 10 −5 mol/cm 3 ; : observed at 1477 K, 2.37 atm, 1.96 × 10 −5 mol/cm 3 ; , observed at 1589 K, 2.68 atm, 2.05 × 10 −5 mol/cm 3 ;---: calculated with the mechanism described in Table XII; · · · · · · · · · reactions (1), (5), (7), and (17) and the rate constant values reported by Baulch et al [37,38]; -·-·-·-·-: calculated with the mechanism described in Table XII decreased with time. The profiles were analyzed using an equation A t = log (I f /I t ) / log (I f /I 0 ), where I f was the signal voltage corresponding to the full intensity and I 0 and I t were the signal voltages corresponding to the absorption intensities at the reflected shock front (t = 0) and at time t, respectively.…”

“…1a, 2a, 3a, and 4a; reactions (1)- (17) shown in Table XII were exchanged to reactions (1), (5), (7), and (17) and the rate constant expressions reported by Baulch et al [37,38]. In the pyrolysis, the simulated findings can reproduce the observed C 2 H 6 , C 2 H 4 , and C 2 H 2 yields within experimental error, but CO and CH 4 yields are larger than those observed, as shown in Fig.…”

“…The proposed rate constant expression was k 1 = 3.0 × 10 14 exp(−80.0 kcal/RT) s −1 . Substantially, all the rate constants of reactions (5), (7), and (17) reported were evaluated at low temperatures below 1000 K [5][6][7][8][9][10][11]. Only a few evaluation and detailed discussion for them have been done at high temperatures though they are very important to learn the combustion mechanism above 1000 K.…”