Shock‐tube and modeling study of acetaldehyde pyrolysis and oxidation

Abstract

Abstract Pyrolysis and oxidation of acetaldehyde were studied behind reflected shock waves in the temperature range 1000–1700 K at total pressures between 1.2 and 2.8 atm. The study was carried out using the following methods, (1) time‐resolved IR‐laser absorption at 3.39 μm for acetaldehyde decay and CH‐compound formation rates, (2) time‐resolved UV absorption at 200 nm for CH 2 CO and C 2 H 4 product formation rates, (3) time‐resolved UV absorption at 216 nm for CH 3 formation rates, (4) time‐resolved UV absorption at 306.7 nm for OH radical formation rate, (5) time‐resolved IR emission at 4.24 μm for the CO 2 formation rate, (6) time‐resolved IR emission at 4.68 μm for the CO and CH 2 CO formation rate, and (7) a single‐pulse technique for product yields. From a computer‐simulation study, a 178‐reaction mechanism that could satisfactorily model all of our data was constructed using new reactions, CH 3 CHO (+M) → CH 4 + CO (+M), CH 3 CHO (+M) → CH 2 CO + H 2 (+M), H + CH 3 CHO → CH 2 CHO + H 2 , CH 3 + CH 3 CHO → CH 2 CHO + CH 4 , O 2 + CH 3 CHO → CH 2 CHO + HO 2 , O + CH 3 CHO → CH 2 CHO + OH, OH + CH 3 CHO → CH 2 CHO + H 2 O, HO 2 + CH 3 CHO → CH 2 CHO + H 2 O 2 , having assumed or evaluated rate constants. The submechanisms of methane, ethylene, ethane, formaldehyde, and ketene were found to play an important role in acetaldehyde oxidation. © 2007 Wiley Periodicals, Inc. 40: 73–102, 2008