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High‐temperature pyrolysis of acetaldehyde
Author(s) -
Colket M. B.,
Naegeli D. W.,
Glassman I.
Publication year - 1975
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550070207
Subject(s) - chemistry , ketene , acetaldehyde , pyrolysis , reaction rate constant , analytical chemistry (journal) , nitrogen , kinetics , medicinal chemistry , ethanol , organic chemistry , physics , quantum mechanics
High‐temperature (>1000°K) pyrolysis of acetaldehyde (∼1% in an atmosphere of pure nitrogen) was examined in a turbulent flow reactor which permits accurate determination of the spatial distribution of the stable species. Results show that the products in order of decreasing importance are CO, CH 4 , H 2 , C 2 H 6 , and C 2 H 4 . Rates of formation were consistent with the Rice–Herzfeld mechanism by including reactions to explain C 2 H 4 formation and the possible presence of ketene. A steady‐state treatment of the complete mechanism indicates that the overall reaction order decreases from \documentclass{article}\pagestyle{empty}\begin{document}$ \frac{3}{2} $\end{document} to 1, which is supported by the new experimental data. Using earlier low‐temperature results, the rate constant for the reaction CH 3 CHO → CH 3 + CHO (1) was found as k 1 =10 15.85±0.21 exp (−81,775±1000/ RT ) sec −1 . Also, data for the ratio of rate constants for reactions CH 3 CHO + CH 3 → CH 4 + CH 3 CO (4) and 2CH 3 → C 2 H 6 (6) were fitted to the empirical expression k 4 / k 6 1/2 =10 −13.89±0.03 T 6.1 exp(−1720±70/ RT ) (cm 3 /mole·sec) 1/2 and causes for the curvature are discussed. The noncatalytic effect of oxygen on acetaldehyde pyrolysis at high temperature is explained.