Theoretical and experimental studies of the diketene system: Product branching decomposition rate constants and energetics of isomers
✍ Scribed by Binh Bui; Ti Jo Tsay; M. C. Lin; C. F. Melius
- Publisher
- John Wiley and Sons
- Year
- 2007
- Tongue
- English
- Weight
- 401 KB
- Volume
- 39
- Category
- Article
- ISSN
- 0538-8066
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✦ Synopsis
Abstract
The kinetics and mechanism for the thermal decomposition of diketene have been studied in the temperature range 510–603 K using highly diluted mixtures with Ar as a diluent. The concentrations of diketene, ketene, and CO~2~ were measured by FTIR spectrometry using calibrated standard mixtures. Two reaction channels were identified. The rate constants for the formation of ketene (k~1~) and CO~2~ (k~2~) have been determined and compared with the values predicted by the Rice–Ramsperger–Kassel–Marcus (RRKM) theory for the branching reaction. The first‐order rate constants, k~1~ (s^−1^) = 10^15.74 ± 0.72^ exp(−49.29 (kcal mol^−1^) (±1.84)/RT) and k~2~ (s^−1^) = 10^14.65 ± 0.87^ exp(−49.01 (kcal mol^−1^) (±2.22)/RT); the bulk of experimental data agree well with predicted results. The heats of formation of ketene, diketene, cyclobuta‐1,3‐dione, and cyclobuta‐1,2‐dione at 298 K computed from the G2M scheme are −11.1, −45.3, −43.6, and −40.3 kcal mol^−1^, respectively. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 580–590, 2007