Very low-pressure pyrolysis (VLPP) of penta-1,3-dienes. Kinetics of the unimolecular 1,4-hydrogen elimination from cis-penta-1,3-diene
✍ Scribed by Tam T. Nguyen; Keith D. King
- Publisher
- John Wiley and Sons
- Year
- 1982
- Tongue
- English
- Weight
- 323 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0538-8066
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✦ Synopsis
Abstract
The thermal unimolecular reactions of cis‐ and trans‐penta‐1,3‐diene (c‐PTD and t‐PTD) have been studied over the temperature range of 1002–1235 K using the technique of very low‐pressure pyrolysis (VLPP). c‐PTD decomposes via 1,4‐hydrogen elimination analogous to that previously reported for cis‐but‐2‐ene. RRKM calculations incorporating a six‐center transition state show that the experimental rate constants are consistent with the following high‐pressure rate expression at 1100 K:
where θ = 2.303__RT__ kcal/mol, and the A factor was assumed to be the same as that for cis‐but‐2‐ene. The activation energy is in excellent agreement with that obtained for cis‐but‐2‐ene. t‐PTD also undergoes decomposition by H~2~ elimination presumably via the prior rapid isomerization to c‐PTD the results are in exact agreement with those for c‐PTD.