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The kinetics and thermochemistry of the gas phase reaction of cyclopentadiene and iodine. Relevance to the heat of formation of cyclopentadienyl iodide and cyclopentadienyl radical
Author(s) -
Furuyama Shozo,
Golden David M.,
Benson Sidney W.
Publication year - 1971
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.550030305
Subject(s) - cyclopentadiene , cyclopentadienyl complex , chemistry , equilibrium constant , thermochemistry , reaction rate constant , arrhenius equation , iodide , activation energy , yield (engineering) , atmospheric temperature range , standard enthalpy of formation , reaction rate , kinetics , inorganic chemistry , thermodynamics , organic chemistry , catalysis , physics , quantum mechanics
The rate of the reaction of cyclopentadiene with iodine has been followed spectrophotometrically over the temperature range 171.7° to 276.5°C. The reaction first proceeds almost to the point of equilibrium with cyclopentadienyl iodide and HI, although the final products are fulvalene and HI. Equilibrium constants obtained are those predicted by bond additivity. A third‐law value of δ H 0 f 298 (c‐C 5 H 5 I,g) = 49 kcal/mole is obtained. Rate studies of the reaction up to the iodide equilibrium, yield values for the rate constant. Uncertainty in the Arrhenius parameters, as well as doubts as to the applicability of the usual assumption that E 3 = 1 ± 1 kcal/mole, make difficult an evaluation of total cyclopentadienyl stabilization energy (TSE) from these data. However, the value is probably 15 < TSE < 20.