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Energy transfer in unimolecular reactions at high temperatures
Author(s) -
Barnard J. A.,
Parrott T. K.
Publication year - 1977
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.550090308
Subject(s) - chemistry , diluent , cyclopropane , cyclobutane , thermodynamics , shock tube , cyclohexene , inert , shock (circulatory) , limiting , photochemistry , shock wave , organic chemistry , catalysis , ring (chemistry) , medicine , mechanical engineering , physics , engineering
The application of modern theories of energy transfer to unimolecular reactions taking place at very high temperatures is discussed. It is shown that the efficiency of energy transfer for both reactant–reactant and reactant–inert diluent collisions may be substantially smaller than the values determined experimentally at lower temperatures. Consequently at high temperatures unimolecular falloff effects, particularly in some shock‐tube measurements, may be greater than has been believed hitherto. The application of these calculations to the unimolecular reactions of cyclopropane, cyclobutane, and cyclohexene at temperatures around 1300°K is discussed, and it is shown that under shock‐tube conditions the apparent first‐order rate coefficient may be at least ten times less than the high‐pressure limiting value.