Free Radicals by Mass Spectrometry: Xxxii. Thermal Decomposition of Cyclopentyl Radicals

Abstract

At low pressures and elevated telnperatures cyclopentyl radicals are found to dissociate mainly by two modes of reaction: about 34% by loss of H atom to form cyclopentene, and about 66% by a C-C bond rupture to form ethylene and allyl radicals. Under the conditions employed no evidence for a third possible mode, the loss of H t to form cyclopentenyl radical, could be found. I t is estimated that an incidence of 2Yo of the latter could have been detected.

Kinetics and Mechanism on a Reaction of Allyl Radical with Ethylene

“…Reactions (11) and (12) may exist, but not as main termination reactions because of three times as large quantity of C5 products formations as that of C4 products formations.…”

Mass Spectrometry

“…A variety of studies have been made on unimolecular thermal decompositions in flow reactors. Particular reactors are described and applied to the decomposition of trioxane (346), cyclopentyl radicals (836), ethyl nitrite (209), azomethane (1110), and NH4CIO4 (445), the formation of benzvne (82) and its dimerization (944), and the detection of BH3, BH2, and polymeric species (63, 335, 983), and the pyrolysis of B2H6 and polyboranes. Also studied was the stability of 02F2 (692), addition of CH3 • to B2C2H3C1 (488), and the mercury-photosensitized decompositions of C2H4 (548), 2-C4Hs (549) and alkynes (547).…”

A Shock Tube Study of H Atom Addition to Cyclopentene

“…Addition of H to cyclopentene forms the cyclopentyl radical, which at higher temperatures is wellestablished to undergo ring opening and ensuing decomposition to ethene and allyl radical [5][6][7][8][9][10][11][12][13]. Ring opening competes with the re-ejection of hydrogen atom, the kinetics of which is related to H addition through detailed balance.…”