To provide benchmark information needed to develop kinetic models of the combustion and pyrolysis of hydrocarbon ring structures, we have used the single pulse shock tube technique to study the kinetics of H atom addition to cyclopentene at 863 K to 1167 K and pressures of 160 kPa to 370 kPa. Addition of H to the pi bond leads to the cyclopentyl radical, which rapidly decomposes to ethene and allyl radical. Rate constants for the overall process were determined relative to a reference reaction via post-shock GC/FID/MS monitoring of products. A Transition- State-Theory/Rice-Ramsberger-Kassel-Marcus (TST/RRKM) model has been applied in conjunction with evaluated literature data to convert the primary measurements to a high pressure limiting rate expression for H addition. Results are compared with related systems. Near 1000 K, our data require a minimum value of 1.5 for branching between beta C-C and C-H bond scission in cyclopentyl radicals to maintain established trends in H addition rates. This minimum is consistent with a branching value of about 3 that we determined in previous experiments, but conflicts with much smaller values derived by current computations and those used in recent kinetics models to describe jet-stirred reactor studies of cyclopentane combustion.
Combustion Institute Eastern States Spring Meeting
March 4-7, 2018
State College, PA
Kinetics, Fuels, Cyclopentyl, Shock Tube, RRKM