ISSN:
0538-8066
Keywords:
Chemistry
;
Physical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The mechanism for neopentane (NpH) pyrolysis in the absence and presence of additives isobutene, HCl and HBr, in the temperature range 750-800 K, has been reinvestigated with the aid of computer simulation and sensitivity analysis techniques. With best values assigned to all rate constants in the kinetic chain, a basic mechanism comprising 18 reversible reactions involving 19 atomic, radical, and molecular species has been used to simulate pure neopentane pyrolysis data. Predictions of major and minor product yields provided quantitative agreement with experimental data against which the model was tested. The mechanism was supplemented by additional species and reactions in order to simulate experimental neopentane pyrolysis data in the presence of HCl and HBr additives. An apparent discrepancy between a recent direct measurement of k5, the rate constant for thermal decomposition of the neopentyl radical [1], and that reported from studies of neopentane pyrolysis in the presence and absence of HCl [2], has been identified as being due to the use of an incomplete mechanism in the latter determination. Simulations of hydrogen halide catalyzed pyrolyses exhibit a high sensitivity to the thermochemical parameters associated with the neopentyl radical (Np). The influence of uncertainties in ΔH°f(Np) and S°298(Np) are evaluated and lead to suggested values ΔH°f(Np) = 8.7 ± 0.8 kcal mol-1 and S°298(Np) = 78.8 ± 1.0 cal mol-1 K-1. © 1993 John Wiley & Sons, Inc.
Additional Material:
8 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/kin.550251107
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