1-Dodecylpyrene (DDP) pyrolysis at 375-425 °C for 10-180 min led to 1-methylpyrene, 1-undecene, 1-ethylpyrene, and n-decane as the major products at low conversions. At higher conversions, pyrene and n-dodecane were the major products. Minor products included a series of n-alkanes, a-olefins, and alkyl-substituted pyrenes. The variations of the products' molar yields with substrate conversion suggested that the reaction pathways operative at low DDP conversions were analogous to those observed in alkylbenzene pyrolysis. However, a different pathway involving facile and apparently autocatalytic cleavage of the strong aryl-alkyl C-C bond was dominant at moderate and high DDP conversions. The kinetics of DDP disappearance were also consistent with autocatalytic decomposition. The present results suggest that thermal cleavage of aryl-alkyl C-C bonds in heavy hydrocarbon resources such as petroleum residua, asphaltenes, and coal might be more prevalent than previously thought.The majority of processes for converting and upgrading heavy hydrocarbon resources such as petroleum residua, asphaltenes, and coal, though nominally catalytic, operate at elevated temperatures where purely thermal reactions can contribute to the observed product spectra and kinetics. In fact, recent kinetics studies of direct coal liquefaction (Gollakota et al., 1985) and asphaltene hydroprocessing (Savage et al., 1988

Insights from the venerable Trouton’s Rule have been used to guide the development of an applied-thermodynamic method for the estimation, correlation, and evaluation of pure-component vapor pressure. Trouton’s Rule very simply and succinctly states that the entropy of vaporization of fluids at their normal boiling point is a constant (≈10.5 times the gas constant). Detailed evaluation of the data for many families of chemical compounds reveals the subtle patterns of departures from the rule, and facilitates the development of a useful new correlation. Several examples are presented to demonstrate the value of the new correlation to estimate, correlate, extrapolate, and evaluate vapor-pressure data, and to understand the patterns of vapor-pressure behavior. The methodology provides a guide for the development of thermodynamic correlations, and the resulting correlations are expected to be useful for the practice of applied thermodynamics.

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