Advanced thermally stable jet fuels. Technical progress report, January 1996--March 1996

A reactive structure index was developed to correlate the molecular structures of saturated hydrocarbons with their reactivities using a linear group contribution method. The index is composed of several sub-indices determined from the structure, including carbon group indices, ring index, and conformation index. The effects on decomposition of ring structure, side-chain length, steric isomers, and branching were examined. Good correlations were obtained for two sets of saturated hydrocarbons. The reactivity of alkanes and cycloalkanes increases with increasing chain or side-chain length. Cycloalkanes are desirable components of advanced jet fuels, in terms of having higher thermal stability and density than n-alkanes of the same carbon number. The cis-isomer is usually more reactive than the trans-isomer, except for cis-1,3-dimethylcyclohexane. which is more stable than its trans-isomer. The presence of a branch or branches appears to decrease the decomposition rate compared to n-alkanes