This paper attempts to expand mechanistic understanding of the fundamental chemistry involved in jet fuel thermal oxidative deposit formation. The proposed mechanisms are a synthesis of ideas and results from the fuel community at large; a few new experiments are also reported. In addition, it is suggested that the available literature is consistent with similar chemistry for deposit formation for both storage and thermal oxidative degradation for middle distillates in general.

It is anticipated that future jet fuels will be required to handle a thermal stress of approximately 900 °F (480 °C). Such an environment presents many challenges in providing fuels with the necessary thermal oxidative and pyrolytic stability. We report single-tube flow reactor data which suggests that addition of 100 ppm of dicyclohexylphenyl phosphine (DCP) to an air saturated JP-8, followed by stressing up to ∼675 °C, provides significant improvement in both thermal oxidative and pyrolytic stability. In addition, we present our current mechanistic understanding of how DCP might stabilize jet fuels under these extreme conditions. Finally, this work required us to reformulate the electron-transfer-initiated oxygenation (ETIO) mechanism proposed to explain the reaction of DCP with molecular oxygen.

A model study is described that tests the feasibility of using dicyclohexylphenylphosphine (DCP) as an additive to provide oxidative stability for future jet fuels. In addition, the mechanism of autoxidation of DCP in dodecane is examined.