Insight into the mechanisms of middle distillate fuel oxidative degradation. Part 2: On the relationship between jet fuel thermal oxidative deposit, soluble macromolecular oxidatively reactive species, and smoke point

We present data that suggest that jet fuel smoke point and the formation of thermal oxidative deposit are linked by formation of a common intermediate, high molecular weight soluble macromolecular oxidatively reactive species (SMORS). Hardy and Wechter (Energy Fuels 1994, 8, 782-787) have previously observed that with diesel fuels containing unhydrotreated light cycle oil (LCO), the highest molecular weight fraction of SMORS can be conveniently quantified as an extraction-induced precipitate (EIP). These authors have also shown that for fresh diesel fuel, oxidatively stressed fuel EIP mass correlates well with results of accelerated storage stability determined by ASTM 5304. Consistent with this, data are presented that suggest EIP mass, from jet fuels oxidatively stressed in tubing bombs, correlates with mean thermal oxidative deposition in a flowing reactor. In addition, data are presented that suggest that for a polar compound doped oxidatively stressed jet fuel, EIP mass correlates with the total concentration of polar compounds doped into the fuel. Thus, for the first time the concentration of select polar aromatics has been directly linked with the formation of a deposit precursor (Energy Fuels 1994, 8, 782-787) and smoke point.