Heat-release behavior of fuel combustion additives

The purpose of this study was to evaluate the relationship between solution -phase thermal stabilities of selected fuel additives and their effectivene ss as combustion improvers. The additives selected for this study were 2-et hylhexyl nitrate, isopropyl nitrate, tetraethylene glycol dinitrate, di(ter t-butyl) peroxide, and methylcyclopentadienyl manganese tricarbonyl. Decomp osition studies were carried out at various temperatures on the neat additi ves as well as the additives dissolved in various solvents and fuels. Diffe rential scanning calorimetry was used to survey thermal stabilities; high-p ressure differential scanning calorimetry was used to determine the effects of pressure on the decomposition exotherms of the additives. Critical temp eratures were calculated by the Frank-Kamenetskii equation for each additiv e. Neither the temperature of maximum exotherm nor the heat released by add itive decomposition correlated well with the effectiveness of a given addit ive as a cetane improver.