This article is from the Gasoline FAQ, by Bruce Hamilton with numerous contributions by others.
Propylene oxide ( CH3CH(O)CH2 = 1,2 epoxypropane ) has apparently been
used in racing fuels, and some racers erroneously claim that it behaves
like nitrous oxide. It is a fuel that has very desirable volatility,
flammability and autoignition properties. When used in engines tuned for
power ( typically slightly rich ), it will move the air-fuel ratio closer
to stoichiometric, and the high volatility, high autoignition temperature
( high octane ), and slightly faster flamespeed may improve engine
efficiency with hydrocarbon fuels, resulting in increased power without
major engine modifications. This power increase is, in part, due to the
increase in volumetric efficiency from the requirement for less oxygen
( air ) in the charge. PO is a suspected carcinogen, and so should be
handled with extreme care.
Relevant properties include [116]:
Avgas Propylene Oxide 100/130 115/145 Density (g/ml) 0.828 0.72 0.74 Boiling Point (C) 34 30-170 30-170 Stoichiometic Ratio (vol%) 4.97 2.4 2.2 Autoignition Temperature (C) 464 440 470 Lower Flammable Limit (vol%) 2.8 1.3 1.2 Upper Flammable Limit (vol%) 37 7.1 7.1 Minimum Ignition Energy (mJ) 0.14 0.2 0.2 Nett Heat of Combustion (MJ/kg) 31.2 43.5 44.0 Flame Temperature (C) 2087 2030 2030 Burning Velocity (m/s) 0.67 0.45 0.45
 
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