One of my coworkers says his chemistry teacher told them (a long time ago) that kerosene has a higher octane value than gasoline. My understanding was always that aviation gasoline has octane value above 120, but it is really gasoline, while kerosene is more like diesel fuel. What is the truth?
Octane rating is a measure of how well a fuel resists detonation, which is the premature explosion of fuel in an engine cylinder before the spark is applied. This is relevant for spark ignition engines which use gasoline type fuels like avgas.
Kerosene has a very low octane rating, somewhere around 15, and isn't a good fuel for spark ignition engines as it would detonate on compression. This is why kerosene and diesel are used in diesel cycle engines which rely on the spontaneous detonation of fuel under pressure. Kerosene is not typically used in internal combustion engines, however in aviation there are turbo-diesel piston engines which run on Jet-A1.