Cetane is the 16-carbon hydrocarbon (and therefore has 32 plus 2, or 34, hydrogens). Interestingly, C16H34 (chemical formula for cetane) is used as the reference hydrocarbon to assign a quality measurement for diesel fuels. Diesel fuels are rated by their "cetane number," just as regular gas is rated by its "octane number." (Octane is the 8-carbon hydrocarbon, C8H18.)
Why do I find this interesting? First off, it's exactly double the number of carbons as octane. That makes me think that what's going on in the engine with the fuel is a series of snapping these chains in half over and over again until you get single-carbon bits that come out as carbon monoxide, carbon dioxide or perhaps unburned methane. 16-carbon chains blast into 8's, and they blast into 4's, which break into 2's, which break into singles.
Second, I read in wikipedia that diesel fuel is thicker than regular gas, which makes sense if the chains it contains are longer.
Interesting bit 3: the chemically scientific name for this is not cetane, but hexadecane, because "hexadec~" means 16. But why should that be???
THAT, is the most interesting bit of of all. It's called cetane because of the word "cetus," which means whales or dolphins, because it was found to be the main component of whale oil! So, it got its name BEFORE all the chemically scientific hydrocarbon names came out: methane, ethane, propane, butane, pentane, hexane, etc. (1, 2, 3, 4, 5, 6, etc.) I had wondered how it got such a simple name, how it rose above the rest so to speak.
And why did I get interested in this? I'm thinking of buying a car, and one I saw that I liked is a diesel, and so I wikipedia'd that because I was curious, and wikipedia told me diesel is rated by "cetane number," and that is one "~ane" I had not come across before, which puzzled me. God I love science.
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