Diesel has a low octane number. Though octane isn't used for diesel fuel, it can be determined and is around 15-25.

Diesel engines avoid pre-ignition knocking by compressing only air. There is no compression of air/fuel mix. The fuel is injected into the hot, compressed air at the top of the compression stroke (at something like 3000+ PSI, IIRC).

The fuel does not have to be particularly volatile because of the high compression and the injector's atomization.

In theory, diesel engines can run on "anything". Diesel engines have been run on crude oil taken directly from the ground (of good purity), and on vegetable oil.