 On the other hand, isobutanol has a lower melting point than n-butanol and favorable RON of 113 and MON of 94, and is thus much better suited to high fraction gasoline blends, blends with n-butanol, or as a standalone fuel.A fuel with a higher octane rating is less prone to knocking (extremely rapid and spontaneous combustion by compression) and the control system of any modern car engine can take advantage of this by adjusting the ignition timing.This will improve energy efficiency, leading to a better fuel economy than the comparisons of energy content different fuels indicate.