n-Heptane is a straight-chain alkane. It is a colorless, volatile, flammable liquid with weak odor. n-Heptane is almost immiscible in water, but soluble in organic solvents. It is the zero point of the octane rating scale, as it burns explosively, causing engine knocking, as opposed to branched-chain octane isomers, which burn more slowly and give better performance.
n-Heptane contains in crude oil and can be isolated by ceolite absorption;
as a zero point in definition of octane number of petrols;
as an inert non-polar solvent;