N-heptane high purity grade 99% differs from regular heptane in terms of composition free of other isomers . It is a straight-chain alkane having seven carbons and appears as a colorless liquid with a petroleum-like smell. It is the main constituent of gasoline and used as a standard for the octane rating of fuels. Our n-heptane is certified as the american chemical society acs reagent due to its high level of purity. The reagent grade is generally equivalent to the acs grade and is acceptable for use in analytical applications and research laboratories.