Heptane is a chain of 7 carbons, with n-heptane being the straight chain of 7 carbons (the "n" in n-heptane stands for "normal" which means a straight carbon chain.) Heptane is available as pure n-heptane but also as mixed isomers (branched chains of 7 carbons).
N-Heptane is used in laboratories as a non-polar solvent. Branched/mixed isomers of heptane is used in paints and coatings. Even though heptane is a hydrocarbon, it is not added to gasoline mixtures because it burns explosively, causing engine knocking.
Up Stream Materials/Building Blocks:
Heptane (n-heptane), Straight carbon Chain
Coproducts: isomers/branched heptane:
2,2,3-Trimethylbutane,(aka pentamethylethane and triptane)
Down Stream Materials Consuming Heptane:
Camp stove fuel