It has an initial boiling point (IBP) of about 35 ☌ and a final boiling point (FBP) of about 200 ☌, and it contains paraffins, naphthenes (cyclic paraffins) and aromatic hydrocarbons ranging from those containing 4 carbon atoms to those containing about 10 or 11 carbon atoms. The naphtha is a mixture of many different hydrocarbon compounds. The overhead liquid distillate from that unit is called virgin or straight-run naphtha and that distillate is the largest source of naphtha in most petroleum refineries. The first unit operation (after being desalinated) in a petroleum refinery is the crude oil distillation unit. Naphthas may also be produced from other material such as coal tar, shale deposits, tar sands, and the destructive distillation of wood. Naphtha is a general term as each refinery produces its own naphthas with their own unique initial and final boiling points and other physical and compositional characteristics.
There are also hundreds of petroleum refineries worldwide and each of them is designed to process either a specific crude oil or specific types of crude oils. There are hundreds of different petroleum crude oil sources worldwide and each crude oil has its own unique composition or assay. It is most usually desulfurized and then catalytically reformed, which rearranges or restructures the hydrocarbon molecules in the naphtha as well as breaking some of the molecules into smaller molecules to produce a high- octane component of gasoline (or petrol). Petroleum naphtha is an intermediate hydrocarbon liquid stream derived from the refining of crude oil with CAS-no 6. For the hydrocarbon mixture derived from a number of natural sources, see naphtha. This article is about naphthas derived from crude oil.