PETROLEUM
color and viscosity.
The alkanes, also known as paraffins, are saturated hydrocarbons with straight or
branched chains which contain only carbon and hydrogen and have the general formula
CnH2n+2. They generally have from 5 to 40 carbon atoms per molecule, although trace
amounts of shorter or longer molecules may be present in the mixture.
The alkanes from pentane (C5H12) to octane (C8H18) are refined into petrol, the ones
from nonane (C9H20) to hexadecane (C16H34) into diesel fuel, kerosene and jet fuel.
Alkanes with more than 16 carbon atoms can be refined into fuel oil and lubricating oil.
At the heavier end of the range, paraffin wax is an alkane with approximately 25 carbon
atoms, while asphalt has 35 and up, although these are usually cracked by modern
refineries into more valuable products. The shortest molecules, those with four or fewer
carbon atoms, are in a gaseous state at room temperature. They are the petroleum
gases
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