Petroleum diesel, is the most common type of diesel fuel. It is produced from the fractional distillation of crude oil between 200 °C (392 °F) and 350 °C (662 °F) at atmospheric pressure, resulting in a mixture of carbon chains that typically contain between 8 and 21 carbon atoms per molecule.
The important properties which are used to characterize diesel fuel include cetane number (or cetane index), fuel volatility, density, viscosity, cold behavior, and sulfur content. .
Standard diesel fuel (sometimes called diesel oil) comes in two grades: Diesel #1 (or 1-D) and Diesel #2 (or 2-D). The higher the cetane number, the more volatile the fuel.