Distillation is the process of heating a liquid until it boils, capturing and cooling the resultant hot vapors, and collecting the condensed vapors. Distillation is a powerful tool, both for the identification and the purification of organic compounds. The boiling point of a compound—determined by distillation—is well-defined and thus is one of the physical properties of a compound by which it is identified. Distillation is used to purify a compound by separating it from a non-volatile or less-volatile material. When different compounds in a mixture have different boiling points, they separate into individual components when the mixture is carefully distilled. The first step in the refining process. During distillation, crude oil is heated in the base of a distillation tower. As the temperature increases, the crude’s various compounds vaporize in succession at their various boiling points, then rise to prescribed levels within the tower according to their densities, condense in distillation trays, and are drawn off individually for further refining