What is the primary method used to separate the compounds found in crude oil?

The primary method used to separate the compounds found in crude oil is fractional distillation. This technique takes advantage of the different boiling points of the various hydrocarbons present in crude oil. As crude oil is heated, components with lower boiling points vaporize first and can be collected, while those with higher boiling points remain in the liquid phase. This process allows for the effective separation of the mixtures into different fractions, such as gasoline, kerosene, diesel, and lubricating oils, each of which has distinct properties and uses.

Filtration is not suitable for separating the components of crude oil due to the liquid nature of the mixture; it is more appropriate for separating solids from liquids. Recrystallization is typically used for purifying solid compounds, not for separating mixtures of liquids like those found in crude oil. Evaporation could separate some components based on volatility but lacks the precision and efficiency needed for the complex mixture in crude oil, making fractional distillation the preferred method.