Understanding Oil: Physical, Chemical Properties and Types

Physical Properties of Oil

Color: Varies from yellow to reddish-brown. The color darkens with increasing specific gravity, which increases with the percentage of asphalt.

Odor: Varies depending on the amount of light hydrocarbons and impurities. Examples include a pleasant smell of petrol to an unpleasant odor similar to combustion.

Specific Weight: Oil is lighter than water. Its weight is influenced by factors such as the percentage of asphalt.

Viscosity: Depending on the specific gravity and chemical composition, oil can be either very fluid or viscous.

Solubility: Insoluble in water; due to its lighter weight, it remains on the surface. It is soluble in benzene, ether, chloroform, and other organic solvents.

Chemical Properties of Oil

Crude oil is a dark, viscous liquid. In its natural state, it is a mixture of several hundred hydrocarbons.

Hydrocarbons: These are organic compounds consisting only of carbon and hydrogen atoms.

Oil is less dense than water and insoluble in it (density ranges from 0.75 to 0.95).

Types of Oil

The presence of various amounts of chemical components (organic and inorganic) determines the particular characteristics of the oil, such as color, density, and viscosity. These characteristics allow us to classify oil in different ways.

The types of oil may be determined differently according to the criteria considered dominant. The most common classification is:

By Chemical Composition

This type of classification is strictly dependent on the presence of certain chemical components in the oil, as well as the union of these more complex elements. Its importance lies in the special features that each of these elements adds to the oil. Thus, we can classify oil as:

• Paraffinic: The main component is the chemical compound called paraffin. These oils are very smooth and light-colored. They provide a higher amount of naphtha (used for paint thinner, dry cleaning products, or gasoline) and lubricants compared to other types of oil in the refining process.
• Naphthenic: The main components are naphthenes and aromatic hydrocarbons. These oils are very viscous and dark in color. They generate a large amount of waste after the refining process.
• Mixed: This type contains both paraffinic and naphthenic compounds.