Paraffin is a general term used to describe a class of hydrocarbons that exist either as a waxy solid or a thin, colorless oil. Paraffin is fundamentally derived from crude oil during the refining process, making it a petroleum product. Chemically, paraffin is categorized as a mixture of saturated hydrocarbons, specifically the alkane family of molecules. These compounds consist only of carbon and hydrogen atoms connected by single bonds, which grants them high chemical stability.
Paraffin’s Place in the Petroleum Family
Petroleum, or crude oil, is a complex organic mixture made primarily of various hydrocarbon molecules, and paraffins are a major constituent of this raw material. In chemistry, the word “paraffin” is synonymous with “alkane,” referring to the straight-chain saturated hydrocarbons that are separated out during refining. These molecules follow a general chemical structure where the physical state of the final product is determined by the length of the carbon chain.
Paraffin products are broadly separated into two main categories based on their molecular size. Paraffin wax, the solid form, is composed of heavier, straight-chain molecules that typically contain between 20 and 40 carbon atoms. Conversely, liquid paraffin, often referred to as mineral oil, consists of lighter molecules with a shorter chain length. The saturated nature of the molecules, meaning they have no double or triple bonds, contributes to their low reactivity, which makes them desirable for a wide range of industrial and consumer applications.
From Crude Oil to Usable Wax
Paraffin production begins with the fractional distillation of crude oil in a refinery, separating components based on their boiling points. The paraffin components are found within the heavier fractions, specifically the lubricating oil fraction, which is also known as waxy oil. This heavy residue is the precursor to the final paraffin products.
The waxy oil fraction is then processed further to extract the crude wax mixture, known as slack wax, which still contains a significant amount of residual oil. To purify this mixture, a process called solvent dewaxing is employed, where the slack wax is heated and mixed with solvents like ketones or toluene. The mixture is then carefully cooled, which causes the wax to crystallize out of the solution while the oil remains liquid. Specialized filters are used to separate the solid wax crystals from the oily liquid, yielding a purer wax product.
Finally, the separated crude wax undergoes a series of stringent purification steps to create commercial-grade paraffin wax or mineral oil. These steps often involve hydrofinishing, which treats the wax with hydrogen under high pressure and temperature to remove remaining impurities and enhance its color and odor stability.
Common Everyday Applications
The inert and hydrophobic nature of refined paraffin products makes them highly versatile for many everyday uses across different industries. Solid paraffin wax is widely used in the production of candles, where its clean-burning properties and ability to hold fragrance and color are valued. It also serves as an effective moisture barrier in the food industry, where it is applied as a coating for certain cheeses and candies, and as a sealant for food packaging materials. Industrial applications include its use as a lubricant to reduce friction and as an electrical insulator to protect components from moisture.
Liquid paraffin, or mineral oil, is similarly utilized for its stable and non-reactive characteristics. In the cosmetic and pharmaceutical industries, highly refined liquid paraffin is a common ingredient in many lotions, creams, and makeup removers, functioning as an occlusive agent that forms a protective barrier on the skin to lock in moisture. Medically, it is used as a gentle laxative, as it passes through the digestive tract without being absorbed, softening stool and aiding passage.