Liquid Paraffin (White Mineral Oil)
Liquid paraffin, also known by other names such as white mineral oil, white oil, or paraffin oil, is derived from the distillation of crude oil. In fact, it is considered a byproduct obtained from crude oil. This substance is colorless, transparent, and odorless, and is used for various purposes.
Liquid paraffin and mineral oil can essentially be considered the same chemical substance, as they are very similar and differ only slightly in their properties. To purify liquid paraffin from aromatic compounds, an extraction process is used, often involving ethylene glycol as the solvent. This purification serves two main purposes:
• ncreased purity: High purity is crucial for use in pharmaceuticals, lubricants, and food industries.
• Prevention of oxidation
This material is made up of alkane derivatives with a high boiling point, including heavy alkanes and their derivatives. It is insoluble in water and has low reactivity due to its saturated hydrocarbon structure.
Applications of Liquid Paraffin
Liquid paraffin is used in a wide range of industries, including pharmaceutical, cosmetic and personal care, and petrochemical industries for the production of polymers such as high-impact polystyrene. Notably, this substance is generally available in two types:
• High boiling point
• Low boiling point
The high boiling point type is known as kerosene, which is used in applications ranging from candle and polish manufacturing to cosmetic products. Major applications include:
• Fuel for oil lamps, with higher concentrations of high-boiling-point alkanes (not suitable for medical use)
• Pharmaceutical uses, such as in the production of penicillin, eczema treatments, and as a laxative
• In creams, ointments, and skin softeners
• As an industrial solvent and lubricant
• In the textile industry, for lubricating sewing machine parts
• In papermaking, due to its water-repellent properties
• In the rubber industry, as a filler.
Use of Liquid Paraffin in Polymer Manufacturing
This oil is widely used in polymer production industries as a lubricant, and in the rubber industry as a filler. Adding liquid paraffin to rubber increases the firmness and hardness of the rubber texture, enhancing its durability, especially when rubber is molded using a press.
If the paraffin content in rubber increases from 1% to 2%, a permanent thin layer forms on the rubber surface. Studies show that this thin film helps prevent oxidation due to light exposure. For producing rubber with low surface friction, the concentration may be increased to 3–5%. It is also added to prevent fading or discoloration of rubber. In rubber nets, 1–2% paraffin is used to reduce stiffness and toughness. In the aerospace industry, paraffin oil facilitates easy molding and provides uniform surface resistance in rubber products.
Paraffin oil is also used as a raw material in the chemical industry for synthesizing substances such as wax esters and chlorinated paraffins. Uses of chlorinated paraffins include:
• Alkylation of benzene and other aromatic derivatives
• Additives for lubricants
• Intermediates in lubricant synthesis
• Production of insecticides and pesticides
• Manufacturing of plastic products like PVC
• Polyester additives to enhance flame resistance
• Additives for paints
• Softening agents in textile dyes and rubber
• Food-grade packaging materials
Chlorinated paraffins also play a role in the production of natural rubber and elastomers, strengthening the bonds between nitrile groups and neoprene.
Other Applications: Corrosion Inhibition
Liquid paraffin is also used in the synthesis of metal corrosion inhibitors. By combining it with polyanilines, a corrosion inhibitor is created that can form a monolayer film on metal equipment, improving performance. The role of paraffin oil in this process is to dissolve or evenly disperse the active compounds, forming a single-phase mixture. Typically, the paraffin oil used has:
• A concentration of 40–50% in the total mixture
• A density of 0.8–0.9 g/cm³
• A kinematic viscosity of about 40 mm²/s
Safety and Storage
Despite its wide range of applications, liquid paraffin can be harmful to human health, especially the high boiling point type, if it comes into frequent contact with the skin, respiratory system, or digestive tract. Highly purified paraffin generally does not have harmful effects, but impure types are considered carcinogenic. Therefore, proper safety measures are essential.
Storage should be in a dry, cool, well-ventilated place, away from incompatible substances. Due to its high flammability, it must be kept away from heat sources and direct sunlight.
