Propylene Glycol is a propanediol that exists as a clear, colorless and hygroscopic liquid and consists of propane where the hydrogens at positions 1 and 2 are substituted by hydroxyl groups. Propylene glycol, with a formula C3H8O2, is used as an organic solvent and diluent in pharmaceuticals and many other industrial applications.
It is manufactured by the hydration of propylene oxide. However in large doses it can be toxic, especially if given over a short period of time. Intravenous lorazepam contains the largest amount of propylene glycol of commonly used drugs.
An ingredient found in many personal-care products like shampoo, hair conditioner, and styling product, propylene glycol is widely used because of its relatively low cost and versatile nature.
Its inclusion in a formula can fulfill a variety of purposes, which makes it a popular choice by the cosmetics chemist. However, some manufacturers have recently made the decision to no longer include propylene glycol in their products.
Propylene glycol is added as a food ingredient to common products, such as frostings, candies, and even baked goods. It is used as a component in natural flavorings to help distribute the flavoring evenly throughout the product.
Applications of Propylene Glycol
PG uses as an ingredient in engine coolants, deicing fluids and antifreeze. It has replaced ethylene glycol as the base fluid for aircraft deicing formulations and a coolant in the food industry. Propylene glycol is preferred over ethylene glycol due to its much lower toxicity.
Propylene glycol is used as a solvent and extractant. Solvent applications include alkyd resins, printing inks and coatings.
Propylene glycol finds broad use as a humectant in the pharmaceutical, cosmetic, animal food and tobacco industries. Cosmetics include personal care products such as antiperspirants and deodorants. In these applications, PG keeps the moisture content of the materials in a narrow range despite fluctuations in environmental humidity.
Industrial grade PG is used in the production of polyglycols for hydraulic and brake fluids; some examples of industrial usage of PG:
1.Adhesives, Sealants and Coatings
2.Alkyd Resins for Paint and Coatings
5.Unsaturated Polyester Resins
7.Aircraft Deicing Fluids
8.Heat Transfer / Thermal Fluids (with a suitable inhibitor)
9.Hydraulic and Brake Fluids
10.Coolants and Antifreeze
Dust suppression, Dyes and Inks, Lubricants, Natural Gas Dehydrations, Plasticizers, Surfactants, Waxes