Glycolic acid, also known as hydroxyacetic acid, is a type of alpha hydroxyl acid. It is a versatile acid used in products from cosmetics to industrial cleaning solutions. The simplest of the alpha hydroxyl acids, the small organic molecules of glycolic acid contain both acidic and alcoholic properties. Pure glycerine is actually glycerol, an alcohol. Glycerine refers to the impure, commercial version of glycerol.
Glycolic acid is found naturally in grapes, beets, other fruits and sugarcane and is nonflammable. Glycerine is found naturally in fat and is extracted from the fats involved in soap manufacturing.
Odour and Toxicity
Glycolic acid has negligible odour and low toxicity. Pure glyercin is odourless and nontoxic with a sweet taste, but crude glycerine, the byproduct of biodiesel production is neither odourless nor nontoxic.
Glycerol is water soluble, leaving little residue when rinsed off. It dilutes easily and is a flexible liquid in manufacturing due to its low salt content.
Glycerine dissolves in water or alcohol, but it will not dissolve in oils. It is also a solvent because certain substances dissolve more quickly in glycerine than in alcohol or water.
Industrial-grade glycolic acid is used in cleaning products for hard surfaces, metal, concrete, boilers, and dairy and food equipment. It is also used in textile dyeing, industrial chemical manufacturing, petroleum refining and printed circuit board manufacturing.
Years ago, the primary use of glycerine years was making dynamite. Glycerine has also been used to lubricate moulds, as an anti-freezing agent for hydraulic jacks, as an ingredient in printing inks and to preserve science specimens.
In recent years, skin care products containing alpha hydroxyl acids have increased in popularity. A cosmetic grade of glycolic acid is used for its ability to slough off dead skin cells and freshen the look of skin. Glycolic acid also reduces the amount of surface skin oil, which aids in the removal of blackheads and other skin impurities and may help stimulate collagen production within the dermis, the layer of the skin located below the epidermis.
Pure glycerine might cause blisters but diluted with water, glycerine acts as a skin softening agent. Glycerine can be used as a base for lotions and is used to make pure soaps --- soaps that melt quickly in water.
Medicinal and Food Uses
Glycerol is sometimes used as a laxative. Its high water content causes stool to soften. It can also be used as a ophthalmic agent to reduce eye pressure prior to eye surgery.
Glycerine is used in conserving preserved fruit and in candy and cake making. It may also be safely used in cough and acetaminophen syrups.