A little more than two hundred years ago a chemist named Carl W. Scheele from Sweden heated olive oil and an oxide of lead called litharge. He was amazed to discover a thick liquid that came out of the mixture. He did not know what it was at first. And never did he think it would become one of the most important industrial and commercial chemicals in the world today.
He named it glycerol, from the Greek word glykys, meaning sweet. Indeed he discovered a sweet-tasting substance. During the next studies made about the compound, it was identified to be a major component of fats and oils - that it is in chemical combination with fatty acid molecules to form glycerides. In the coming centuries since its inception, it became widely used in industrial manufacturing. This compound is also known as glycerin or glycerine.
In its pure form C3H8O3 or glycerol has no odor and color but has a sweet taste. It is a thick, syrupy liquid and is quite miscible in alcohol and water. In fact, there are instances that the chemical is used as a solvent. It does not dissolve in hydrocarbons though. At very low temperatures it solidifies into crystals that melt at 18 degrees Celsius. The liquid form boils at 290 degrees Celsius at standard conditions.
During the World War II heavy demands for the compound rose because it is an ingredient to synthesize nitroglycerine - an ingredient of explosives and heart-disease medications as well. However, it is not an explosive by itself. During this time there was huge reliance on soap making as a source of the substance since this process yields glycerin as a byproduct.
A related and similar method of extracting the chemical is through hydrolysis of fats or oils. Currently, however, another way of producing the compound is through preparation from a hydrocarbon source called propylene. Depending on its purity, the compound may be used in a vast number of ways. The crude, unrefined glycerin is an ingredient of dynamites, for instance. The pure, refined form is the one which is used in food and medicines.
In nearly all industries, the substance has a role to fit in. Its unique properties make it a valuable chemical used in pharmaceutical preparations and cosmetics. It is in fact, an ingredient of a huge collection of products from skin care to medicines. It is a hygroscopic and hydrophilic chemical, which means it absorbs water. Thus, when found in lotions, creams and soaps, it enhances the moisturizing and skin-softening feature of these products.
This is the reason why commercial soap manufacturers remove the glycerin that naturally forms in the soap mixture. They use the chemical in more valuable and profitable products as lotions, creams and other cosmetics. The same feature explains why hand-made or home-made soaps, whose glycerin component remains in the mixture, have more skin-moisturizing effects.
In pharmaceutical preparations, it acts as a humectant, preventing creams and ointments from drying out. It is about 60% as sweet as table sugar, that is why it acts as a sweetener or a sugar substitute. It is also a good emulsifying agent that it has the ability to keep insoluble particles of a mixture in uniform dispersion, preventing precipitation or settling of insoluble particles. This is particularly an advantage in medications that must be kept in colloidal suspension.
In baked food, like cakes, the moisture-retaining property of the substance is an advantage because it keeps them soft and moist. It also moistens and softens some candies. It is an excellent solvent for many products like tinctures, extracts, food coloring agents, and food flavorings. Tobacco tastes sweet and remains damp because of its presence on the leaves, and this prevents the leaves from crumbling when rolled and folded. Paints, coatings, glues, adhesives, cellophanes, and meat casings contain glycerin.