Glycerin, also spelled glycerine, is a basic ingredient in most soap. In fact, it is a by-product of soap manufacture as it occurs due to the reaction of strong alkali with an animal fat. This process is known as saponification and it is this process that brings out soap or detergent. While most manufacturers separate glycerin from the mixture, others incorporate the compound for its natural benefits.
Lots of soap-makers recommend glycerin as a basic ingredient because it has the ability to draw in moisture preventing drying of the skin. The compound is a natural moisturizer. In fact, it is a humectant – a substance that attracts water. Thus, soap containing the hygroscopic compound is known to have skin conditioning and moisturizing effect.
Glycerin is a viscous liquid that is at the same time sweet and colorless. It solidifies to a paste-like substance and has a high boiling point. During the soap-making process, some manufacturers remove the compound from the soap mixture and incorporate it into other products like lotion and creams. However, when it is added to a bar of soap it results to a nearly transparent product with moisturizing properties.
The compound is known to be a good solvent and this is one of its most remarkable properties. In some instances, it is better as a solvent than water or alcohol. This property makes it highly miscible in both alcohol and water. However, it never dissolves in oils. In its pure form the compound is called glycerol which suggests it belongs to a classification of organic compounds called alcohol.
It is extremely hygroscopic, which means that it readily absorbs moisture from the air. For instance, leaving a flask of pure glycerol open allows attraction of water that it soon loses the purity.
It was in 1889 when the compound was first obtained from animal fat through candle making. During which time the only way to derive the compound is through this process. Also, in that time animal fat was the only raw material for making candles. During the World War II, it has become a major component of dynamites and heavy demand for the substance was not sufficed by soap making industry. Thus there was an abrupt production of synthetic forms of the compound.
The substance has a chemical formula C3H8O3 which is also occurs as a liquid by-product during the production of biodiesel in a process called transesterification. This syrupy liquid occurs in nature. Found in cells of plants and animals (including humans), it is a part of the large bio-molecules of many lipids. In biologic processes the compound occurs as a result of the fermentation of carbohydrates. In organic chemistry it is produced by propylene synthesis.
Glycerin is an ingredient in several health-care products and toiletries. It is found in food products, as well as pharmaceutical and cosmetic items. It is found in moisturizing lotions and creams because of its hydrophilic and hygroscopic properties, which allow the substance to retain moisture. There is a debate whether it is the hygroscopic properties of the compound that makes it good for the skin, or it may be possible that the chemical has other unexplored and unidentified properties aside from the one already mentioned. The moisture-drawing property makes it an excellent emollient when added in soaps and moisturizing creams. An emollient is a substance that smoothens and softens skin. Another reason personal care products utilizes the substance is because of its skin lubricating advantage, not to mention it serves as a thickening or emulsifying agent in cosmetic products.
Home-made soaps or the hand-made varieties naturally contain glycerol, which commercial soap-makers remove. The separated liquid is used in massage oils, lip balms, skin softeners and moisturizers, perfumes and essential oils, and pharmaceutical preparations.