It is understood that: Glycerin (also known as glycerin) is a colorless, odorless, sweet-tasting organic substance with a clear and viscous liquid appearance. It is miscible with water, alcohols, amines and phenols in any proportion, and the aqueous solution is neutral. Glycerin is a polyol moisturizer. The hydroxyl groups in the molecular structure can form hydrogen bonds with water molecules, which plays a good role in absorbing and locking water. Glycerin has a wide range of uses. Currently, it has more than 1,700 uses. It is used in both food and industry. The industrial production methods of glycerol can be divided into two categories: methods using natural oils as raw materials, and the resulting glycerin is commonly known as natural glycerin; and synthetic methods using propylene as raw materials, and the resulting glycerol is commonly known as synthetic glycerol.
About the production of natural glycerin:
Before 1984, glycerin was all recovered from the by-products of animal and vegetable fat soap making. Until now, natural oils and fats are still the main raw materials for the production of glycerol. About 42% of the natural glycerin in the base comes from soap by-products, and 58% comes from fatty acid production. Saponification reaction of fats and oils in soap making industry. The saponification reaction product is divided into two layers: the upper layer mainly contains sodium salts of fatty acids (soap) and a small amount of glycerol, and the lower layer is waste alkali liquid, which is a dilute glycerol solution containing salts and sodium hydroxide, generally containing 9-16% of glycerol and inorganic salts. 8-20%. Grease reaction. Glycerin water (also called sweet water) obtained by hydrolysis of oils and fats has a higher glycerin content than soapmaking waste liquid, about 14-20%, and inorganic salts of 0-0.2%. In recent years, continuous high-pressure hydrolysis has been widely used. The reaction does not use a catalyst. The sweet water obtained generally does not contain inorganic acid, and the purification method is simpler than that of spent alkali. Whether it is soap-making waste liquid or glycerol water obtained by hydrolysis of oil, the amount of glycerol is not high, and they all contain various impurities. The production process of natural glycerin includes purification and concentration to obtain crude glycerin, as well as distillation, decolorization, and Deodorization refining process. This process is described in detail in some books and periodicals.
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