Epichlorohydrin can be hydrolyzed to glycerol. The epichlorohydrin process is the most important: it involves the chlorination of propylene to give allyl chloride, which is oxidized with hypochlorite to dichlorohydrin, which reacts with a strong base to give epichlorohydrin.
Synthetic glycerol Īlthough usually not cost-effective, glycerol can be produced by various routes from propene. High purity glycerol (greater than 99.5%) is obtained by multi-step distillation a vacuum chamber is necessary due to its high boiling point (290 ☌). Ĭrude glycerol from the hydrolysis of triglycerides can be purified by treatment with activated carbon to remove organic impurities, alkali to remove unreacted glycerol esters, and ion exchange to remove salts. Some glycerol is burned for energy, but its heat value is low. It can be purified, but the process is expensive. Glycerol from triglycerides is produced on a large scale, but the crude product is of variable quality, with a low selling price of as low as US$0.02–0.05 per kilogram in 2011. It was projected in 2006 that by 2020, production would be six times more than demand, creating an excess of glycerol as a byproduct of biofuel production. The EU directive 2003/30/EC set a requirement that 5.75% of petroleum fuels were to be replaced with biofuel sources across all member states by 2010. Approximately 950,000 tons per year are produced in the United States and Europe 350,000 tons of glycerol were produced per year in the U.S. Typical plant sources include soybeans or palm. Triglycerides can be saponified with sodium hydroxide to give glycerol and fatty sodium salt or soap. The hydrolysis, saponification, or transesterification of these triglycerides produces glycerol as well as the fatty acid derivative: Glycerol is generally obtained from plant and animal sources where it occurs in triglycerides, esters of glycerol with long-chain carboxylic acids. Thus, in substituted derivatives, the stereospecific numbering labels the molecule with a sn- prefix before the stem name of the molecule. Structure Īlthough achiral, glycerol is prochiral with respect to reactions of one of the two primary alcohols. Because of its three hydroxyl groups, glycerol is miscible with water and is hygroscopic in nature. It is also widely used as a sweetener in the food industry and as a humectant in pharmaceutical formulations. It can be used as an effective marker to measure liver disease. Conversely, it is also used as a bacterial culture medium. Because it has antimicrobial and antiviral properties, it is widely used in wound and burn treatments approved by the U.S. The glycerol backbone is found in lipids known as glycerides. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. Glycerol ( / ˈ ɡ l ɪ s ə r ɒ l/), also called glycerine in British English and glycerin in American English, is a simple triol compound.
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