Glycols, Ethylene Glycol and Oligomers

AbstractGlycols are diols, compounds containing two hydroxyl groups attached to separate carbon atoms. In an aliphatic chain, ethylene glycol, is the simplest glycol. Diethylene, triethylene, and tetraethylene glycols are oligomers of ethylene glycol. Polyglycols are higher molecular weight adducts of ethylene oxide and are distinguished by intervening ether linkages in the hydrocarbon chain. These polyglycols are commercially important; their properties are significantly affected by molecular weight. They are water soluble, hygroscopic, and undergo reactions common to the lower weight glycols.The uses for ethylene glycol are numerous. Some of the applications are polyester resins for fiber, PET containers, and film applications; all‐weather automotive antifreeze and coolants, defrosting and deicing aircraft; heat‐transfer solutions for coolants for gas compressors, heating, ventilating, and air‐conditioning systems; water‐based formulations such as adhesives, latex paints, and asphalt emulsions; manufacture of capacitors; and unsaturated polyester resins. The oligomers also have excellent water solubility but are less hygroscopic and have somewhat different solvent properties. The largest commercial use of ethylene glycol is its reaction with dicarboxylic acids to form linear polyesters.The first commercial application of the Lefort direct ethylene oxidation to ethylene oxide followed by hydrolysis of ethylene oxide remains the main commercial source of ethylene glycol production.In addition to oligomers ethylene glycol derivative classes include monoethers, diethers, esters, acetals, and ketals as well as numerous other organic and organometallic molecules.