Triethylene glycol, also known as triethylene glycol diethylene glycol, 2,2-ethylenedioxyethylenediethanol, is an organic alcohol with the molecular formula C6H14O4 and a molecular weight of approximately 150.17. It is typically a colorless, odorless, viscous liquid with a relative density of 1.12, a boiling point of 278.3℃, a freezing point of -7.2℃, a flash point of 176.7℃, and an autoignition temperature of 371.1℃. It is readily soluble in water and miscible with most fatty alcohols, ketones, esters, and low-molecular-weight halogenated hydrocarbons. Triethylene glycol is a weak acid and can react with active metals; it can undergo nucleophilic substitution reactions with hydrohalic acids; it can undergo intermolecular dehydration reactions with oxygen-containing inorganic acids; and it can undergo dehydration reactions upon heating under the catalysis of protic or Lewis acids. Due to the presence of ether bonds, it is not easily oxidized or dehydrogenated.
Triethylene glycol is mainly derived from the byproduct of ethylene glycol production by hydration of ethylene oxide, and can also be produced by reacting ethylene oxide with ethylene glycol in the presence of an alkaline catalyst. Triethylene glycol can be used as an aromatic hydrocarbon extractant, a dehydrating and drying agent for natural gas and associated gas from oil fields, and a wetting agent for tobacco and inks; it is used in the production of polyethers and polyurethane foams; it is used to synthesize triethylene glycol esters, used as plasticizers and lubricants for PVC; it is used to synthesize triethylene glycol alkyl ethers, used as high-boiling-point solvents; it is used to synthesize triethylene glycol dichloride, used as a solvent for oils, fats, waxes, etc., and as an intermediate raw material for pharmaceutical bactericides, chemicals, and surfactants; it is used to synthesize crown ethers, used as catalysts in organic synthesis, for the chelation and separation of heavy metals, and for ion-selective electrodes; it is used to synthesize tetraethylene glycol or higher glycols, used as aromatic hydrocarbon extractants and in the production of fine chemical products; it can also be used as a disinfectant in air conditioning systems and a softener for rayon.
