Glycol ethers are a group of solvents based on alkyl ethers of ethylene glycol or propylene glycol commonly used in paints and cleaners. These solvents typically have a higher boiling point, together with the favorable solvent properties of lower-molecular weight ethers and alcohols. The word "Cellosolve" was registered in 1924 as a United States trademark by Carbide & Carbon Chemicals Corp. (later named Union Carbide Corp.) for "Solvents for Gums, Resins, Cellulose Esters, and the Like". The first one was ethyl cellosolve (ethylene glycol monoethyl ether), with the name now generic for glycol ethers.
Glycol ethers are either "e-series" or "p-series" glycol ethers, depending on whether they are made from ethylene oxide or propylene oxide, respectively. Typically, e-series glycol ethers are found in pharmaceuticals, sunscreens, cosmetics, inks, dyes and water-based paints, while p-series glycol ethers are used in degreasers, cleaners, aerosol paints and adhesives. Both E-series glycol ethers and P-series glycol ethers can be used as intermediates that undergo further chemical reactions, producing glycol diethers and glycol ether acetates. P-series glycol ethers are marketed as having lower toxicity than the E-series. Most glycol ethers are water-soluble, biodegradable and only a few are considered toxic.
One study suggests that occupational exposure to glycol ethers is related to low motile sperm count, a finding disputed by the chemical industry.