Glycol ethers


Glycol ethers are a class of chemical compounds consisting of alkyl ethers that are based on glycols such as ethylene glycol or propylene glycol. They are commonly used as solvents in paints and cleaners. They have good solvent properties while having higher boiling points than the lower-molecular-weight ethers and alcohols.

History

The name Cellosolve was registered in 1924 as a United States trademark by Carbide & Carbon Chemicals Corporation for "Solvents for Gums, Resins, Cellulose Esters, and the Like". Ethyl Cellosolve, or simply Cellosolve, consists mainly of ethylene glycol monoethyl ether and was introduced as a lower-cost solvent alternative to ethyl lactate. Butyl Cellosolve was introduced in 1928, and Methyl Cellosolve in 1929.

Types

Glycol ethers are designated E-series or P-series for those 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- 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.

Health impacts

Most glycol ethers are water-soluble, biodegradable and only a few are considered toxic.
In the early 1990s, studies found a higher than expected rates of human reproductive health issues in both males and females, such as elevated risk of miscarriages among women who worked in semiconductor plants as well as male gonadal changes such as testicular atrophy and sperm morphology changes, which was traced back to glycol ethers; in particular: ethylene glycol ethers used in the photoresist substances that coat semiconductors.
One study suggests that occupational exposure to glycol ethers is related to lowering the motility of the sperm and sperm count, a finding disputed by the chemical industry.

Subclasses

Monoalkyl ethers