Glycol ethers

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",;^[1] 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.

Recent study suggests that occupational exposure to glycol ethers is related to low motile sperm count,^[2] a finding disputed by the chemical industry.^[3]

Glycol ether solvents

• Ethylene glycol monomethyl ether (2-methoxyethanol, CH₃OCH₂CH₂OH)
• Ethylene glycol monoethyl ether (2-ethoxyethanol, CH₃CH₂OCH₂CH₂OH)
• Ethylene glycol monopropyl ether (2-propoxyethanol, CH₃CH₂CH₂OCH₂CH₂OH)
• Ethylene glycol monoisopropyl ether (2-isopropoxyethanol, (CH₃)₂CHOCH₂CH₂OH)
• Ethylene glycol monobutyl ether (2-butoxyethanol, CH₃CH₂CH₂CH₂OCH₂CH₂OH), a widely used solvent in paintings and surface coatings, cleaning products and inks
• Ethylene glycol monophenyl ether (2-phenoxyethanol, C₆H₅OCH₂CH₂OH)
• Ethylene glycol monobenzyl ether (2-benzyloxyethanol, C₆H₅CH₂OCH₂CH₂OH)
• Diethylene glycol monomethyl ether (2-(2-methoxyethoxy)ethanol, methyl carbitol, CH₃OCH₂CH₂OCH₂CH₂OH)
• Diethylene glycol monoethyl ether (2-(2-ethoxyethoxy)ethanol, carbitol cellosolve, CH₃CH₂OCH₂CH₂OCH₂CH₂OH)
• Diethylene glycol mono-n-butyl ether (2-(2-butoxyethoxy)ethanol, butyl carbitol, CH₃CH₂CH₂CH₂OCH₂CH₂OCH₂CH₂OH)

Dialkyl ethers

• Ethylene glycol dimethyl ether (dimethoxyethane, CH₃OCH₂CH₂OCH₃), a higher boiling alternative to diethyl ether and THF, also used as a solvent for polysaccharides, a reagent in organometallic chemistry and in some electrolytes of lithium batteries
• Ethylene glycol diethyl ether (diethoxyethane, CH₃CH₂OCH₂CH₂OCH₂CH₃)
• Ethylene glycol dibutyl ether (dibutoxyethane, CH₃CH₂CH₂CH₂OCH₂CH₂OCH₂CH₂CH₂CH₃)

Esters

• Ethylene glycol methyl ether acetate (2-methoxyethyl acetate, CH₃OCH₂CH₂OCOCH₃)
• Ethylene glycol monoethyl ether acetate (2-ethoxyethyl acetate, CH₃CH₂OCH₂CH₂OCOCH₃)
• Ethylene glycol monobutyl ether acetate (2-butoxyethyl acetate, CH₃CH₂CH₂CH₂OCH₂CH₂OCOCH₃)
• Propylene glycol methyl ether acetate (1-methoxy-2-propanol acetate)

References

1. Union Carbide also registered "Cellosolve" as a trademark for "ETHYL SILICATES FOR USE AS BINDERS IN INVESTMENT CASTINGS AND IN ZINC-RICH PRIMERS" (Reg. Number 1019768, September 9, 1975), but let it expire
2. Nicola Cherry, Harry Moore, Roseanne McNamee, Allan Pacey, Gary Burgess, Julie-Ann Clyma, Martin Dippnall, Helen Baillie and Andrew Povey (2008). "Occupation and male infertility: glycol ethers and other exposures". Occup. Environ. Med. 65 (10): 708–714. doi:10.1136/oem.2007.035824. PMID 18417551.
3. Peter J Boogaard, Gerard M H Swaen (2008). "Letter to the editor on a recent publication titled "Occupation and male infertility: glycol ethers". Occup. Environ. Med.