What are glycol ethers?

Glycol ethers are a group of organic solvents consisting of a glycol or polyethylene glycol unit and an ether group. They combine the good solvent properties of alcohols and ethers and are used in a wide range of applications – from paints and coatings to cleaning agents, printing inks and chemical processes. Some glycol ethers are soluble in water, others are only soluble in organic solvents.

Formation

Glycol ethers are produced industrially by the reaction of ethylene oxide or propylene oxide with alcohols in the presence of acid or base catalysts. The variation of alcohols and the number of glycol units enables a wide range of physical and chemical properties.

Recognition

Glycol ethers are usually colorless, moderately volatile liquids with a mild, often slightly ethereal odor. Many are completely miscible with water and have good solubility for polar and non-polar substances. The viscosity and volatility depend on the size of the molecule and the structure.

Limit values

The occupational exposure limits vary depending on the compound. For ethylene glycol monobutyl ether, the OEL in the EU is 20 ppm (98 mg/m³), for propylene glycol monomethyl ether 50 ppm (188 mg/m³). Some glycol ethers are classified as toxic to reproduction, which is why special protective measures are required when using them.

Hazards

Some glycol ethers can be absorbed through the skin and respiratory tract and can be harmful to health. Possible effects include irritation of the eyes and respiratory tract, headaches, dizziness and, in the case of certain compounds, impairment of fertility or embryonic developmental disorders. Many glycol ethers are biodegradable in the environment, but can harm aquatic organisms in high concentrations.