August 05, 2019
I’m a useful solvent, but I have a dark side.
What molecule am I?

March of this year was “Solvent Month” for Molecule of the Week. Another commonly used solvent is 1,4-dioxane, usually referred to simply as dioxane.1 It is a cyclic diether that has an odor similar to that of its more volatile cousin, diethyl ether.

In 1928, IG Farbenindustrie (precursor to BASF) patented a manufacturing process for dioxane in which diethylene glycol is heated with a small amount of sulfuric acid. Today, it is still produced in much the same way. It is used industrially as a solvent for cellulose esters and ethers, adhesives, inks, and many other materials.

Dioxane, however, is coming under regulatory pressure because of health and environmental concerns:

  • A suspected carcinogen, dioxane has been found to contaminate drinking water in 27 US states.
  • Significant amounts of the solvent have been found in groundwater in New York State, prompting a bill in the legislature that would ban it in cleaning and personal care products.
  • The US Occupational Safety and Health Administration is considering regulating worker exposure to dioxane.

1. Structural isomers 1,2- and 1,3-dioxane have been prepared, but they are not commercial products.

1,4-Dioxane hazard information

GHS classification*: flammable liquids, category 2
H225—Highly flammable liquid and vapor Chemical Safety Warning
GHS classification: serious eye damage/eye irritation, category 2A
H319—Causes serious eye irritation Chemical Safety Warning
GHS classification: specific target organ toxicity, single exposure, respiratory tract irritation, category 3
H335—May cause respiratory irritation Chemical Safety Warning
GHS classification: carcenogenicity, category 2
H351—Suspected of causing cancer Chemical Safety Warning

*Globally Harmonized System of Classification and Labeling of Chemicals. Explanation of pictograms.

1,4-Dioxane fast facts

CAS Reg. No. 123-91-1
Empirical formula C4H8O2
Molar mass 88.11 g/mol
Appearance Colorless liquid
Melting point 11.8 ºC
Boiling point 101.1 ºC
Water solubility Miscible
Chemical Abstract Service - a division of ACS

Learn more about this molecule from CAS, the most authoritative and comprehensive source for chemical information.

Molecule of the Week needs your suggestions!

If your favorite molecule is not in our archive, please send an email to motw@acs.org. The molecule can be notable for its current or historical importance or for any quirky reason. Thank you!

Stay Ahead of the Chemistry Curve

Learn how ACS can help you stay ahead in the world of chemistry.