What molecule am I?
March of this year was 鈥淪olvent Month鈥� 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 r in 27 US states.
- Significant amounts of the solvent 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鈥擧ighly flammable liquid and vapor |  |
| GHS classification: serious eye damage/eye irritation, category 2A | |
| H319鈥擟auses serious eye irritation |  |
| GHS classification: specific target organ toxicity, single exposure, respiratory tract irritation, category 3 | |
| H335鈥擬ay cause respiratory irritation | |
| GHS classification: carcenogenicity, category 2 | |
| H351鈥擲uspected of causing cancer |  |
*Globally Harmonized System of Classification and Labeling of Chemicals.聽
MOTW update: November 18, 2019
Former Molecules of the Week 1,4-dioxane, hexabromocyclododecane, 1-bromopropane, N-methyl-2-pyrrolidone, and dichloromethane, among several other chemicals, are at the center of a controversy about how the . The problems are the lack of expertise in some of the committees and a shortage of adquate data to evaluate the chemicals. Industrial and environmental stakeholders are critical of the latest risk assessments.
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 潞C |
| Boiling point | 101.1 潞C |
| Water solubility | Miscible |
MOTW update:聽
February 10, 2025
1,4-Dioxane1聽is a common solvent that has come under scrutiny as a suspected carcinogen and a drinking water and groundwater contaminant. In recent years, dioxane has been of concern as a contaminant in ingredients used to formulate household products. A 2022 New York State law restricts the concentration of dioxane in cleaning and personal care products to 1 ppm and in cosmetics to 10 ppm. But some jurisdictions believe that regulations should be even tighter; in one case, regulators are proposing a in consumer products rather than the product as a whole.
1. CAS Reg. No. 123-91-1.
MOTW update:
January 18, 2021
Dioxane is a valuable solvent that has many industrial and laboratory uses. In 2019, it came under regulatory pressure because it is a possible carcinogen and has been found in drinking water and groundwater in several states. On December 31, 2020, the US Environmental Protection Agency released a of dioxane that pleased neither environmentalists, state attorneys general, nor the chemical industry. Among the report鈥檚 other shortcomings, EPA ignored drinking-water exposure; environmentalists and regulators say that this is dioxane鈥檚 greatest threat to the general population.
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