Title: Dioxane
CAS Registry Number: 123-91-1
Additional Names: 1,4-Diethylene dioxide
Molecular Formula: C4H8O2
Molecular Weight: 88.11
Percent Composition: C 54.53%, H 9.15%, O 36.32%
Literature References: Prepd by distilling ethylene glycol with dil H2SO4. Monograph: W. Stumpf, Chemie und Anwendungen des 1,4-Dioxans (Verlag Chemie, 1956). Toxicity data: E. P. Laug et al., J. Ind. Hyg. Toxicol. 21, 173 (1939). Carcinogenicity studies: M. F. Argus et al., J. Natl. Cancer Inst. 35, 949 (1965); R. J. Kociba et al., Toxicol. Appl. Pharmacol. 30, 275 (1974).
Properties: Flammable liq; faint pleasant odor. Vapor harmful. d420 1.0329. mp 11.80°. bp760 101.1°; bp400 81.8°; bp200 62.3°; bp100 45.1°; bp60 33.8°; bp40 25.2°; bp20 12°. Cryoscopic constant 4.83. Trouton constant 21.90. Heat of combustion: 581 kcal/mol. Heat of fusion: 2.98 kcal/mol. Specific heat at 20° = 0.0370 kcal/mol/°C. Viscosity (25°): 0.0120 P. Crit temp 312°. Crit press 50.7 atm. Flash pt 5-18°C. nD20 1.4175. Dipole moment: zero. Azeotropic mixture with water: 81.6% dioxane, bp 87.8°. Azeotropic mixture with ethanol: 9.3% dioxane, bp 78.1°. Sol in water and the usual organic solvents. Tends to form explosive peroxides, especially when anhydr. LD50 in mice, rats (ml/kg): 5.7, 5.2 orally (Laug).
Melting point: mp 11.80°
Boiling point: bp760 101.1°; bp400 81.8°; bp200 62.3°; bp100 45.1°; bp60 33.8°; bp40 25.2°; bp20 12°; bp 87.8°; bp 78.1°
Flash point: Flash pt 5-18°C
Index of refraction: nD20 1.4175
Density: d420 1.0329
Toxicity data: LD50 in mice, rats (ml/kg): 5.7, 5.2 orally (Laug)
CAUTION: Potential symptoms of overexposure are drowsiness, headache; nausea, vomiting; irritation of eyes, skin, nose and throat; liver damage; kidney failure. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 120. This substance is reasonably anticipated to be a human carcinogen: Report on Carcinogens, Eleventh Edition (PB2005-104914, 2004) p III-110.
Use: Stabilizer in chlorinated solvents. Solvent for cellulose acetate, ethyl cellulose, benzyl cellulose, resins, oils, waxes, oil and spirit-sol dyes, and many other organic as well as some inorganic compds.
Dioxaphetyl Butyrate Dioxethedrine Dioxybenzone Dioxypyramidon Diperodon Hydrochloride

Chemical structure of dioxane 1,4-dioxane
CAS number 123-91-1 YesY
ChemSpider 29015 YesY
EC number 204-661-8
DrugBank DB03316
KEGG C14440 YesY
ChEBI CHEBI:47032 YesY
Jmol-3D images Image 1
Molecular formula C4H8O2
Molar mass 88.11 g mol−1
Density 1.033 g/mL
Melting point 11.8 °C; 53.2 °F; 284.9 K
Boiling point 101.1 °C; 214.0 °F; 374.2 K
Solubility in water Miscible
Std molar
entropy So298
196.6 J·K−1·mol−1
Std enthalpy of
formation ΔfHo298
-354 kJ/mol
Std enthalpy of
combustion ΔcHo298
-2363 kJ/mol
EU classification Flammable (F)
Carc. Cat. 3
Irritant (Xn)
R-phrases R11, R19, R36/37,
R40, R66
S-phrases (S2), S9, S16,
S36/37, S46
NFPA 704
NFPA 704.svg
Flash point 12 °C; 54 °F; 285 K
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Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

1,4-Dioxane, often called dioxane because the 1,2 and 1,3 isomers of dioxane are rare, is a heterocyclic organic compound. It is a colorless liquid with a faint sweet odor similar to that of diethyl ether. It is classified as an ether. Dioxane is used mainly as a stabilizer for the solvent trichloroethane. It is an occasionally used solvent for a variety of practical applications as well as in the laboratory.