Chemical Properties
1,4-dioxane is a clear liquid with an ether-like odor. It is highly flammable
and forms explosive peroxides in storage (rate of formation is increased by heating,
evaporation, or exposure to light). 1,4-Dioxane is incompatible with oxidizing agents,
oxygen, halogens, reducing agents, and moisture. 1,4-Dioxane is used as a solvent for
cellulose acetate, ethyl cellulose, benzyl cellulose, resins, oils, waxes, some dyes, as a
solvent for paper, cotton, and textile processing, and for various organic and inorganic
compounds and products. It is also used in automotive coolant liquid, in shampoos
and other cosmetics as a degreasing agent, and as a component of paint and varnish.
Human exposures to 1,4-dioxane have been traced to multiple occupations, breathing
of contaminated workplace air, and drinking polluted water. There are many industrial
uses of 1,4-dioxane, i.e., as a solvent for celluloses, resins, lacquers, synthetic rubbers,
adhesives, sealants, fats, oils, dyes, and protective coatings; as a stabilizer for chlorinated
solvents, printing inks; as a wetting and dispersing agent in textile processing,
agrochemicals, and pharmaceuticals, and in the preparation and manufacture of
detergents.
General Description
A clear colorless liquid with a faint ethereal odor. Flash point 55°F. Slightly denser than water and soluble in water. Vapors heavier than air. Susceptible to autooxidation to form peroxides.
Reactivity Profile
DIOXANE is a flammable liquid; when exposed to air DIOXANE undergoes autooxidation with formation of peroxides. In the distillation process peroxides will concentrate causing violent explosion. The addition complex with sulfur trioxide (1:1) sometimes decomposes violently on storing at room temperature [Sisler, H. H. et al., Inorg. Synth., 1947, 2, p. 174]. Evaporation of boron trifluoride in aqueous dioxane with nitric acid led to an explosion upon addition of perchloric acid [MCA Guide, 1972, p. 312]. Explosive reaction with Raney nickel catalyst above 210° C {Mozingo R., Org. Synth., 1955, Coll. Vol. 3, p. 182].
Air & Water Reactions
Highly flammable. When exposed to air DIOXANE(123-91-1) undergoes autooxidation with formation of peroxides. In the distillation process peroxides will concentrate causing violent explosion. Water soluble.
Health Hazard
Laboratory studies in experimental animals indicate that repeated exposures to large
amounts of 1,4-dioxane in drinking water, in air, or on the skin cause convulsions, collapse,
and damage to the liver and kidneys in animals. On inhalation of 1,4-dioxane, occupational
workers suffered from severe poisoning. The symptoms of poisoning included
coughing, irritation of eyes, drowsiness, vertigo, headache, anorexia, stomach pains, nausea,
vomiting, irritation of the upper respiratory passages, coma, and death. 1,4-Dioxane
also caused hepatic and renal lesions, and demyelination and edema of the brain among
workers. (See the literature for more information.)
Health Hazard
No significant irritation from brief exposure of skin; prolonged or repeated exposure may cause a rash or burn and absorption of toxic amounts leading to serious injury of liver and kidney. Chemical has poor warning properties; illness may be delayed. Moderately irritating to eyes; overexposure may cause corneal injury.
Physical properties
Clear, colorless, very flammable, volatile liquid with a faint pleasant, ether-like odor.
Experimentally determined detection and recognition odor threshold concentrations were 2.9
mg/m3 (800 ppbv) and 6.5 mg/m3 (1.8 ppmv), respectively (Hellman and Small, 1974).
Definition
ChEBI: A dioxane with oxygen atoms at positions 1 and 4.
Definition
dioxan: A colourless toxic liquid,C4H8O2; r.d. 1.03; m.p. 11°C; b.p.101.5°C. The molecule has a sixmemberedring containing fourCH2groups and two oxygen atoms at oppositecorners. It can be made fromethane-1,2-diol and is used as a solvent.
Flammability and Explosibility
Dioxane is a highly flammable liquid (NFPA rating = 3). Its vapor is heavier than air and may travel a considerable distance to a source of ignition and flash back. Dioxane vapor forms explosive mixtures with air at concentrations of 2 to 22% (by volume). Fires involving dioxane should be extinguished with carbon dioxide or dry powder extinguishers.
Dioxane can form shock- and heat-sensitive peroxides that may explode on concentration by distillation or evaporation. Samples of this substance should always be tested for the presence of peroxides before distilling or allowing to evaporate. Dioxane should never be distilled to dryness.
Potential Exposure
Tumorigen,Mutagen; Reproductive Effector; Human Data; PrimaryIrritant. Dioxane is used as a stabilizer in chlorinated solvents, and as a solvent for cellulose acetate; other primaryuses include as a solvent for dyes, fats, greases, lacquers,mineral oil; paints, polyvinyl polymers; resins, varnishes,and waxes. It finds particular usage in paint and varnishstrippers; as a wetting agent and dispersing agent in textileprocessing; dye baths; stain and printing compositions; andin the preparation of histological slides.
First aid
If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Seek medical attention immediately. Ifthis chemical has been inhaled, remove from exposure,begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medical attention. Give large quantities of water and inducevomiting. Do not make an unconscious person vomit.
Carcinogenicity
1,4-Dioxane is reasonably anticipated to be a human carcinogen basedon sufficient evidence of carcinogenicity from studies in experimental animals.
Source
Improper disposal of products listed below may result in 1,4-dioxane leaching into
groundwater.
Environmental Fate
Biological. Heukelekian and Rand (1955) reported a 10-d BOD value of 0.00 g/g which is 0.0%
of the ThOD value of 1.89 g/g.
Photolytic. Irradiation of pure 1,4-dioxane through quartz using a 450-W medium-pressure
mercury lamp gave meso and racemic forms of 1-hydroxyethyldioxane, a pair of diastereomeric
dioxane dimers (Mazzocchi and Bowen, 1975), dioxanone, dioxanol, hydroxymethyldioxane, and
hydroxyethylidenedioxane (Houser and Sibbio, 1977). When 1,4-dioxane is subjected to a
megawatt ruby laser, 4% was decomposed yielding ethylene, carbon monoxide, hydrogen, and a
trace of formaldehyde (Watson and Parrish, 1971).
Chemical/Physical. Anticipated products from the reaction of 1,4-dioxane with ozone or OH
radicals in the atmosphere are glyoxylic acid, oxygenated formates, and OHCOCH2CH2OCHO
(Cupitt, 1980). Storage of 1,4-dioxane in the presence of air resulted in the formation of 1,2-
ethanediol monoformate and 1,2-ethane diformate (Jewett and Lawless, 1980). Stefan and Bolton (1998) studied the degradation of 1,4-dioxane in dilute aqueous solution by OH radicals.
Degradation follows pseudo-first-order kinetics at a rate of 8.7 x 10-3/sec. Within 5 min of direct
photolysis of hydrogen peroxide to generate OH radicals, almost 90% of the 1,4-dioxane reacted.
Four primary intermediate formed were 1,2-ethanediol monoformate, 1,2-ethanediol diformate,
formic acid, and methoxyacetic acid. These compounds were attacked by OH radicals yielding
glycolic, glyoxylic, and acetic acids which led to oxalic acid as the last intermediate. Malonic acid
was also identified as a minor intermediate. Twelve minutes into the reaction, the pH decreased
rapidly to 3.25 from 5.0, then less rapidly to 3.25 after 23 min. After 1 h, the pH rose to 4.2 min.
The decrease of pH during the initial stages of reaction is consistent with the formation of organic
acids. Oxidation of organic acid by OH radicals led to an increase of pH. The investigators
reported that the lower pH at the end of the experiment was due to carbonic acid formed during the
mineralization process.
storage
dioxane should be used only in areas free of ignition sources, and quantities greater than 1 liter should be stored in tightly sealed metal containers in areas separate from oxidizers. Containers of dioxane should be dated when opened and tested periodically for the presence of peroxides.
Shipping
This compound requires a shipping label of“FLAMMABLE LIQUID.” It falls in Hazard Class 3 andPacking Group II.
Purification Methods
It is prepared commercially either by dehydration of ethylene glycol with H2SO4 and heating ethylene oxide or bis(.-chloroethyl)ether with NaOH. The usual impurities are acetaldehyde, ethylene acetal, acetic acid, water and peroxides. Peroxides can be removed (and the aldehyde content decreased) by percolation through a column of activated alumina (80g per 100-200mL solvent), by refluxing with NaBH4 or anhydrous stannous chloride and distilling, or by acidification with conc HCl, shaking with ferrous sulfate and leaving in contact with it for 24hours before filtering and purifying further. Hess and Frahm [Chem Ber 71 2627 1938] refluxed 2L of dioxane with 27mL conc HCl and 200mL water for 12hours with slow passage of nitrogen to remove acetaldehyde. After cooling the solution, KOH pellets were added slowly and with shaking until no more would dissolve and a second layer had separated. The dioxane was decanted, treated with fresh KOH pellets to remove any aqueous phase, then transferred to a clean flask where it was refluxed for 6-12hours with sodium, then distilled from it. Alternatively, Kraus and Vingee [J Am Chem Soc 56 511 1934] heated it on a steam bath with solid KOH until fresh addition of KOH gave no more resin (due to acetaldehyde). After filtering through paper, the dioxane was refluxed over sodium until the surface of the metal was not further discoloured during several hours. It was then distilled from sodium. The acetal (b 82.5o) is removed during fractional distillation. Traces of *benzene, if present, can be removed as the *benzene/MeOH azeotrope by distillation in the presence of MeOH. Distillation from LiAlH4 removes aldehydes, peroxides and water. Dioxane can be dried using Linde type 4X molecular sieves. Other purification procedures include distillation from excess C2H5MgBr, refluxing with PbO2 to remove peroxides, fractional crystallisation by partial freezing and the addition of KI to dioxane acidified with aqueous HCl. Dioxane should be stored out of contact with air, preferably under N2. A detailed purification procedure is as follows: Dioxane is stood over ferrous sulfate for at least 2 days, under nitrogen. Then water (100mL) and conc HCl (14mL)/ litre of dioxane are added (giving a pale yellow colour). After refluxing for 8-12hours with vigorous N2 bubbling, pellets of KOH are added to the warm solution to form two layers and to discharge the colour. The solution is cooled rapidly with more KOH pellets being added (magnetic stirring) until no more dissolved in the cooled solution. After 4-12hours, if the lower phase is not black, the upper phase is decanted rapidly into a clean flask containing sodium, and refluxed over sodium (until freshly added sodium remained bright) for 1hour. The middle fraction is collected (and checked for minimum absorbency below 250nm). The distillate is fractionally frozen three times by cooling in a refrigerator, with occasional shaking or stirring. This material is stored in a refrigerator. Before use it is thawed, refluxed over sodium for 48hours, and distilled into a container. All joints are clad with Teflon tape. Coetzee and Chang [Pure Appl Chem 57 633 1985] dried the solvent by passing it slowly through a column (20g/L) of 3A molecular sieves activated by heating at 250o for 24hours. Impurities (including peroxides) are removed by passing the effluent slowly through a column packed with type NaX zeolite (pellets ground to 0.1mm size) activated by heating at 400o for 24hours or chromatographic grade basic Al2O3 activated by heating at 250o for 24hours. After removal of peroxides the effluent is refluxed for several hours over sodium wire, excluding moisture, distilled under nitrogen or argon and stored in the dark. One of the best tests of purity of dioxane is the formation of the purple disodium benzophenone complex during reflux and its persistence on cooling. (Benzophenone is better than fluorenone for this purpose and for the storing of the solvent.) [Carter et al. Trans Faraday Soc 56 343 1960, Beilstein 19 V 16.] TOXIC. Rapid purification: Check for peroxides (see Chapter 1 and Chapter 2 for test under ethers). Pre-dry with CaCl2 or better over Na wire. Then reflux the pre-dried solvent over Na (1% w/v) and benzophenone (0.2% w/v) under an inert atmosphere until the blue colour of the benzophenone ketyl radical anion persists. Distil, and store it over 4A molecular sieves in the dark.
Toxicity evaluation
Eye and respiratory irritation occurs from direct contact of
1,4-dioxane with mucous membranes. Pharmacokinetic and
toxicological data indicate that liver and kidney toxicity
induced by 1,4-dioxane occurs only after doses large enough to
saturate processes for detoxification and elimination.
1,4-Dioxane is one of many carcinogens that have not been
demonstrated to react significantly with DNA. Its cancer mode
of action is not sufficiently well understood to permit assignment
to a specific class of epigenetic agents. However, the data
suggest a tumor promotion mechanism associated with tissue
injury and subsequent regeneration.
Incompatibilities
Dioxane can form potentially explosive peroxides upon long exposure to air. Dioxane may react violently with Raney nickel catalyst, nitric and perchloric acids, sulfur trioxide, and strong oxidizing reagents.
Waste Disposal
Excess dioxane and waste material containing this substance should be placed in an appropriate container, clearly labeled, and handled according to your institution's waste disposal guidelines.
