1,4-Dioxane

Description

1,4-dioxane is a clear liquid with ether-like odour. It is highly flammable and forms explosive peroxides in storage (rate of formation increased by heating, evaporation, or exposure to light). 1,4-Dioxane is incompatible with oxidising agents, oxygen, halogens, reducing agents, and moisture. Industrial applications of 1,4-dioxane are extensive, for instance, as solvent for cellulose acetate, ethyl cellulose, benzyl cellulose, resins, oils, waxes, and 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 and 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 and breathing of contaminated workplace air and drinking polluted water. Industrial uses of 1,4-dioxane are very many. For instance, it is used as solvent for celluloses, resins, lacquers, synthetic rubbers, adhesives, sealants, fats, oils, dyes, and protective coatings; as a stabiliser for chlorinated solvents and printing inks; and as a wetting and dispersing agent in textile processing agrochemicals and pharmaceuticals, in different processing of solvent-extraction processes, and in the preparation and manufacture of detergents.

Description

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

Description

Dioxane is a common aprotic solvent in organic chemistry. It is an ethereal solvent which is miscible with water. Dioxane can sometimes be a useful alternative to THF when a higher boiling point is desired. Commercially available 4M HCl in dioxane is one of the most frequently encountered applications of dioxane as a solvent. The use of 4M HCl in dioxane is common for boc deprotections.

Chemical properties

1,4-Dioxane is a colorless, stable liquid with a faint, pleasant odor. Although it has been known as far back as 1863, it was not until 1929 that is became commercially available. It is chemically a di-ether obtained by the loss of water from two molecules of ethylene glycol. It is completely soluble in water, as well as most organic solvents. It is freely soluble in mineral, vegetable, blown and heat-bodied oils, and oil soluble dyes. Most waxes are more readily soluble in dioxane when heated and examples of these are beeswax, carnauba, montan, paraffin, gilsonite, and Japan wax.

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 ppb_v) and 6.5 mg/m³ (1.8 ppm_v), respectively (Hellman and Small, 1974).

The Uses of 1,4-Dioxane

1,4-Dioxane, the six-member cyclic diether, is used as an aluminum inhibitor in chlorinated solvents like 1,1,1-trichloroethane and as a solvent for certain resins and polymers.

The Uses of 1,4-Dioxane

The Iodo compound (308 mg, 0.513 mmol), the boronic ester (194 mg, 0.641 mmol), K3PO4 (327 mg, 1.539 mmol), XPhos (14.67 mg, 0.031 mmol), and Pd2(dba)3 (14.09 mg, 0.015 mmol) were combined in a microwave vial. The vial was purged with argon, after which time was added dioxane (3 mL) and H2O (0.5 mL) The reaction was irradiated in a microwave reactor at 120 C for 10 min. Additional boronic ester (50 mg) was added and the mixture was irradiated at 120 C for another 10 min. The mixture was then treated with aq 1N NaOH and extracted with EtOAc (50 mL). The org layer was dried (MgSO4), concentrated, and purified by flash chromatography (20% MeOH/DCM) to provide the product as a dark yellow solid. [177 mg, 53%]

The Uses of 1,4-Dioxane

Suitable for HPLC, spectrophotometry, environmental testing

The Uses of 1,4-Dioxane

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 Compounds.

The Uses of 1,4-Dioxane

1,4-Dioxane is used as a solvent for celluloseesters, oils, waxes, resins, and numerousorganic and inorganic substances. It is alsoused in coatings and as a stabilizer in chlorinatedsolvents.

What are the applications of Application

1,4-Dioxane is a compound also known as Diethylene oxide

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.

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.

Air & Water Reactions

Highly flammable. When exposed to air 1,4-Dioxane undergoes autooxidation with formation of peroxides. In the distillation process peroxides will concentrate causing violent explosion. Water soluble.

Reactivity Profile

1,4-Dioxane is a flammable liquid; when exposed to air 1,4-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 1,4-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].

Health Hazard

The toxicity of 1,4-dioxane is low in testanimals by all routes of exposure. However,in humans the toxicity of this compoundis severe. The target organs are theliver, kidneys, lungs, skin, and eyes. Exposureto its vapors as well as the absorptionthrough the skin or ingestion can cause poisoning,the symptoms of which include drowsiness,headache, respiratory distress, nausea,and vomiting. It causes depression of centralnervous system. There are reports of humandeaths from subacute and chronic exposures todioxane vapors at concentration levels rangingbetween 500 and 1000 ppm. Serious healthhazards may arise from its injurious effects onthe liver, kidneys, and brain. Rabbits died ofkidney injury resulting from repeated inhalationof 1,4-dioxane vapors for 30 days (Smyth1956). It is an irritant to the eyes, nose, skin,and lungs. In humans, a 1-minute exposure to5000-ppm vapors can cause lacrimation.
LC50 value, inhalation (rats): 13,000 ppm/2 h
LD50 value, oral (mice): 5700 mg/kg
1,4-Dioxane is an animal carcinogen oflow potential. Ingestion of high concentrationsof this compound at a level of7000–18,000 ppm in drinking water for14–23 months caused nasal and liver tumorsin rats (ACGIH 1986). Guinea pigs developedlung tumors.

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.

Safety Profile

Confirmed carcinogen with experimental carcinogenic, neoplastigenic, tumorigenic, and teratogenicdata. Poison by intraperitoneal route. Moderately toxic by ingestion and inhalation. Mildly toxic by skin contact. Human systemic effects by inhalation: lachrymation, conjunctiva irritation, convulsions, hgh blood pressure, unspecified respiratory and gastrointestinal system effects. Mutation data reported. An eye and slun irritant. The irritant effects probably provide sufficient warning, in acute exposures, to enable a worker to leave exposure before being seriously affected. Repeated exposure to low concentrations has resulted in human fatahties, the organs chefly affected being the liver and kidneys. A very dangerous fire and explosion hazard when exposed to heat or flame; can react vigorously with oxidizing materials. Violent reaction with (H2 + Raney Ni), AgClO4. Can form dangerous peroxides when exposed to air. Potentially explosive reaction with nitric acid + perchloric acid, Raney nickel catalyst (above 210°C). Forms explosive mixtures with decaborane (impactsensitive), triethynylaluminum (sensitive to heating or drying). Violent reaction with sulfur trioxide. Incompatible with sulfur trioxide. To fight fire, use alcohol foam, CO2, dry chemical. When heated to decomposition it emits acrid smoke and irritating fumes. See also GLYCOL ETHERS.

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.

Precautions

Workers Should be careful during handling of 1,4-Dioxane and avoid open flames, sparks and smoking. Workers should wear proper protectives since 1,4-Dioxane in known as hazardous, cause damage to eyes, respiratory tract, liver and kidney.