1,4-Dioxane (/daɪˈɒkseɪn/) is a heterocyclic organic compound, classified as an ether. It is a colorless liquid with a faint sweet odor similar to that of diethyl ether. The compound is often called simply dioxane because the other dioxane isomers (1,2- and 1,3-) are rarely encountered.
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| Names | |||
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| Preferred IUPAC name
1,4-Dioxane | |||
| Systematic IUPAC name
1,4-Dioxacyclohexane | |||
| Other names
[1,4]Dioxane
p-Dioxane [6]-crown-2 Diethylene dioxide Diethylene ether Dioxane solvent | |||
| Identifiers | |||
3D model (JSmol)
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| 102551 | |||
| ChEBI | |||
| ChEMBL | |||
| ChemSpider | |||
| DrugBank | |||
| ECHA InfoCard | 100.004.239 | ||
| EC Number |
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| KEGG | |||
PubChem CID
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| RTECS number |
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| UNII | |||
| UN number | 1165 | ||
CompTox Dashboard (EPA)
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| Properties | |||
| C4H8O2 | |||
| Molar mass | 88.106 g·mol−1 | ||
| Appearance | Colorless liquid[1] | ||
| Odor | Mild, diethyl ether-like[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) | ||
| Miscible | |||
| Vapor pressure | 29 mmHg (20 °C)[1] | ||
| −52.16·10−6 cm3/mol | |||
| Thermochemistry | |||
Std molar
entropy (S⦵298) |
196.6 J/K·mol | ||
Std enthalpy of
formation (ΔfH⦵298) |
−354 kJ/mol | ||
Std enthalpy of
combustion (ΔcH⦵298) |
−2363 kJ/mol | ||
| Hazards | |||
| Occupational safety and health (OHS/OSH): | |||
Main hazards
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Suspected human carcinogen[1] | ||
| GHS labelling: | |||
  
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| Danger | |||
| H225, H302, H305, H315, H319, H332, H336, H351, H370, H372, H373 | |||
| P201, P202, P210, P233, P240, P241, P242, P243, P260, P261, P264, P270, P271, P280, P281, P302 P352, P303 P361 P353, P304 P312, P304 P340, P305 P351 P338, P307 P311, P308 P313, P312, P314, P321, P332 P313, P337 P313, P362, P370 P378, P403 P233, P403 P235, P405, P501 | |||
| NFPA 704 (fire diamond) | |||
| Flash point | 12 °C (54 °F; 285 K) | ||
| 180 °C (356 °F; 453 K) | |||
| Explosive limits | 2.0–22%[1] | ||
| Lethal dose or concentration (LD, LC): | |||
LD50 (median dose)
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LC50 (median concentration)
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LCLo (lowest published)
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1000–3000 ppm (guinea pig, 3 hr) 12,022 ppm (cat, 7 hr) | ||
| NIOSH (US health exposure limits): | |||
PEL (Permissible)
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TWA 100 ppm (360 mg/m3) [skin][1] | ||
REL (Recommended)
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Ca C 1 ppm (3.6 mg/m3) [30-minute][1] | ||
IDLH (Immediate danger)
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Ca [500 ppm][1] | ||
| Related compounds | |||
Related compounds
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Oxane Trioxane Tetroxane Pentoxane | ||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Dioxane is used as a solvent for a variety of practical applications as well as in the laboratory, and also as a stabilizer for the transport of chlorinated hydrocarbons in aluminium containers.[3]
Synthesis
editDioxane is produced by the acid-catalysed dehydration of diethylene glycol, which in turn is obtained from the hydrolysis of ethylene oxide.
In 1985, the global production capacity for dioxane was between 11,000 and 14,000 tons.[4] In 1990, the total U.S. production volume of dioxane was between 5,250 and 9,150 tons.[5]
Structure
editThe dioxane molecule is centrosymmetric, meaning that it adopts a chair conformation, typical of relatives of cyclohexane. However, the molecule is conformationally flexible, and the boat conformation is easily adopted, e.g. in the chelation of metal cations. Dioxane resembles a smaller crown ether with only two ethyleneoxyl units.
Uses
editTrichloroethane transport
editIn the 1980s, most of the dioxane produced was used as a stabilizer for 1,1,1-trichloroethane for storage and transport in aluminium containers. Normally aluminium is protected by a passivating oxide layer, but when these layers are disturbed, the metallic aluminium reacts with trichloroethane to give aluminium trichloride, which in turn catalyses the dehydrohalogenation of the remaining trichloroethane to vinylidene chloride and hydrogen chloride. Dioxane "poisons" this catalysis reaction by forming an adduct with aluminium trichloride.[4]
As a solvent
edit
Dioxane is used in a variety of applications as a versatile aprotic solvent, e.g. for inks, adhesives, and cellulose esters. It is substituted for tetrahydrofuran (THF) in some processes, because of its lower toxicity and higher boiling point (101 °C, versus 66 °C for THF).[6]
While diethyl ether is rather insoluble in water, dioxane is miscible and in fact is hygroscopic. At standard pressure, the mixture of water and dioxane in the ratio 17.9:82.1 by mass is a positive azeotrope that boils at 87.6 °C.[7]
The oxygen atoms are weakly Lewis-basic. It forms adducts with a variety of Lewis acids. It is classified as a hard base and its base parameters in the ECW model are EB = 1.86 and CB = 1.29.
Dioxane produces coordination polymers by linking metal centers.[8] In this way, it is used to drive the Schlenk equilibrium, allowing the synthesis of dialkyl magnesium compounds.[4] Dimethylmagnesium is prepared in this manner:[9][10]
- 2 CH3MgBr (C2H4O)2 → MgBr2(C2H4O)2 (CH3)2Mg
Spectroscopy
editDioxane is used as an internal standard for nuclear magnetic resonance spectroscopy in deuterium oxide.[11]
Toxicology
editSafety
editDioxane has an LD50 of 5170 mg/kg in rats.[4] It is irritating to the eyes and respiratory tract. Exposure may cause damage to the central nervous system, liver and kidneys.[12] In a 1978 mortality study conducted on workers exposed to 1,4-dioxane, the observed number of deaths from cancer was not significantly different from the expected number.[13] Dioxane is classified by the National Toxicology Program as "reasonably anticipated to be a human carcinogen".[14] It is also classified by the IARC as a Group 2B carcinogen: possibly carcinogenic to humans because it is a known carcinogen in other animals.[15] The United States Environmental Protection Agency classifies dioxane as a probable human carcinogen (having observed an increased incidence of cancer in controlled animal studies, but not in epidemiological studies of workers using the compound), and a known irritant (with a no-observed-adverse-effects level of 400 milligrams per cubic meter) at concentrations significantly higher than those found in commercial products.[16] Animal studies in rats suggest that the greatest health risk is associated with inhalation of vapors in the pure form.[17][18][19] The State of New York has adopted a first-in-the-nation drinking water standard for 1,4-Dioxane and set the maximum contaminant level of 1 part per billion.[20]
Explosion hazard
editLike some other ethers, dioxane combines with atmospheric oxygen upon prolonged exposure to air to form potentially explosive peroxides. Distillation of these mixtures is dangerous. Storage over metallic sodium could limit the risk of peroxide accumulation.
Environment
editDioxane tends to concentrate in the water and has little affinity for soil. It is resistant to abiotic degradation in the environment, and was formerly thought to also resist biodegradation. However, more recent studies since the 2000s have found that it can be biodegraded through a number of pathways, suggesting that bioremediation can be used to treat 1,4-dioxane contaminated water.[21][22]
Dioxane has affected groundwater supplies in several areas. Dioxane at the level of 1 μg/L (~1 ppb) has been detected in many locations in the US.[5] In the U.S. state of New Hampshire, it had been found at 67 sites in 2010, ranging in concentration from 2 ppb to over 11,000 ppb. Thirty of these sites are solid waste landfills, most of which have been closed for years. In 2019, the Southern Environmental Law Center successfully sued Greensboro, North Carolina's Wastewater treatment after 1,4-Dioxane was found at 20 times above EPA safe levels in the Haw River.[23]
Cosmetics
editAs a byproduct of the ethoxylation process, a route to some ingredients found in cleansing and moisturizing products, dioxane can contaminate cosmetics and personal care products such as deodorants, perfumes, shampoos, toothpastes and mouthwashes.[24][25] The ethoxylation process makes the cleansing agents, such as sodium laureth sulfate and ammonium laureth sulfate, less abrasive and offers enhanced foaming characteristics. 1,4-Dioxane is found in small amounts in some cosmetics, a yet unregulated substance used in cosmetics in both China and the U.S.[26] Research has found the chemical in ethoxylated raw ingredients and in off-the-shelf cosmetic products. The Environmental Working Group (EWG) found that 97% of hair relaxers, 57% of baby soaps and 22 percent of all products in Skin Deep, their database for cosmetic products, are contaminated with 1,4-dioxane.[27]
Since 1979 the U.S. Food and Drug Administration (FDA) have conducted tests on cosmetic raw materials and finished products for the levels of 1,4-dioxane.[28] 1,4-Dioxane was present in ethoxylated raw ingredients at levels up to 1410 ppm (~0.14%wt), and at levels up to 279 ppm (~0.03%wt) in off the shelf cosmetic products.[28] Levels of 1,4-dioxane exceeding 85 ppm (~0.01%wt) in children's shampoos indicate that close monitoring of raw materials and finished products is warranted.[28] While the FDA encourages manufacturers to remove 1,4-dioxane, it is not required by federal law.[29]
On 9 December 2019, New York passed a bill to ban the sale of cosmetics with more than 10 ppm of 1,4-dioxane as of the end of 2022. The law will also prevent the sale of household cleaning and personal care products containing more than 2 ppm of 1,4-dioxane at the end of 2022.[30]
See also
edit
References
edit- ^ a b c d e f g h NIOSH Pocket Guide to Chemical Hazards. "#0237". National Institute for Occupational Safety and Health (NIOSH).
- ^ a b "Dioxane". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
- ^ Wisconsin Department of Health Services (2013) 1,4-Dioxane Fact Sheet Archived 16 October 2020 at the Wayback Machine. Publication 00514. Accessed 2016-11-12.
- ^ a b c d Surprenant, Kenneth S. (2000). "Dioxane". Dioxane in Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a08_545. ISBN 978-3527306732.
- ^ a b "1, 4-Dioxane Fact Sheet: Support Document" (PDF). OPPT Chemical Fact Sheets. United States Environmental Protection Agency. February 1995. Retrieved 14 May 2010.
- ^ Klaus Weissermel, Hans-Jürgen Arpe (2003) "Industrial Organic Chemistry". John Wiley & Sons, page 158. ISBN 3527305785, 9783527305780.
- ^ Schneider, Charles H.; Lynch, Cecil C. (1943). "The Ternary System: Dioxane—Ethanol—Water". Journal of the American Chemical Society. 65 (6): 1063–1066. doi:10.1021/ja01246a015.
- ^ Fischer, Reinald; Görls, Helmar; Meisinger, Philippe R.; Suxdorf, Regina; Westerhausen, Matthias (2019). "Structure–Solubility Relationship of 1,4-Dioxane Complexes of Di(hydrocarbyl)magnesium". Chemistry – A European Journal. 25 (55): 12830–12841. doi:10.1002/chem.201903120. PMC 7027550. PMID 31328293.
- ^ Cope, Arthur C. (1935). "The Preparation of Dialkylmagnesium Compounds from Grignard Reagents". Journal of the American Chemical Society. 57 (11): 2238. doi:10.1021/ja01314a059.
- ^ Anteunis, M. (1962). "Studies of the Grignard Reaction. II. Kinetics of the Reaction of Dimethylmagnesium with Benzophenone and of Methylmagnesium Bromide-Magnesium Bromide with Pinacolone". The Journal of Organic Chemistry. 27 (2): 596. doi:10.1021/jo01049a060.
- ^ Shimizu, A.; Ikeguchi, M.; Sugai, S. (1994). "Appropriateness of DSS and TSP as internal references for 1H NMR studies of molten globule proteins in aqueous media". Journal of Biomolecular NMR. 4 (6): 859–62. doi:10.1007/BF00398414. PMID 22911388. S2CID 34800494.
- ^ "International Chemical Safety Card". National Institute for Occupational Safety and Health. Archived from the original on 29 April 2005. Retrieved 6 February 2006.
- ^ Buffler, Patricia A.; Wood, Susan M.; Suarez, Lucina; Kilian, Duane J. (April 1978). "Mortality Follow-up of Workers Exposed to 1,4-Dioxane". Journal of Occupational and Environmental Medicine. 20 (4): 255–259. PMID 641607. Retrieved 26 March 2016.
- ^ "12th Report on Carcinogens". United States Department of Health and Human Services' National Toxicology Program. Archived from the original on 14 July 2014. Retrieved 11 July 2014.
- ^ IARC Monographs Volume 71 (PDF). International Agency for Research on Cancer. Retrieved 11 July 2014.
- ^ 1,4-Dioxane (1,4-Diethyleneoxide). Hazard Summary. U.S. Environmental Protection Agency. Created in April 1992; Revised in January 2000. Fact Sheet.
- ^ Kano, Hirokazu; Umeda, Yumi; Saito, Misae; Senoh, Hideki; Ohbayashi, Hisao; Aiso, Shigetoshi; Yamazaki, Kazunori; Nagano, Kasuke; Fukushima, Shoji (2008). "Thirteen-week oral toxicity of 1,4-dioxane in rats and mice". The Journal of Toxicological Sciences. 33 (2): 141–53. doi:10.2131/jts.33.141. PMID 18544906.
- ^ Kasai, T; Saito, M; Senoh, H; Umeda, Y; Aiso, S; Ohbayashi, H; Nishizawa, T; Nagano, K; Fukushima, S (2008). "Thirteen-week inhalation toxicity of 1,4-dioxane in rats". Inhalation Toxicology. 20 (10): 961–71. Bibcode:2008InhTx..20..961K. doi:10.1080/08958370802105397. PMID 18668411. S2CID 86811931.
- ^ Kasai, T.; Kano, H.; Umeda, Y.; Sasaki, T.; Ikawa, N.; Nishizawa, T.; Nagano, K.; Arito, H.; Nagashima, H.; Fukushima, S. (2009). "Two-year inhalation study of carcinogenicity and chronic toxicity of 1,4-dioxane in male rats". Inhalation Toxicology. 21 (11): 889–97. Bibcode:2009InhTx..21..889K. doi:10.1080/08958370802629610. PMID 19681729. S2CID 45963495.
- ^ "Governor Cuomo Announces First in the Nation Drinking Water Standard for Emerging Contaminant 1,4-Dioxane | Governor Andrew M. Cuomo". Archived from the original on 29 October 2020. Retrieved 30 October 2020.
- ^ Zenker, Matthew J.; Borden, Robert C.; Barlaz, Morton A. (September 2003). "Occurrence and Treatment of 1,4-Dioxane in Aqueous Environments". Environmental Engineering Science. 20 (5): 423–432. doi:10.1089/109287503768335913.
- ^ Zhang, Shu; Gedalanga, Phillip B.; Mahendra, Shaily (December 2017). "Advances in bioremediation of 1,4-dioxane-contaminated waters". Journal of Environmental Management. 204 (Pt 2): 765–774. doi:10.1016/j.jenvman.2017.05.033. PMID 28625566.
- ^ "1,4-dioxane in Greensboro | Haw River Assembly". 18 November 2020. Retrieved 13 May 2022.
- ^ Tenth Report on Carcinogens Archived 1 November 2004 at the Wayback Machine. U.S. Department of Health and Human Services, Public Health Service, National Toxicology Program, December 2002.
- ^ "Chemical Encyclopedia: 1,4-dioxane". Healthy Child Healthy World. Archived from the original on 29 November 2009. Retrieved 14 December 2009.
- ^ "Watchdog issues inspection results on Johnson & Johnson". China Daily. Xinhua. 21 March 2009. Retrieved 14 May 2010.
- ^ "The Dangers of 1,4-Dioxane and How to Avoid It". Aspen Clean. Aspen Clean. 11 February 2020. Retrieved 17 December 2020.
- ^ a b c Black, RE; Hurley, FJ; Havery, DC (2001). "Occurrence of 1,4-dioxane in cosmetic raw materials and finished cosmetic products". Journal of AOAC International. 84 (3): 666–70. doi:10.1093/jaoac/84.3.666. PMID 11417628.
- ^ FDA/CFSAN--Cosmetics Handbook Part 3: Cosmetic Product-Related Regulatory Requirements and Health Hazard Issues. Prohibited Ingredients and other Hazardous Substances: 9. Dioxane Web.archive.org
- ^ "New York restricts 1,4-dioxane in cleaning and personal care products". Cen.acs.org. Retrieved 13 November 2021.