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From Wikipedia, the free encyclopedia

1,4-Dioxane
Names
Preferred IUPAC name
1,4-Dioxane
Other names
1,4-Dioxacyclohexane
[1,4]Dioxane
p-Dioxane
[6]-crown-2
Diethylene dioxide
Diethylene ether
Dioxan
Identifiers
3D model (JSmol)
102551
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.004.239
EC Number 204-661-8
KEGG
RTECS number JG8225000
UNII
UN number 1165
Properties
C4H8O2
Molar mass 88.106 g·mol−1
Appearance Colorless liquid[1]
Odor Mild, 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
196.6 J/K·mol
−354 kJ/mol
−2363 kJ/mol
Hazards
Main hazards Carcinogen[1]
GHS pictograms
GHS02: Flammable
GHS07: Harmful
GHS08: Health hazard
GHS signal word Danger
H225, H315, H319, H332, H336, H351, H370, H372, H373
P201, P202, P210, P233, P240, P241, P242, P243, P260, P261, P264, P270, P271, P280, P281, P302+352, P303+361+353, P304+312, P304+340, P305+351+338, P307+311, P308+313, P312, P314, P321
NFPA 704
Flammability code 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g., gasolineHealth code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroformReactivity code 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g., calciumSpecial hazards (white): no codeNFPA 704 four-colored diamond
3
2
1
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):
  • 5.7 g/kg (mouse, oral)
  • 5.2 g/kg (rat, oral)
  • 3.9 g/kg (guinea pig, oral)
  • 7.6 g/kg (rabbit, dermal)
  • 10,109 ppm (mouse, 2 hr)
  • 12,568 ppm (rat, 2 hr)[2]
1000–3000 ppm (guinea pig, 3 hr)

12,022 ppm (cat, 7 hr)
2085 ppm (mouse, 8 hr)[2]

US health exposure limits (NIOSH):
PEL (Permissible)
TWA 100 ppm (360 mg/m3) [skin][1]
REL (Recommended)
Ca C 1 ppm (3.6 mg/m,3) [30-minute][1]
IDLH (Immediate danger)
Ca [500 ppm][1]
Related compounds
Related compounds
Oxane
Trioxane
Tetroxane
Pentoxane
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☑Y verify (what is ☑Y☒N ?)
Infobox references

1,4-Dioxane (/dˈɒksn/) 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.

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 aluminum containers.[3]

YouTube Encyclopedic

  • 1/3
    Views:
    99 066
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  • ✪ Make Dioxane from Antifreeze
  • ✪ 1,4-Dioxane
  • ✪ Make Sodium Metal Without Electrolysis Using Domestic Chemicals

Transcription

The video sponsored by the great courses plus. A video on demand learning service featuring lectures from top professors. Warning: Sulfuric acid is corrosive, ethylene glycol is poisonous, dioxane is carcinogenic. Wear gloves when handling them. This experiment also generates volatile side products. Work outside or in a fume hood. Greetings fellow nerds. Dioxane is an easy to make cyclic ether. It's not as popular as diethyl ether. And it is somewhat more toxic and carcinogenic. But it does have its uses. And because it's easy to make, even for the amature, we're going to make it in this video. Briefly, all we're really going to do, is take two ethylene glycol molecules and join them together. They're essentially two halves of one dioxane molecule. First we start with 300mL of antifreeze. Make sure the label says it's made with ethylene glycol. And get the concentrated type and not the premixed version which has water added. Now we add in 30 to 40 ml of concentrated sulfuric acid. I'm using low grade drain cleaner acid, you can even use diluted acid as long as you add the appropriate extra amount. Any water present will be boiled off. Now around the flask we set up a distillation apparatus. Turn on the cooling water, the heating and the stirring and raise the temperature until the mixture starts to boil. Adjust the heating so that you get around one drop of distillate every 2 or 3 seconds. Going by distillate temperature is not very reliable because at the beginning of the procedure the distillate temperature is not very stable. Water, impurities as well as any additives in the antifreeze will start reacting first and boiling off. It's not until they've all distilled off that the distillate temperature starts to converge and the ethylene glycol starts reacting and forming our desired product. What's happening is the sulfuric acid is catalyzing the dehydration of ethylene glycol to produce dioxane and water. Both of these have lower boiling points than the reactants and thus they distill off and drive the reaction forward. This reaction is very robust and even using raw antifreeze with dirty sulfuric acid will work. You don't even need to distill your antifreeze first to make pure ethylene glycol. The reaction also scales well with temperature and if you're impatient you can increase the heating to improve the rate. I'm going with this rather slow rate to minimize byproducts. But considering how cheap the starting chemicals are, i'll let you make the judgement call if you prefer speed over yield. Now you might be asking if sodium bisulfate will work as a catalyst. The motivation being it's easier to get as a pH lowering chemical for swimming pools. I actually did try it and it did work. But it required much higher temperatures and worked much slower than actual sulfuric acid. So i strongly recommend using sulfuric acid if you can. Now as the reaction progresses it will generate a tar of byproducts. When this starts to foam excessively you'll need to stop the reaction. You can adjust stirring and get a temporary reprieve but eventually it'll be too much too continue. Turn off the heating and let it cool. And just so you know, you can clean out the tar with sodium hydroxide based drain cleaner. It's nearly impossible to get out with water alone. And here is our distillate of dioxane and water. Our work is just beginning though, most of the work is in the purification. This mixture contains numerous side products so we to need to separate them as well as get rid of the excess water. Add directly to this mixture 10mL of sulfuric acid. This will acidify the side products and hydrolyze them for easier separation. Now setup a fractional distillation apparatus around the mixture and start distilling. Now one of the major side products is acetaldehyde. This was formed by dehydration of ethylene glycol and distills off at around 20 celsius. You're not seeing a clean temperature plateau for the distillation because i'm just cranking the heat and blasting through it. I have no use for acetaldehyde and it'll likely be contaminated with other impurities, as well as any additives that are boiling off now as well. It's also toxic and carcinogenic so i don't even want to keep it around. Anyway, the reason why we added sulfuric acid at the beginning is to hydrolyze another side product. 2-Methyl-1,3-dioxolane, this was formed from the reaction of acetaldehyde and ethylene glycol. Under acidic conditions with lots of water it'll hydrolyze back into the ethylene glycol and acetaldehyde, allowing us to remove it. You might be asking why it wasn't destroyed in the acidic conditions of the original reaction mixture. It was acidic but it had no water as the water was constantly being boiled off as it was formed. But our distillate has lots of water so we can destroy it here. Okay, keep distilling until you reach about 84 celsius and then change out the receiver. You can see we have a lot acetaldehyde and other side products so fractional distillation is absolutely necessary for purification. Alright, dioxane and water have a low boiling azeotrope at 87 celsius. So distill past that and change out the receiver at about 94 celsius before stopping the distillation. The rest is mostly water and other impurities. And here is our azeotropic mixture of about 17.9% water and 82.1% dioxane. Now we need to remove the rest of the water. Since this already an azeotropic mixture we can't use distillation. We're going to need a chemical method. Let me transfer this azeotrope to a larger container. Now we add in 40g of sodium hydroxide and stir. Sodium hydroxide absorbs the water and dissolves forming a separate layer from the dioxane. You'll also notice it's starting to change color. This orange stuff is actually any remaining impurities like acetaldehyde being polymerized by the sodium hydroxide. So this step not only removes water, but also the remaining impurities. It's also the reason why i'm not using a more powerful drying agent like molecular sieves. Molecular sieves only remove water, and not these other impurities. Okay looks like there was a lot of water and the sodium hydroxide solution has dissolved. I'm going to add in another 40g of sodium hydroxide and hope the mixture separates again. Now potassium hydroxide is even better for this and i recommend going with that if you can. I'm using sodium hydroxide because it's easier to get for the amateur. Okay looks like it separating, somewhat. I'm going to let this go overnight to try and remove as much water and impurities as possible. Okay here we are the next day and we can see we have nice and relatively clear layer of dioxane along with a gooey layer of sodium hydroxide, water and polymerized impurities. Decant off the dioxane into a new container. A disadvantage of a gooey mixture like this is that the goo has probably absorbed a lot of dioxane in it. Potassium hydroxide would be better as it would remain liquid and thus you can use a separatory funnel for better separation. Now at this point, to destroy the last remaining impurities, we would use sodium metal just like we did with purifying triethylamine. But pure sodium metal is very hard to get for the amateur so we're going to instead use the crude sodium mixed with magnesium oxide, made from magnesium and sodium hydroxide as i've shown in another video. This mixture will destroy any remaining water and reactive impurities and you can see it working from the bubbling here. I'm going to put it on stirring to smash apart the nuggets for greater reactivity. Now this will take some time to work so i'm going to let it go overnight. Here we are the next day. Now we setup for distillation and simply distill over the dioxane. And there we have it, high purity dioxane. Now a special note about storage. Dioxane, like most ethers, tends to form explosive peroxides on storage with air. It's a small amount, and mostly harmless because it's diluted, but you distill or dry off the dioxane at a latter date it will concentrate in the residues and explode. This is one of the sources for that old stereotype of chemistry labs constantly exploding. It's not entirely an urban legend. So to be on the safe side, don't let the dioxane sit for more than several months, use it up before then. Alternatively, store it over sodium metal if you have it. It can also be stored over sodium hydroxide. It'll last longer but shouldn't be ignored. I'll make a separate video on dealing with peroxides in ether solutions. Anyway, as you've seen, dioxane dissolves both water, polar and organic substances so it can be used for experiments requiring the combination of a diverse set of reagents. i want to use dioxane in my pyrimethamine synthesis although i have no idea if it'll work. We'll see what happens. Thanks for watching. This video was sponsored in part by the great courses plus. An online learning service featuring thousands videos by top university professors as well as experts in their respective fields. Subscription gives you unlimited access to a diverse set of fields from chemistry, to cooking to photography. For you chemistry lovers courses on important concepts like thermodynamics are available that you won't find on my channel. It's a great resource to round out your knowledge. As part of a special promotion with my channel. The Great Courses Plus is offering a free trial. You can check them out at this link "thegreatcoursesplus.com/nurdrage" or click on the link in my description below. These videos are also sponsored in large part by my patrons on Patreon. If you are not currently a patron, but like to support the continued production of science videos like this one, then check out my patreon page here or in the video description. I really appreciate any and all support.

Contents

Synthesis

Dioxane 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

The 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

Trichloroethane transport

In 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 aluminum trichloride.[4]

As a solvent

Binary phase diagram for the system 1,4-dioxane/water
Binary phase diagram for the system 1,4-dioxane/water

Dioxane is used in a variety of applications as a versatile aprotic solvent, e. g. for inks, adhesives, and cellulose esters.[6] 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).

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 Lewis-basic, and so dioxane is able to solvate many inorganic compounds and serves as a chelating diether ligand. It reacts with Grignard reagents to precipitate the magnesium dihalide. In this way, dioxane is used to drive the Schlenk equilibrium.[4] Dimethylmagnesium is prepared in this manner:[8][9]

2 CH3MgBr + (C2H4O)2 → MgBr2(C2H4O)2 + (CH3)2Mg

Spectroscopy

Dioxane is used as an internal standard for nuclear magnetic resonance spectroscopy in deuterium oxide.[10]

Toxicology

Safety

Dioxane has an LD50 of 5170 mg/kg in rats.[4] This compound is irritating to the eyes and respiratory tract. Exposure may cause damage to the central nervous system, liver and kidneys.[11] In a 1978 mortality study conducted on workers exposed to 1,4-dioxane, the observed number deaths from cancer was not significantly different from the expected number.[12] Dioxane is classified by the National Toxicology Program as "reasonably anticipated to be a human carcinogen".[13] 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.[14] 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.[15] Under California Proposition 65, dioxane is classified in the U.S. State of California to cause cancer.[16] Animal studies in rats suggest that the greatest health risk is associated with inhalation of vapors in the pure form.[17][18][19]

Explosion hazard

Like some other ethers, dioxane combines with atmospheric oxygen upon prolonged exposure to air to form potentially explosive peroxides. Distillation of dioxanes concentrates these peroxides, increasing the danger.

Environment

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 State of New Hampshire alone in 2010 it had been found at 67 sites, 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. It also has low toxicity to aquatic life and can be biodegraded via a number of pathways.[20] The problems are exacerbated since dioxane is highly soluble in water, does not readily bind to soils, and readily leaches to groundwater. It is also resistant to naturally occurring biodegradation processes. Due to these properties, a dioxane plume can be larger (and further downgradient) than the associated solvent plume.

Cosmetics

As 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.[21][22] 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.[23]

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.[24] 1,4-Dioxane was present in ethoxylated raw ingredients at levels up to 1410 ppm, and at levels up to 279 ppm in off the shelf cosmetic products.[24] Levels of 1,4-dioxane exceeding 85 ppm in children's shampoos indicate that close monitoring of raw materials and finished products is warranted.[24] While the FDA encourages manufacturers to remove 1,4-dioxane, it is not required by federal law.[25]

See also

The three isomers of dioxane
The three isomers of dioxane

References

  1. ^ a b c d e f g h NIOSH Pocket Guide to Chemical Hazards. "#0237". National Institute for Occupational Safety and Health (NIOSH).
  2. ^ a b "Dioxane". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  3. ^ Wisconsin Department of Health Services (2013) 1,4-Dioxane Fact Sheet. Publication 00514. Accessed on 2016-11-12.
  4. ^ 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.
  5. ^ 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.
  6. ^ Klaus Weissermel, Hans-Jürgen Arpe (2003) "Industrial Organic Chemistry". John Wiley & Sons, page 158. ISBN 3527305785, 9783527305780.
  7. ^ Schneider, C. H.; Lynch, C. C.: The Ternary System: Dioxane-Ethanol-Water in J. Am. Chem. Soc., 1943, vol. 65, pp 1063–1066. doi:10.1021/ja01246a015.
  8. ^ 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.
  9. ^ 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.
  10. ^ 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.
  11. ^ "International Chemical Safety Card". National Institute for Occupational Safety and Health. Archived from the original on 29 April 2005. Retrieved 6 February 2006.
  12. ^ 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. Retrieved 26 March 2016.
  13. ^ "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.
  14. ^ "IARC Monographs Volume 71" (PDF). International Agency for Research on Cancer. Retrieved 11 July 2014.
  15. ^ 1,4-Dioxane (1,4-Diethyleneoxide). Hazard Summary. U.S. Environmental Protection Agency. Created in April 1992; Revised in January 2000. Fact Sheet.
  16. ^ "Chemicals Known to the State to Cause Cancer or Reproductive Toxicity" (PDF). Office of Environmental Health Hazard Assessment. 2 April 2010. Archived from the original (PDF) on 24 May 2010. Retrieved 14 December 2013. 1,4-Dioxane CAS#123-91-1 (Listed January 1, 1988)
  17. ^ 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.
  18. ^ 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. doi:10.1080/08958370802105397. PMID 18668411.
  19. ^ 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. doi:10.1080/08958370802629610. PMID 19681729.
  20. ^ Kinne, Matthias; Poraj-Kobielska, Marzena; Ralph, Sally A.; Ullrich, René; Hofrichter, Martin; Hammel, Kenneth E. (2009). "Oxidative cleavage of diverse ethers by an extracellular fungal peroxygenase". The Journal of Biological Chemistry. 284 (43): 29343–9. doi:10.1074/jbc.M109.040857. PMC 2785565. PMID 19713216.
  21. ^ 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.
  22. ^ "Chemical Encyclopedia: 1,4-dioxane". Healthy Child Healthy World. Archived from the original on 29 November 2009. Retrieved 14 December 2009.
  23. ^ "Watchdog issues inspection results on Johnson & Johnson". China Daily. Xinhua. 21 March 2009. Retrieved 14 May 2010.
  24. ^ 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. PMID 11417628.
  25. ^ FDA/CFSAN--Cosmetics Handbook Part 3: Cosmetic Product-Related Regulatory Requirements and Health Hazard Issues. Prohibited Ingredients and other Hazardous Substances: 9. Dioxane
This page was last edited on 17 June 2019, at 12:52
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