Chemistry:2-Butoxyethanol

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Short description: Chemical compound
2-Butoxyethanol
2-Butoxyethanol
2-Butoxyethanol molecule
Names
Preferred IUPAC name
2-Butoxyethanol
Other names
2-Butoxyethanol
Butyl cellosolve
Butyl glycol
Butyl monoether glycol
EGBE (ethylene glycol monobutyl ether)
Dowanol EB
Eastman EB solvent
2-BE
EGMBE
Butyl oxitol
Ektasolve EB
Jeffersol EB
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
EC Number
  • 203-905-0
RTECS number
  • KJ8575000
UNII
UN number 1993, 2810, 2369
Properties
C6H14O2
Molar mass 118.176 g·mol−1
Appearance Clear, colorless liquid
Density 0.90 g/cm3, liquid
Melting point −77 °C (−107 °F; 196 K)
Boiling point 171 °C (340 °F; 444 K)
Miscible (and in most organic solvents)
Vapor pressure 0.8 mmHg[1]
Acidity (pKa) High pKa for −OH group
1.4198 (20 °C)[2]
Viscosity 2.9 cP at 25 °C (77 °F)
2.08 D[2]
Hazards
Safety data sheet [1]
GHS pictograms GHS06: ToxicGHS07: HarmfulGHS08: Health hazard
GHS Signal word Danger
H227, H302, H311, H315, H319, H330, H336, H361, H370, H372
P201, P202, P210, P260, P261, P264, P270, P271, P280, P281, P284, P301+312, P302+352, P304+340, P305+351+338, P307+311, P308+313, P310, P312, P314, P320, P321, P322, P330, P332+313
NFPA 704 (fire diamond)
Flammability code 2: Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur. Flash point between 38 and 93 °C (100 and 200 °F). E.g. diesel fuelHealth code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no codeNFPA 704 four-colored diamond
2
2
0
Flash point 67 °C (153 °F; 340 K)
245 °C (473 °F; 518 K)
Explosive limits 1.1–12.7%[1]
Lethal dose or concentration (LD, LC):
1230 mg/kg (mouse, oral)
470 mg/kg (rat, oral)
300 mg/kg (rabbit, oral)
1200 mg/kg (guinea pig, oral)
1480 mg/kg (rat, oral)[3]
450 ppm (rat, 4 hr)
700 ppm (mouse, 7 hr)[3]
NIOSH (US health exposure limits):
PEL (Permissible)
 TWA 50 ppm (240 mg/m3) [skin][1]
REL (Recommended)
 TWA 5 ppm (24 mg/m3) [skin][1]
IDLH (Immediate danger)
 700 ppm[1]
Related compounds
Related ethers
 2-Methoxyethanol
2-Ethoxyethanol
Related compounds
 Ethylene glycol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is ☑Y☒N ?)
Infobox references
Tracking categories (test):

2-Butoxyethanol is an organic compound with the chemical formula BuOC2H4OH (Bu = CH3CH2CH2CH2). This colorless liquid has a sweet, ether-like odor, as it derives from the family of glycol ethers, and is a butyl ether of ethylene glycol. As a relatively nonvolatile, inexpensive solvent, it is used in many domestic and industrial products because of its properties as a surfactant. It is a known respiratory irritant[4] and can be acutely toxic, but animal studies did not find it to be mutagenic, and no studies suggest it is a human carcinogen.[5] A study of 13 classroom air contaminants conducted in Portugal reported a statistically significant association with increased rates of nasal obstruction and a positive association below the level of statistical significance with a higher risk of obese asthma and increased child BMI.[6]

Production

2-Butoxyethanol is commonly obtained through two processes; the ethoxylation reaction of butanol and ethylene oxide in the presence of a catalyst:

C2H4O + C4H9OH → C4H9OC2H4OH

or the etherification of butanol with 2-chloroethanol.[7] 2-Butoxyethanol can be obtained in the laboratory by performing a ring opening of 2-propyl-1,3-dioxolane with boron trichloride.[8] It is often produced industrially by combining ethylene glycol and butyraldehyde in a Parr reactor with palladium on carbon.[9]

In 2006, the European production of butyl glycol ethers amounted to 181 kilotons, of which approximately 50% (90 kt/a) was 2-butoxyethanol. World production is estimated to be 200 to 500 kt/a, of which 75% is for paints and coatings[10] and 18% for metal cleaners and household cleaners.[11] In the US, it is considered a high production volume chemical because more than 100 million pounds of this chemical are produced per year.[11]

Uses

2-Butoxyethanol is a glycol ether with modest surfactant properties, which can also be used as a mutual solvent.[clarification needed]

Commercial uses

2-Butoxyethanol is a solvent for paints and surface coatings, as well as cleaning products and inks.[10][12] Products that contain 2-butoxyethanol include acrylic resin formulations, asphalt release agents, firefighting foam, leather protectors, oil spill dispersants, degreaser applications, photographic strip solutions, whiteboard and glass cleaners, liquid soaps, cosmetics, dry cleaning solutions, lacquers, varnishes, herbicides, latex paints, enamels, printing paste, and varnish removers, and silicone caulk. Products containing this compound are commonly found at construction sites, automobile repair shops, print shops, and facilities that produce sterilizing and cleaning products. It is the main ingredient of many home, commercial and industrial cleaning solutions. Since the molecule has both polar and non-polar ends, 2-butoxyethanol is useful for removing both polar and non-polar substances, like grease and oils. It is also approved by the U.S. FDA to be used as direct and indirect food additives, which include antimicrobial agents, defoamers, stabilizers, and adhesives.[13]

In the petroleum industry

2-Butoxyethanol is commonly produced for the oil industry because of its surfactant properties.[14]

In the petroleum industry, 2-butoxyethanol is a component of fracturing fluids, drilling stabilizers, and oil slick dispersants for both water-based and oil-based hydraulic fracturing.[11][clarification needed] When liquid is pumped into the well, the fracturing fluids are pumped under extreme pressure, so 2-butoxyethanol is used to stabilize them by lowering the surface tension.[11] As a surfactant, 2-butoxyethanol absorbs at the oil-water interface of the fracture.[15] The compound is also used to facilitate the release of the gas by preventing congealing.[11] It is also used as a crude oil–water coupling solvent for more general oil well workovers.[11] Because of its surfactant properties, it is a major constituent (30–60% w/w) in the oil spill dispersant Corexit 9527,[16] which was widely used in the aftermath of the 2010 Deepwater Horizon oil spill.[13]

Safety

2-Butoxyethanol has a low acute toxicity, with -1">50 of 2.5 g/kg in rats.[10] Laboratory tests by the U.S. National Toxicology Program have shown that only sustained exposure to high concentrations (100–500 ppm) of 2-butoxyethanol can cause adrenal tumors in animals.[17] American Conference of Governmental Industrial Hygienists (ACGIH) reports that 2-butoxyethanol is carcinogenic in rodents.[18] These rodent tests may not directly translate to carcinogenicity in humans, as the observed mechanism of cancer involves the rodents' forestomach, which humans lack.[19] OSHA does not regulate 2-butoxyethanol as a carcinogen.[20] 2-Butoxyethanol has not been shown to penetrate shale rock in a study conducted by Manz.[21]

Disposal and degradation

2-Butoxyethanol can be disposed of by incineration. It was shown that disposal occurs faster in the presence of semiconductor particles.[7] 2-Butoxyethanol usually decomposes in the presence of air within a few days by reacting with oxygen radicals.[22] It has not been identified as a major environmental contaminant, nor is it known to bio-accumulate.[23] 2-Butoxyethanol biodegrades in soils and water, with a half life of 1–4 weeks in aquatic environments.[13]

Human exposure

2-Butoxyethanol most commonly enters the human body system through dermal absorption, inhalation, or oral consumption of the chemical.[7] The ACGIH threshold limit value (TLV) for worker exposure is 20 ppm, which is well above the odor detection threshold of 0.4 ppm. Blood or urine concentrations of 2-butoxyethanol or the metabolite 2-butoxyacetic acid may be measured using chromatographic techniques. A biological exposure index of 200 mg 2-butoxyacetic acid per g creatinine has been established in an end-of-shift urine specimen for U.S. employees.[24][25] 2-Butoxyethanol and its metabolites fall to undetectable levels in urine after about 30 hours in men.[26]

Animal studies

Harmful effects have been observed in nonhuman mammals exposed to high levels of 2-butoxyethanol. Developmental effects were seen in a study that exposed pregnant Fischer 344 rats, a type of laboratory rat, and New Zealand white rabbits to varying doses of 2-butoxyethanol. At 100 ppm (483 mg/m3) and 200 ppm (966 mg/m3) exposure, statistically significant increases were observed in the number of litters with skeletal defects. Additionally, 2-butoxyethanol was associated with a significant decrease in maternal body weight, uterine weight, and number of total implants.[27] 2-Butoxyethanol is metabolized in mammals by the enzyme alcohol dehydrogenase.[26]

Neurological effects have also been observed in animals exposed to 2-butoxyethanol. Fischer 344 rats exposed to 2-butoxyethanol at concentrations of 523 ppm and 867 ppm experienced decreased coordination. Male rabbits showed a loss of coordination and equilibrium after exposure to 400 ppm of 2-butoxyethanol for two days.[28]

When exposed to 2-butoxyethanol in drinking water, both F344/N rats and B63F1 mice showed negative effects. The range of exposure for the two species was between 70 mg/kg body weight per day to 1300 mg/kg body weight per day. Decreased body weight and water consumption were seen for both species. Rats had reduced red blood cell counts and thymus weights, as well as lesions in the liver, spleen, and bone marrow.[27]

Regulation in Canada

Environment and Health Canada recommended that 2-butoxyethanol be added to Schedule 1 of the Canadian Environmental Protection Act, 1999 (CEPA).[29] Under these regulations, products containing 2-butoxyethanol are to be diluted below a certain concentration. Only those in which the user performs the required dilution are required to include it on labelling information.[30]

Regulation in the US

2-Butoxyethanol is listed in California as a hazardous substance and the state sets an 8 hour average airborne concentration exposure limit at 25 ppm,[31] and in California employers are required to inform employees when they are working with it.[32]

It is approved by the Food and Drug Administration as "an indirect and direct food additive for use as an antimicrobial agent, defoamer, stabilizer and component of adhesives",[13] and also "may be used to wash or assist in the peeling of fruits and vegetables" and "may be safely used as components of articles intended for use in packaging, transporting & holding food".[33] After its deletion from a UN list of substances requiring special toxicity labeling in 1994, and a subsequent petition by the American Chemistry Council, 2-butoxyethanol was removed from the U.S. Environmental Protection Agency's list of hazardous air pollutants in 2004.[34][35] The safety of products containing 2-butoxyethanol as normally used is defended by the industry trade groups the American Chemistry Council[35] and the Soap and Detergent Association.

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 NIOSH Pocket Guide to Chemical Hazards. "#0070". National Institute for Occupational Safety and Health (NIOSH). https://www.cdc.gov/niosh/npg/npgd0070.html. 
  2. ↑ 2.0 2.1 CRC handbook of chemistry and physics : a ready-reference book of chemical and physical data.. William M. Haynes, David R. Lide, Thomas J. Bruno (2016-2017, 97th ed.). Boca Raton, Florida. 2016. ISBN 978-1-4987-5428-6. OCLC 930681942. https://www.worldcat.org/oclc/930681942. 
  3. ↑ 3.0 3.1 "2-Butoxyethanol". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH). https://www.cdc.gov/niosh/idlh/111762.html. 
  4. ↑ "TOXNET HAS MOVED". https://www.nlm.nih.gov/toxnet/index.html. 
  5. ↑ "Public Health Statement for 2-Butoxyethanol and 2-Butoxyethanol Acetate". August 1998. https://www.atsdr.cdc.gov/phs/phs.asp?id=345&tid=61. 
  6. ↑ Paciência, Inês; Cavaleiro Rufo, João; Silva, Diana; Martins, Carla; Mendes, Francisca; Farraia, Mariana; Delgado, Luís; De Oliveira Fernandes, Eduardo et al. (2019). "Exposure to indoor endocrine-disrupting chemicals and childhood asthma and obesity". Allergy 74 (7): 1277–1291. doi:10.1111/all.13740. PMID 30740706. 
  7. ↑ 7.0 7.1 7.2 Harris O. (August 1998). Toxicological Profile for 2-Butoxyethanol and 2-butoxyethanol acetate. U.S. Dept of Health and Human Services. 
  8. ↑ Bonner, Trevor (1981). "Opening of cyclic acetals by trichloro-, dichloro-, and tribromo-borane". Journal of the Chemical Society, Perkin Transactions 1: 1807–1810. doi:10.1039/p19810001807. 
  9. ↑ Tulchinsky, Michael (2014), Poly ethers and process for making them, https://patents.google.com/patent/US8829229B2/en 
  10. ↑ 10.0 10.1 10.2 Siegfried Rebsdat, Dieter Mayer "Ethylene Glycol" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2000.doi:10.1002/14356007.a10_101.
  11. ↑ 11.0 11.1 11.2 11.3 11.4 11.5 "Ethylene Glycol Mono-N-Butyl Ether". National Library of Medicine. http://toxnet.nlm.nih.gov/cgi-bin/sis/search/f?./temp/~0Bg03b:1. 
  12. ↑ "Sharpie Frequently Asked Questions". sharpie.com. http://www.sharpie.com/enus/Pages/FAQ.aspx#Q15. 
  13. ↑ 13.0 13.1 13.2 13.3 Dickey, Robert W.; Dickhoff, Walton W. (2012-01-30). "Dispersants and Seafood Safety Assessment of the potential impact of COREXIT oil dispersants on seafood safety" (in en-us). Mobile, Alabama: Dispersant Initiative and Workshop “The Future of Dispersant Use in Spill Response” (Tuesday, September 20, 2011 to Thursday, September 22, 2011). https://www.crrc.unh.edu/sites/crrc.unh.edu/files/dickeydickhoff.pdf. 
  14. ↑ Rogers, J (2015). "A Framework for Identifying Organic Compounds of Concern in Hydraulic Fracturing Fluids Based on Their Mobility and Persistence in Groundwater". Environmental Science and Technology Letters 2 (6): 158–164. doi:10.1021/acs.estlett.5b00090. Bibcode: 2015EnSTL...2..158R. 
  15. ↑ Barati, Reza (2014). "A review of fracturing fluid systems used for hydraulic fracturing of oil and gas wells". Journal of Applied Polymer Science 131 (16): n/a. doi:10.1002/app.40735. 
  16. ↑ "SAFETY DATA SHEET - PRODUCT: COREXIT EC9527A". Nalco Environmental Solutions LLC. 1 March 2012. http://www.nalcoesllc.com/nes/documents/MSDS/NESLLC-COREXIT-_EC9527A-March_2012.pdf. 
  17. ↑ "Toxicology and Carcinogenesis Studies 2-Butoxyethanol (CAS NO. 111-76-2) in F344/N Rats and B6C3F1 Mice (Inhalation Studies)". National Toxicology Program: Department of Health and Human Services. USA.gov. https://ntp.niehs.nih.gov/go/tr484abs. 
  18. ↑ "Air Foam HD Material Data Safety Sheet". Product Safety. AquaClear, Inc. https://archive.org/details/AirFoamHdMaterialDataSafetySheetmsds. 
  19. ↑ Gift, J. S. (2005). "U.S. EPA's IRIS assessment of 2-Butoxyethanol: the relationship of noncancer to cancer effects". Toxicol. Lett. 156 (1): 163–178. doi:10.1016/j.toxlet.2003.08.014. PMID 15705494. http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1168&context=usepapapers. 
  20. ↑ "Chemical Sampling Information | 2-Butoxyethanol". Occupational Safety & Health Administration. https://www.osha.gov/dts/chemicalsampling/data/CH_222400.html. 
  21. ↑ Manz, K (2016). "Adsorption of hydraulic fracturing fluid components 2-butoxyethanol and furfural onto granular activated carbon and shale rock". Chemosphere 164: 585–592. doi:10.1016/j.chemosphere.2016.09.010. PMID 27632795. Bibcode: 2016Chmsp.164..585M. 
  22. ↑ Hullar, T.; Anastasio, C. (2011-07-22). "Yields of hydrogen peroxide from the reaction of hydroxyl radical with organic compounds in solution and ice" (in English). Atmospheric Chemistry and Physics 11 (14): 7209–7222. doi:10.5194/acp-11-7209-2011. ISSN 1680-7316. Bibcode: 2011ACP....11.7209H. https://acp.copernicus.org/articles/11/7209/2011/. 
  23. ↑ "ATSDR - ToxFAQs: 2-Butoxyethanol and 2-Butoxyethanol Acetate". cdc.gov. https://wwwn.cdc.gov/TSP/ToxFAQs/ToxFAQsLanding.aspx?id=346&tid=61. 
  24. ↑ 2009 TLVs and BEIs, American Conference of Industrial Hygienists, Cincinnati, Ohio, 2009, p.101.
  25. ↑ R. Baselt (2008). Disposition of Toxic Drugs and Chemicals in Man (8th ed.). Foster City, CA: Biomedical Publications. pp. 208–210. 
  26. ↑ 26.0 26.1 Franks, S. J.; Spendiff, M. K.; Cocker, J.; Loizou, G. D. (2006). "Physiologically based pharmacokinetic modelling of human exposure to 2-butoxyethanol". Toxicol. Lett. 162 (2–3): 164–173. doi:10.1016/j.toxlet.2005.09.012. PMID 16246510. 
  27. ↑ 27.0 27.1 Wess, Ms. J., Dr. H. Ahlers, and Dr. S Dobson. "Concise International Chemical Assessment Document 10: 2-Butoxyethanol." World Health Organization, n.d. Web. <http://www.who.int/ipcs/publications/cicad/cicad_10_revised.pdf>
  28. ↑ United States of America. Agency for Toxic Substances and Disease Registry. Department of Health and Human Services. Toxicological Profile for 2-Butoxyethanol and 2-Butoxyethanol Acetate. By Olivia Harris, Sharon Wilbur, Julia George, and Carol Eisenmann. Atlanta: n.p., 1998. Agency for Toxic Substances and Disease Registry. Web. <http://www.atsdr.cdc.gov/toxprofiles/tp118.pdf>
  29. ↑ "Current Use Patterns in Canada, Toxicology Profiles of Alternatives, and the Feasibility of Performing an Exposure Assessment Survey". Environment Canada. 2017-03-12. http://www.chemicalsubstanceschimiques.gc.ca/fact-fait/butoxyethanol-eng.php. 
  30. ↑ "Regulations Amending the 2-Butoxyethanol Regulations". Canadian Department of Public Works and Government Services. 23 April 2014. http://www.gazette.gc.ca/rp-pr/p2/2014/2014-04-23/html/sor-dors78-eng.php. 
  31. ↑ "California Code of Regulations, Title 8, Section 339. The Hazardous Substances List". State of California Department of Laboring Relations. http://www.dir.ca.gov/title8/339.html. 
  32. ↑ "Glycol Ethers Fact Sheet". California Hazard Evaluation and Information Service. http://www.dhs.ca.gov/ohb/HESIS/glycols.htm. 
  33. ↑ CFR Title 21 - Food and Drugs - URL: http://www.fda.gov (2004). CFR Title: 21 CFR Part Section: 173.315
  34. ↑ "List of Hazardous Air Pollutants, Petition Process, Lesser Quantity Designations, Source Category List; Petition To Delist of Ethylene Glycol Monobutyl Ether". U.S. Environmental Protection Agency. 2004-11-29. http://www.epa.gov/EPA-AIR/2004/November/Day-29/a26071.htm. 
  35. ↑ 35.0 35.1 "EGBE: A World of Solutions 2000". July 2000. http://www.egep.org/worldsolutions2000.pdf. 

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