2-Butoxyethanol

From Wikipedia, the free encyclopedia
  (Redirected from Ethylene glycol monobutyl ether)
Jump to: navigation, search
2-Butoxyethanol
2-Butoxyethanol
2-Butoxyethanol molecule
Identifiers
CAS number 111-76-2 YesY
ChemSpider 7841 YesY
UNII I0P9XEZ9WV YesY
ChEBI CHEBI:63921 YesY
RTECS number KJ8575000
Jmol-3D images Image 1
Properties
Molecular formula C6H14O2
Molar mass 118.17 g mol−1
Appearance Clear, colourless liquid
Density 0.90 g/cm³, liquid
Melting point −77 °C (−107 °F; 196 K)
Boiling point 171 °C (340 °F; 444 K)
Solubility in water Miscible
Acidity (pKa) high pKa for -OH group
Viscosity 2.9 cP at 25 °C (77 °F)
Hazards
MSDS MSDS by Mallinckrodt Baker
EU classification Harmful (Xn)
R-phrases R20/21/22, R36/38
S-phrases (S2), S36/37, S46
NFPA 704
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 fuel Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point 67 °C (153 °F; 340 K)
Related compounds
Related ethers 2-Methoxyethanol
2-Ethoxyethanol
Related compounds Ethylene glycol
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
Infobox references

2-Butoxyethanol is an organic compound with the 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.

Production[edit]

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

C2H4O + C4H9OH → C4H9OC2H4OH

or the etherification of butanol with 2-chloroethanol.[1]

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[2] and 18% for metal cleaners and household cleaners.[3] In the US, it is considered a High Production Volume Chemical because greater than 100 million pounds of this chemical is produced per year.[3]

Uses[edit]

2-Butoxyethanol is a glycol ether with modest surfactant properties. In use since the 1930s, glycol ethers are solvents that dissolve both water soluble and hydrophobic substances. Glycol ethers consist of two components, an alcohol and ether. According to the nature of alcohol, molecules of this class can be divided into two groups: E series and P series which correspond to ethylene and propylene respectively. Glycol ethers are selected for specific purposes, such as solubility, inflammability, and volatility.[4]

Commercial uses[edit]

2-Butoxyethanol was introduced into the industrial industry as a solvent for paints and surface coatings, as well as cleaning products and inks. Other 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 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.[3][5][6] It is the main ingredient of many home, commercial and industrial cleaning solutions. Since it has both a non-polar and a polar end, it is useful for removing both polar and non-polar substances, like grease and oils. It is also approved by the FDA in the United States to be used as direct and indirect food additives, which include antimicrobial agents, defoamers, stabilizers, and adhesives.[7]

In the petroleum industry[edit]

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[3][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.[3] The compound is also used to facilitate the release of the gas by preventing congealing.[3] It is also used as a crude oil-water coupling solvent for more general oil well workovers.[3] Because of its surfactant properties, it is a major constituent (30–60% w/w) in the oil spill dispersant Corexit 9527,[8] which was widely used in the aftermath of the 2010 Deepwater Horizon oil spill.[7]

Safety[edit]

2-Butoxyethanol has a low acute toxicity, with LD50 of 2.5 g/kg in rats.[2] 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.[9] American Conference of Governmental Industrial Hygienists (ACGIH) reports that 2-butoxyethanol is carcinogenic in animals.[10] However, these rodent tests may not directly translate to carcinogenicity in humans, as the observed mechanism of cancer involves the rodents' forestomach, which humans do not have.[11] OSHA does not regulate 2-butoxyethanol as a carcinogen.[12]

Disposal and degradation[edit]

2-Butoxyethanol can be disposed of by incineration. It was shown that disposal occurs faster in the presence of semiconductor particles.[1] 2-Butoxyethanol usually decomposes in the presence of air within a few days by reacting with oxygen radicals.[13] It has not been identified as a major environmental contaminant, nor is it known to bio-accumulate.[14] 2-Butoxyethanol biodegrades in soils and water, with a half life of 1–4 weeks in aquatic environments.[7]

Human exposure[edit]

Moderate respiratory exposure to 2-butoxyethanol often results in irritation of mucous membranes of the eyes, nose and throat. Heavy exposure via respiratory, dermal or oral routes can lead to hypotension, metabolic acidosis,[15] hemolysis, pulmonary edema and coma.[16] The current ACGIH threshold limit value (TLV) for worker exposure is 20 ppm in the industrial atmosphere, which is well above the odor detection threshold of 0.4 ppm. 2-Butoxyethanol is metabolized in animals by the enzyme alcohol dehydrogenase.[16] Blood or urine concentrations of 2-butoxyethanol or its major toxic metabolite, 2-butoxyacetic acid, may be measured using chromatographic techniques to monitor worker exposure or to confirm a diagnosis of poisoning in hospitalized patients. A biological exposure index of 200 mg 2-butoxyacetic acid per g creatinine has been established in an end-of-shift urine specimen for exposed U.S. employees.[17][18] 2-Butoxyethanol and its metabolites fall to undetectable levels in urine after about 30 hours in human males.[16]

Animal studies[edit]

Harmful effects have been observed in animals exposed to high levels of 2-butoxyethanol. Developmental effects were seen in a study by Ty et al. This study 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, there were statistically significant increases 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.[19]

Neurological effects have also been observed in animals exposed to 2-butoxyethanol. In a study by Dodd et al., Fischer 344 rats were exposed to 2-butoxyethanol at concentrations of 523 ppm and 867 ppm. Both female and male rats experienced decreased coordination after this exposure. Similarly, in a study by Dow et al., male rabbits showed a loss of coordination and equilibrium after exposure to 400 ppm of 2-butoxyethanol for two days.[20]

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.[19]

Regulation in Canada[edit]

2-Butoxyethanol has come under scrutiny in Canada, and Environment and Health Canada recommended that it be added to Schedule 1 of the Canadian Environmental Protection Act, 1999 (CEPA).[21] 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.[22]

Regulation in the US[edit]

2-Butoxyethanol is listed in the U.S. state of California as a hazardous substance,[23] and U.S. Employers are required to inform employees when they are working with it.[24]

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".[7] After it was deleted 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.[25][26] The safety of products containing 2-Butoxyethanol as normally used is defended by the industry trade groups the American Chemistry Council[26] and the Soap and Detergent Association.

References[edit]

  1. ^ a b Harris O., et al (August 1998). Toxicological Profile for 2-Butoxyethanol and 2-butoxyethanol acetate. U.S. Dept of Health and Human Services. 
  2. ^ a b Siegfried Rebsdat, Dieter Mayer "Ethylene Oxide" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005.doi:10.1002/14356007.a10_117.
  3. ^ a b c d e f g "Ethylene Glycol Mono-N-Butyl Ether". National Library of Medicine. Retrieved 2014-03-26. 
  4. ^ Elskamp, Carl J. "2-Butoxyethanol (Butyl Cellosolve) & 2-Butoxyethyl Acetate (Butyl Cellosolve Acetate)". United States Department of Labor. 
  5. ^ Jane Kay (2007-07-24). "Hazard warning on home cleaners: Study says many use chemicals linked to fertility problems". San Francisco Chronicle. Archived from the original on 28 February 2008. Retrieved 23 February 2008. 
  6. ^ Alexandra Gorman. "Potential Hazards of Home Cleaning Products". Women's Voices for the Earth. Retrieved 24 July 2007. 
  7. ^ a b c d Dickey, Robert; W. Dickhoff. "Assessment of the potential impact of COREXIT® oil dispersants on seafood safety". Dispersants and Seafood Safety. Retrieved 2014-03-26. 
  8. ^ "SAFETY DATA SHEET - PRODUCT: COREXIT® EC9527A". Nalco Environmental Solutions LLC. 1 March 2012. Retrieved 30 April 2014. 
  9. ^ "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. Archived from the original on 28 May 2010. Retrieved 4 June 2010. 
  10. ^ "Air Foam HD Material Data Safety Sheet". Product Safety. AquaClear, Inc. Retrieved 4 June 2010. 
  11. ^ Gift, J. S. (2005). "U.S. EPA's IRIS assessment of 2-Butoxyethanol: the relationship of noncancer to cancer effects". Toxicol. Lett. 156: 163–178. 
  12. ^ "Chemical Sampling Information | 2-Butoxyethanol". Occupational Safety & Health Administration. 
  13. ^ Hullar, T.; Anastasio, C. Yields of hydrogen peroxide from the reaction of hydroxyl radical with organic compounds in solution and ice. Atmospheric Chemistry and Physics, 11, 7209.
  14. ^ Agency for Toxic Substances and Disease Registry ToxFAQs
  15. ^ "Fomepizole fails to prevent progression of acidosis in 2-butoxyethanol and ethanol coingestion". Clinical Toxicology 48 (6): 569–571. July 2010. doi:10.3109/15563650.2010.492350. 
  16. ^ a b c 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: 164–173. 
  17. ^ 2009 TLVs and BEIs, American Conference of Industrial Hygienists, Cincinnati, Ohio, 2009, p.101.
  18. ^ R. Baselt (2008). Disposition of Toxic Drugs and Chemicals in Man (8th edition ed.). Foster City, CA: Biomedical Publications. pp. 208–210. 
  19. ^ a b 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>
  20. ^ 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>
  21. ^ "Current Use Patterns in Canada, Toxicology Profiles of Alternatives, and the Feasibility of Performing an Exposure Assessment Survey". Environment Canada. Retrieved 15 February 2011. 
  22. ^ "Regulations Amending the 2-Butoxyethanol Regulations". Canada Gazette. Canadian Department of Public Works and Government Services. 23 April 2014. Retrieved 30 April 2014. 
  23. ^ "California Code of Regulations, Title 8, Section 339. The Hazardous Substances List". State of California Department of Labor Relations. Archived from the original on 5 May 2008. Retrieved 2008-04-21. 
  24. ^ "Glycol Ethers Fact Sheet". California Hazard Evaluation and Information Service. Retrieved 29 October 2007. 
  25. ^ "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. Retrieved 23 February 2008. 
  26. ^ a b "EGBE: A World of Solutions 2000". July 2000. Archived from the original on 3 October 2006. Retrieved 30 April 2014. 

External links[edit]