''tert''-Amyl alcohol

tert-Amyl alcohol
Names
Preferred IUPAC name
2-Methylbutan-2-ol
Other names
2-Methyl-2-butanol
tert-Amyl alcohol
t-Amylol
TAA
tert-Pentyl alcohol
2-Methyl-2-butyl alcohol
t-Pentylol
Amylene hydrate
Dimethylethylcarbinol
Identifiers
3D model (JSmol)
1361351
ChEBI
ChemSpider
ECHA InfoCard 100.000.827
EC Number 200-908-9
KEGG
MeSH tert-amyl+alcohol
RTECS number SC0175000
UNII
UN number 1105
Properties
C5H12O
Molar mass 88.15 g·mol−1
Appearance Colorless liquid
Odor Camphorous
Density 0.805 g/cm−3[1]
Melting point −9 °C; 16 °F; 264 K
Boiling point 101 to 103 °C; 214 to 217 °F; 374 to 376 K
120 g·dm−3
log P 1.095
Vapor pressure 1.6 kPa (at 20 °C)
-70.9·10−6 cm3/mol
1.405
Viscosity 4.4740 mPa·s (at 298.15 K)[1]
Thermochemistry
229.3 J K−1 mol−1
−380.0–−379.0 kJ mol−1
−3.3036–−3.3026 MJ mol−1
Hazards
Safety data sheet hazard.com
GHS pictograms
GHS signal word DANGER
H225, H315, H332, H335
P210, P261
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., gasoline) Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine 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
3
1
0
Flash point 19 °C (66 °F; 292 K)
437 °C (819 °F; 710 K)
Explosive limits 9%
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

tert-Amyl alcohol (TAA), systematic name: 2-methylbutan-2-ol (2M2B), is a branched pentanol used primarily as a pharmaceutical or pigment solvent. It remains liquid at room temperature making it a useful alternative to tert-butyl alcohol. It is a colorless liquid with a pungent odor of camphor. It is slightly soluble in water and miscibile organic solvents. Although it can be produced naturally, by the fermentation of ethanol, it is primarily produced synthetically via hydroformylation.

Production

Industrial

Like other oxo alcohols TAA is primarily produced via hydroformylation. The reaction of 2-methyl-2-butene with water in the presence of an acid catalyst yields TAA.[2][3]

Natural occurrence

Fusel alcohols including TAA are grain fermentation by-products and therefore trace amounts of TAA are present in many alcoholic beverages.[4] Trace levels of TAA have also been detected in various foodstuffs, including fried bacon, cassava,[5][6] rooibos tea[7] and fruits such as apple and pineapple.

Pharmacology

Between about 1880 and 1950, it was used as an anesthetic, with the contemporary name of amylene hydrate. It was mainly used as a solvent for tribromoethanol, forming "avertin fluid" at a 0.5 : 1 ratio of TAA to TBE. TAA was rarely used as a sole hypnotic because of the existence of more efficient drugs.[3]

Oxidation of TAA to 2-methyl-2,3-butanediol

Tertiary alcohols like TAA cannot be oxidised to aldehyde or carboxylic acid metabolites, which are often toxic; this makes them safer drugs than primary alcohols.[8] However, like other tertiary alcohol based anaesthetics (e.g. methylpentynol, ethchlorvynol) TAA was eventually superseded by safer and more effective agents.

TAA produces euphoria, sedative, hypnotic, and anticonvulsant effects similar to ethanol through ingestion or inhalation.[9] It is active in doses of 2,000–4,000 mg, making it 20 times more potent than ethanol.[10][11] Its hypnotic potency is between chloral hydrate and paraldehyde[12] and between benzodiazepines and ethanol.

In rats, TAA is primarily metabolized via glucuronidation, as well as by oxidation to 2-methyl-2,3-butanediol. It is likely that the same path is followed in humans,[13] though older sources suggest it is excreted unchanged.[3]

Overdose and toxicity

An overdose produces symptoms similar to alcohol poisoning and is a medical emergency due to the sedative/depressant properties which manifest in overdose as potentially lethal respiratory depression. The oral LD50 in rats is 1000 mg/kg. The subcutaneous LD50 in mice is 2100 mg/kg.[14]

See also

References

  1. 1 2 Lomte, S.B.; Bawa, M.J.; Lande, M.K.; Arbad, B.R. (2009). "Densities and Viscosities of Binary Liquid Mixtures of 2-Butanone with Branched Alcohols at (293.15 to 313.15) K". Journal of Chemical & Engineering Data. 54: 127. doi:10.1021/je800571y.
  2. ↑ Kirk-Othmer Encyclopedia of Chemical Technology. 4th ed. Volumes 1: New York, NY. John Wiley and Sons, 1991-Present., p. V2: 716. http://toxnet.nlm.nih.gov/cgi-bin/sis/search/a?dbs+hsdb:@term+@DOCNO+5005
  3. 1 2 3 Adriani, John (1962). The Chemistry and Physics of Anesthesia. Second Edition. Illinois: Thomas Books. pp. 273–274. ISBN 9780398000110.
  4. ↑ George Milbry Gould; Richard John Ernst Scott (1919). The Practitioner's Medical Dictionary: Containing All the Words and Phrases Generally Used in Medicine and the Allied Sciences, with Their Proper Pronunciation, Derivation, and Definition. P. Blakiston's. p. 50. Retrieved February 7, 2013.
  5. ↑ Dougan, J.; Robinson, J.M.; Sumar, S.; Howard, G.E.; Coursey, D.G. (1983). "Some flavouring constituents of cassava and of processed cassava products". Journal of the Science of Food and Agriculture. 34 (8): 874. doi:10.1002/jsfa.2740340816.
  6. ↑ Ho, C.T.; Lee, K.N.; Jin, Q.Z. (1983). "Isolation and identification of volatile flavor compounds in fried bacon". Journal of Agricultural and Food Chemistry. 31 (2): 336. doi:10.1021/jf00116a038.
  7. ↑ Habu, Tsutomu; Flath, Robert A.; Mon, T. Richard; Morton, Julia F. (1 March 1985). "Volatile components of Rooibos tea (Aspalathus linearis)". Journal of Agricultural and Food Chemistry. 33 (2): 249–254. doi:10.1021/jf00062a024.
  8. ↑ Carey, Francis. Organic Chemistry (4 ed.). ISBN 0072905018. Retrieved 2013-02-05.
  9. ↑ Robert A. Lewis (1998). Lewis' Dictionary of Toxicology. CRC Press. p. 45. ISBN 1-56670-223-2.
  10. ↑ Hans Brandenberger & Robert A.A. Maes, ed. (1997). Analytical Toxicology for Clinical, Forensic and Pharmaceutical Chemists. p. 401. ISBN 3-11-010731-7.
  11. ↑ D.W. Yandell; et al. (1888). "Amylene hydrate, a new hypnotic". The American Practitioner and News. Louisville KY: John P. Morton & Co. 5: 88–89.
  12. ↑ F.A. Castle & C. Rice (March 1888). "Amylene and amylene hydrate". The American Druggist. 17 (3): 58–59.
  13. ↑ Collins, A.S.; Sumner, S.C.; Borghoff, S.J.; Medinsky, M.A. (1999). "A physiological model for tert-amyl methyl ether and tert-amyl alcohol: Hypothesis testing of model structures". Toxicological Sciences. 49 (1): 15–28. PMID 10367338. doi:10.1093/toxsci/49.1.15.
  14. ↑ Soehring, K.; Frey, H.H.; Endres, G. (1955). "Relations between constitution and effect of tertiary alcohols". Arzneimittel-Forschung. 5 (4): 161–165. PMID 14389140.
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