tert-Amyl alcohol (TAA), systematic name 2-methylbutan-2-ol (2M2B), is a branched pentanol.

Historically TAA has been used an anesthetic[3] and more recently it has also been used as a recreational drug similar to ethanol[4] because TAA is mostly a positive allosteric modulator for GABA A receptors[5][6] just like ethanol is.[7] This means that TAA causes calming effects within the central nervous system by interacting indirectly (allosterically) with GABA A receptors and enhances (positive effect) their activity.

TAA is a colorless liquid with a burning flavor[8] and a very unpleasant odor[9] which has been described as being similar to paraldehyde with a hint of camphor.[10] TAA can be produced via fermentation,[11] but it is primarily produced through other means.[3][12] TAA remains liquid at room temperature making it a useful alternative solvent to tert-butyl alcohol.

Production [ edit ]

Industrial [ edit ]

TAA is primarily produced by the hydration of 2-methyl-2-butene in the presence of an acidic catalyst.[12][3]

Natural occurrence [ edit ]

Fusel alcohols including TAA are grain fermentation byproducts and therefore trace amounts of TAA are present in many alcoholic beverages.[11] Trace levels of TAA have also been detected in various foods, including fried bacon,[13] cassava,[14] rooibos tea.[15]

History [ edit ]

Between about 1880 and 1950 TAA was used as an anesthetic with the contemporary name of amylene hydrate. In 1930's[16] TAA was mainly used as a solvent for tribromoethanol (TBE), forming Avertin at a 0.5:1 volume ratio of TAA to TBE. TAA was rarely used as a sole hypnotic because of the existence of more efficient drugs.[3] Avertin is a brand-name for now discontinued TAA and TBE solution made by Winthrop Laboratories.[16]

Tertiary alcohols like TAA generally can not be oxidised to aldehyde or carboxylic acid[17] metabolites which are often toxic (e.g. acetaldehyde and formic acid from ethanol and methanol).

However, like other tertiary alcohol based anesthetics (e.g. methylpentynol, ethchlorvynol) TAA was eventually superseded by safer and more effective agents.[citation needed] The use of TBE and TAA solution was also discontinued in humans in the late 1940s, as back then TBE was noted to be harmful for the liver just like chloroform, which was also used as an anesthetic at the time. TBE and TAA solution is still used as a short-acting anesthetic for laboratory mice and rats.[16]

Nowadays TAA has found use as a recreational drug.[4]

Use and effects [ edit ]

TAA produces euphoria, sedative, hypnotic, and anticonvulsant effects similar to ethanol through ingestion or inhalation.[18] When ingested, the effects of TAA may begin in about 30 minutes and can last up to 1–2 days.[19] 2–4 grams of TAA causes unconsciousness. About 100 g or 127 ml of ethanol induces similar level of unconsciousness.[20]

Overdose and toxicity [ edit ]

The smallest known dose of TAA that has killed a person is 30 ml.[19]

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 LD 50 in rats is 1 g/kg. The subcutaneous LD 50 in mice is 2.1 g/kg.[21]

Quick loss of consciousness, simultaneous respiratory and metabolic acidosis,[19] fast heartbeat, increased blood pressure, pupil constriction, coma, respiratory depression[22] and death may follow from an overdose. Somebody who has overdosed and suffers from respiratory depression may be kept alive by performing a tracheal intubation and then giving artificial respiration with pumps.[19]

Metabolism [ edit ]

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,[23] though older sources suggest TAA is excreted unchanged.[3]

TAA oxidises to 2-methyl-2,3-butanediol.

The use of TAA cannot be detected with general ethanol tests or other ordinary drug tests. Its use can be detected from a blood or a urine sample by using gas chromatography–mass spectrometry for up to 48 hours after consumption.[22]

See also [ edit ]