What is "amyl alcohol"

Alcohol \Al"co*hol\ ([a^]l"k[-o]*h[o^]l), n. [Cf. F. alcool, formerly written alcohol, Sp. alcohol alcohol, antimony, galena, OSp. alcofol; all fr. Ar. al-kohl a powder of antimony or galena, to paint the eyebrows with. The name was afterwards applied, on account of the fineness of this powder, to highly rectified spirits, a signification unknown in Arabia. The Sp. word has both meanings. Cf. Alquifou.]

1. An impalpable powder. [Obs.]

2. The fluid essence or pure spirit obtained by distillation. [Obs.]
   --Boyle.

3. Pure spirit of wine; pure or highly rectified spirit (called also ethyl alcohol or ethanol, CH3.CH2.OH); the spirituous or intoxicating element of fermented or distilled liquors, or more loosely a liquid containing it in considerable quantity. It is extracted by simple distillation from various vegetable juices and infusions of a saccharine nature, which have undergone vinous fermentation.

   Note: [The ferementation is usually carried out by addition of brewer's yeast, Saccharomyces cerevisiae to an aqueous solution containing carbohydrates.]

   Note: As used in the U. S. ``Pharmacop[oe]ia,'' alcohol contains 91 per cent by weight of ethyl alcohol and 9 per cent of water; and diluted alcohol (proof spirit) contains 45.5 per cent by weight of ethyl alcohol and 5

4. 5 per cent of water.

   4. (Organic Chem.) A class of compounds analogous to vinic alcohol in constitution. Chemically speaking, they are hydroxides of certain organic radicals; as, the radical ethyl forms common or ethyl alcohol ( C2H

5. OH); methyl forms methyl alcohol ( CH3.OH) or wood spirit; amyl forms amyl alcohol ( C5H11.OH) or fusel oil, etc.

n. (context organic compound English) Any of the isomers of pentanol, C₅H₁₁OH; the principal constituent of fusel oil.

n. a mixture of 2 or more isomeric alcohols; used as a solvent and in organic synthesis

An amyl alcohol is any of 8 alcohols with the formula CHOH. A mixture of amyl alcohols (also called amyl alcohol) can be obtained from fusel alcohol. Amyl alcohol is used as a solvent and in esterfication, by which is produced amyl acetate and other important products. The name amyl alcohol without further specification applies to the normal (straight-chain) form, 1-pentanol.

These are the 8 structural isomers of alcohols with molecular formula CHO:

:{| class="wikitable sortable" |+Amyl alcohol isomers |- ! Common Name !! Structure !! Type !! IUPAC Name !! Boiling point (°C) |- | normal amyl alcohol | | primary | Pentan-1-ol | 138.5 |- | isobutyl carbinol
or isoamyl alcohol
or isopentyl alcohol
or isoprenol | | primary | 3-Methylbutan-1-ol | 131.2 |- | active amyl alcohol | | primary | 2-Methylbutan-1-ol | 128.7 |- | tertiary butyl carbinol
or neopentyl alcohol | | primary | 2,2-Dimethylpropan-1-ol | 113.1 |- | 3-Pentanol | | secondary | Pentan-3-ol | 115.3 |- | methyl (n) propyl carbinol | | secondary | Pentan-2-ol | 118.8 |- | methyl isopropyl carbinol | | secondary | 3-Methylbutan-2-ol | 113.6 |- | dimethyl ethyl carbinol
or tertiary amyl alcohol | | tertiary | 2-Methylbutan-2-ol | 102 |}

Three of these alcohols, active amyl alcohol (2-methylbutan-1-ol), methyl (n) propyl carbinol (pentan-2-ol), and methyl isopropyl carbinol (3-methylbutan-2-ol), contain an asymmetric carbon atom and are therefore optically active.

The most important is isobutyl carbinol, the chief constituent of fermentation amyl alcohol and a constituent of fusel oil. It can be separated from fusel oil by either of two methods: shaking with strong brine solution and separating the oily layer from the brine layer; distilling it and collecting the fraction that boils between 125 and 140 °C.

Further purification is possible with this procedure: shaking the product with hot limewater, separating the oily layer, drying the product with calcium chloride, and distilling it, collecting the fraction boiling between 128 and 132 °C.

Isobutyl carbinol can be synthesized from isobutanol by conversion into isovaleraldehyde, which is subsequently reduced to isobutyl carbinol by means of sodium amalgam. It is a colourless liquid of density 0.8247 g/cm³ (0 °C), boiling at 131.6 °C, slightly soluble in water, and easily dissolved in organic solvents. It has a characteristic strong smell and a sharp burning taste. Amyl alcohol has an oral LD50 of 200 mg/kg in mice, suggesting that it is significantly more toxic than ethanol. On passing the vapour through a red-hot tube, it decomposes into acetylene, ethylene, propylene, and other compounds. It is oxidized by chromic acid to isovaleraldehyde, and it forms addition compounds crystals with calcium chloride and tin(IV) chloride.

The other amyl alcohols may be obtained synthetically. Of these, tertiary butyl carbinol has been the most difficult to obtain, with the first reported synthesis in 1891 by L. Tissier using the reduction of a mixture of trimethyl acetic acid and trimethylacetyl chloride with sodium amalgam. It is a solid that melts at 48 to 50 °C and boils at 112.3 °C.