Fusel Oil Composition

Thanks to Brad, heres a bit more detail on what has been found in the fusels, and can be present in your distilled product:

Quotes from the MERCK INDEX 10th Ed. 1983 (entry number given):

4195. Fusel Oil.

A by-product of carbohydrate fermentation to produce ethyl alc. The material varies widely in composition, depending on the fermentation raw material used, but contains chiefly isopentyl alcohol and 2-methyl-1-butanol as well as isobutyl alcohol(20%), n-propyl alcohol(3-5%), and small amounts of other alcohols, esters and aldehydes. Described as an oily liq with a disagreeable odor; 60% boils at 122-138°. Amyl alcohol (commercial) obtained by chemical treatment and refining of fusel oil contains about 85% isopentyl alcohol and 15% 2-methyl-1-butanol. Ref: Industrial Chemicals, W.L. Faith et al.

5816. Methanol.

Methyl alcohol; carbinol; wood spirit; wood alcohol. Flammable, poisonous, mobile liq. Slight alcoholic odor when pure; crude material may have a repulsive, pungent odor. Burns with a non-luminous, bluish flame. bp 64.7°. mp -97.8°. Caution: Poisoning may occur from ingestion, inhalation or percutaneous absorption. Acute Effects: Headache, fatigue, nausea, visual impairment or complete blindness (may be permanent), acidosis, convulsions, mydriasis, circulatory collapse, respiratory failure, death. Death from ingestion of less than 30ml has been reported. Usual fatal dose 100-250ml. Chronic: Visual impairment, cf.Patty's Industrial Hygiene and Toxicology vol. 2C, G.D.Clayton et al. pp 4528-4541.
The alcohols of interest in the same MERCK: (just the boiling points at atmospheric pressure, some basic characteristics and all the alternative names for each alcohol)

212. Alcohol, Anhydrous. Ethanol

; ethyl alcohol. Clear, colorless, very mobile, flammable liquid; pleasant odor; burning taste. Absorbs water rapidly from air. bp 78.5°. mp -114.1°. Solidif below -130°.

4978. Isobutyl Alcohol.

2-methyl-1-propanol; isopropylcarbinol; 1-hydroxymethylpropane; fermentation butyl alcohol. Colorless, refractive liq; flammable; odor like that of amyl alcohol, but weaker. bp 108°. mp -108°.

5042. Isopentyl Alcohol.

3-methyl-1-butanol; isoamyl alcohol; isobutyl carbinol; primary isoamyl alcohol; fermentation amyl alcohol. Liquid; characteristic, disagreeable odor; pungent, repulsive taste. Vapors are poisonous! bp 132.0°. mp -117.2°. Caution: May be moderately irritating to mucous membranes. High concns may cause CNS depression, narcosis; lower concns, headache, dizziness.

5906. 2-Methyl-1-butanol.

Active amyl alcohol; dl-sec-butyl carbinol. One of the major components of fusel oil. Liquid, bp 128°.


dl-sec-Isoamyl alcohol; sec-isopentyl alcohol; isopropyl ethyl carbinol. Liquid, bp 113-114°. Fusel oil component.

211.Alcohol, 95%.

Binary azeotrope having a distillate composition of 95.57% ethyl alcohol (by wt) and bp 78.15°C. Also specified as containing 94.9% by vol or 92.3% by wt of ethyl alcohol at 15.56°C. See U.S.P. XVIII, 20, 1067(1970). d 0.816 at 15.56°C (60°F).

6985. 1-Pentanol.

Pentyl alcohol; n-amyl alcohol; n-butyl carbinol. Liquid, mild characteristic odor. bp 137.5°C. mp -79°C. Slightly soluble in water (2.7g/100ml at 22°C); misc with alcohol, ether. LD50 orally in rats: 3030mg/Kg, P.M.Jenner et al., Food Cosmet. Toxicol. 2, 327 (1964). Toxicity: Irritating to eyes, respiratory passages. Narcotic: E.Browning, Toxicity and Metabolism of Industrial Solvents (Elsevier, New York, 1965)pp 356-367.

6986. 2-Pentanol.

dl-sec-Amyl alcohol; methyl propyl carbinol. Liquid, characteristic odor. bp 119.3°C. Slightly soluble in water (16.6g/100ml at 20°C). Miscible with alcohol, ether. Caution: see 1-Pentanol.

6987. 3-Pentanol.

Diethyl carbinol. Liquid, characteristic odor. bp 115.6°C. Slightly soluble in water (5.5g/100g at 30°C); sol in alcohol, ether. LD50 orally in rats: 1870mg/Kg, Smyth et al., Arch. Ind. Hyg. Occup. Med. 10, 61 (1954). Caution: see 1-Pentanol.

Brad also commented :

As you can probably see from these brief descriptions, methanol appears to be one of the most toxic of all. In fact the other alcohols by and large appear to have much the same effct as ethanol when consumed (with much greater activity/toxicity), except methanol which has some toxic metabolite (formaldehyde) which is somehow toxic to the optical nerves of the eye. Ethanol administration is actually used to slow down the metabolism of methanol when it's accidentally consumed!! Note the Merck note about Chronic effect (long-term use) of methanol being visual impairment; does this occur to heavy drinkers?!?

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