Fusel oils

Alcohol solutions, 3.3 Denatured alcohol, 3 Fermentation amyl alcohol Fusel oil, 

Alcohols are a class of organic compounds containing one or more hydroxyl groups (-OH) attached to a carbon atom that exists in one of four configurations  

Bonded to one other carbon atom, a primary alcohol. 

Bonded to two other carbon atoms, a secondary alcohol. 

Bonded to three carbon atoms, tertiary alcohols, such as /er/-amyl alcohol. 

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Isobutyl alcohol, isobutanol, 2-methyl-propanol, isopropyl carbinol, Me2CHCH20H. B.p. 108°C. Occurs in fusel-oil. Oxidized by potassium permanganate to 2-methyl-propanoic acid dehydrated by strong sulphuric acid to 2-methylpropene. 

CH3 [CHJb-COOH. M.p. 31 5"C, b.p. 268-270 C. A fatty acid, occurring in wool as the potassium salt, as esters in fusel oil, and as glycerides in cows and goats milk and coconut and palm oils. 

Isovaleric acid, Me2CHCH2COOH, is a colourless liquid with the unpleasant odour of valerian, b.p. 177 "C. Occurs in the roots of valerian and angelica together with an optically active form of methylethylethanoic acid. Prepared by oxidation of isoamyl alcohol. A mixture of acids similar to that obtained from valerian roots is prepared by oxidation of fusel oil. 

Since (A) does not contain any other functional group in addition to the formyl group, one may predict that suitable reaction conditions could be found for all conversions into (A). Many other alternative target molecules can, of course, be formulated. The reduction of (H), for example, may require introduction of a protecting group, e.g. acetal formation. The industrial synthesis of (A) is based upon the oxidation of (E) since 3-methylbutanol (isoamyl alcohol) is a cheap distillation product from alcoholic fermentation ( fusel oils ). The second step of our simple antithetic analysis — systematic disconnection — will now be exemplified with all target molecules of the scheme above. For the sake of brevity we shall omit the syn-thons and indicate only the reagents and reaction conditions. 

Three significant, commercial processes for the production of amyl alcohols include separation from fusel oils, chlorination of C-5 alkanes with subsequent hydrolysis to produce a mixture of seven of the eight isomers (Pennsalt) (91), and a low pressure 0x0 process, or hydroformylation, of C-4 olefins followed by hydrogenation of the resultant C-5 aldehydes. 

The 0x0 process is the principal one in practice today only minor quantities, mainly in Europe, are obtained from separation from fusel oil. 

Fusel Oils. The original source of amyl alcohols was from fusel oil which is a by-product of the ethyl alcohol fermentation industry. Refined amyl alcohol from this source, after chemical treatment and distillation, contains about 85% 3-methyl-1-butanol and about 15% 2-methyl-1-butanol, both primary amyl alcohols. Only minor quantities of amyl alcohol are suppHed from this source today. A German patent discloses a distillative separation process for recovering 3-methyl-1-butanol from fusel oil (93). 

Propyl alcohol [71-23-8J, 1-propanol, CH2CH2CH2OH, mol wt 60.09, is a clear, colorless liquid having a typical alcohol odor it is miscible ia water, ethyl ether, and alcohols. 1-Propanol occurs ia nature ia fusel oils and forms from fermentation and spoilage of vegetable matter (1). 

Mutation. For industrial appHcations, mutations are induced by x-rays, uv irradiation or chemicals (iiitrosoguanidine, EMS, MMS, etc). Mutant selections based on amino acid or nucleotide base analogue resistance or treatment with Nystatin or 2-deoxyglucose to select auxotrophs or temperature-sensitive mutations are easily carried out. Examples of useful mutants are strains of Candida membranefaciens, which produce L-threonine Hansenu/a anomala, which produces tryptophan or strains of Candida lipolytica that produce citric acid. An auxotrophic mutant of S. cerevisiae that requires leucine for growth has been produced for use in wine fermentations (see also Wine). This yeast produces only minimal quantities of isoamyl alcohol, a fusel oil fraction derived from leucine by the Ehrlich reaction (10,11). A mutant strain of bakers yeast with cold-sensitive metaboHsm shows increased stabiUty and has been marketed in Japan for use in doughs stored in the refrigerator (12). 

Feints. Feints are the third fraction of the distiUation cycle derived from the distiUation of low wines in a pot stiU. This scotch term is also used to describe the undesirable constituents of the wash that are removed during the distiUation of grain whiskey in a continuous patent stiU (Coffey). These are mostiy aldehydes and fusel oils. 

Fusel Oil. Fusel oil is an inclusive term for heavier, pungent tasting alcohols produced during fermentation. Fusel oils are composed of a mixture of / -propyl, isobutyl, and isoamyl alcohols. 

Higher alcohols may be present in distilled spirits and are referred to as fusel oils or by specific name. 

The most common chromatogram in the distilled spirits industry is the fusel oil content. This consists of / -propyl alcohol, isobutyl alcohol, and isoamyl alcohol. Other common peaks are ethyl acetate, acetaldehyde, and methanol. The gc columns may be steel, copper, or glass packed column or capillary columns. Additional analyses include deterrninations of esters, total acids, fixed acids, volatile acids, soHds or extracts (used to determine... 

Ethanol [64-17-5] M 46.1, b 78.3 , d 0.79360, d 0.78506, n 1.36139, pK 15.93. Usual impurities of fermentation alcohol are fusel oils (mainly higher alcohols, especially pentanols), aldehydes, esters, ketones and water. With synthetic alcohol, likely impurities are water, aldehydes, aliphatic esters, acetone and diethyl ether. Traces of benzene are present in ethanol that has been dehydrated by azeotropic distillation with benzene. Anhydrous ethanol is very hygroscopic. Water (down to 0.05%) can be detected by formation of a voluminous ppte when aluminium ethoxide in benzene is added to a test portion. Rectified... 

Chemical Designationis - Synonyms Fementation amyl alcohol Fusel oil Isobutylcarbinol Isopentyl alcohol 3-Methyl-l-butanol Potato-spirit oil Chemical Formula (CH3)2CHCH2CH20H. Observable Characteristics - Physical(asshipped) Liquid Color Colorless Odor. Mild odor alcoholic, non-residual. 

Methylated spirit contains, in addition to ethyl and methyl alcohols, water, fusel-oil, acetaldehyde, and acetone. It may be freed from aldehyde by boiling with a—3 per cent, solid caustic potash on the water-bath with an upright condenser for one hour, or if larger quantities are employed, a tin bottle is preferable, which is heated directly over a small flame (see Fig. 38). It is then distilled with the apparatus shown in Fig. 39. The bottle is here surmounted with a T-piece holding a thermometer. The distillation is stopped when most of the spirit has distilled and the thermometer indicates 80°. A further purification may be effected by adding a little powdered permanganate of potash and by a second distillation, but this is rarely necessary. The same method of purification may be applied to over-proof spirit, which will henceforth be called spirit as distinguished from the purified product or absolute alcohol. 

Commercial amyl alcohol is contained in fusel oil from fer mentation and consists mainly of isobutyl carbinol together with about 13 per cent, of secondary butyl carbinol, which renders the liquid optically active. It turns the plane of polarisation to the left (see p. 116). 

Entflockung, /. deflocculation, entfremden, t.t. estrange abandon conceal, entfuhren, t.t. carry off. enthiseln, t.t. remove fusel oil from, rectify, entgasen, t.t. extract gas from, degas, out-gas. 

Ganmgs-fShigkeit, /. fermentability. -fuselol, n. fusel oil. -gewerb(e), n. fermentation industry. 

In the manufacture of absolute alcohol by fermentation, the product is separated and purified using several stages of distillation. In the first stage, a mixture of 5 mol per cent ethanol in water, with traces of acetaldehyde and fusel oil, is concentrated to 50 mol per cent. The concentration of alcohol in the wastewater is reduced to less than 0.1 mol per cent. 

Fusel oil basically comprises a mixture of alcohols such as isopentanol and isobutanol. The synthesis of isopentyl stearate has been performed using both microwave irradiation and conventional heating under solvent-free conditions (Eq. 20) [73],... 

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