Amyl alcohol, active

Later we measured the concentrations of n-propyl, isobutyl, and the combined isoamyl and active amyl alcohols (3-methyl-l-butyl alcohol and 2-methyl-l-butyl alcohol) in distillation tray liquids using a gas chromatographic method with n-butyl alcohol as the internal standard. The distribution of the higher alcohols in the 14-tray concentrating section of a 12-inch pilot column during a run in which the product from tray 7 was 169° proof is shown in the upper portion of Figure 4. The... 

Pentene-2 has been prepared 1 by treating the iodide made from diethylcarbinol with alcoholic potash, by dehydrating active amyl alcohol by means of fused zinc chloride,2 and from 3-bromo-pentane and alcoholic potash.3... 

Theory of van t Hoff-LeBel.—Two men independently of each other advanced a theory which explains these facts. One, a Dutch chemist by the name of van t Hoff, and the other a French chemist, LeBel. On examining the structural formulas of optically active compounds these men each saw that they differed in a common way from all optically inactive compounds which were not possible of being split into optical components. Taking as an illustration the alcohol with which we are dealing, viz., active amyl alcohol or 2-methyl butanol-1 we see by examining its formula that one of the carbon atoms is characteristically different from all of the others. 

In the case of tartaric acid, which we shall study later, we have to consider two such carbon atoms directly united to each other by one of the bonds, and we shall find that the theory applies as truly here as in the first case given of the active amyl alcohols. 

The existence of three stereo-isomeric lactic acids is therefore explained in exactly the same way as the three stereo-isomers in the case of active amyl alcohol, 2-methyl butanol-1 (p. 90). We need not repeat the discussion of stereo-isomerism as explained by the van tHoff-LeBel theory of the asymmetric carbon atom, i.e., the tetra-hedral theory. The discussion as previously given for the amyl alcohols, applies exactly in the present case. 

Amyl alcohols occur in eight isomeric forms and have the empirical formula CjHnOH. All are liquids at ambient conditions except 2,2-dimethylpropanol (neopentyl alcohol), which is a solid. Almost all amyl alcohols are manufactured in the United States by the hydroformylation of butylenes. Yeast fermentation processes for ethanol yield small amounts of 4-methyl-l-butanol (isoamyl alcohol) and 2-methyl-1-butanol (active amyl alcohol, scc-butyl-carbinol) as fusel oil. However, when the amino acids leucine and isoleucine are added to sugar fermentations by yeast, 87% and 80% yields of 4-methyl-l-butanol and 2-methyl-l-butanol, respectively, are obtained (Fieser and Fieser, 1950). These reactions are not suitable for commercial applications because of cost, but they do indicate the close structural relationship between these C5 amino acids and the C5 alcohols. The reactions occur under nitrogen-deficient conditions. If a nitrogen source is readily available, the production of the alcohols is lowered considerably. 

When starch is the starting material, there is obtained, in addition to ethyl alcohol, a smaller amount of fusel oil (German Fusel, inferior liquor), a mixture of primary alcohols mostly isopentyl alcohol with smaller amounts of /2-propyl alcohol, isobutyl alcohol, and 2-methyl-1-butanol, known as active amyl alcohol amyl pentyl). 

Problem 15.5 The isopentyl and active amyl alcohols are formed by enzymatic transformation of the amino acids leucine and isoleucine, which come from hydrolysis of protdn material in the starch. 

For example, active amyl alcohol with an asymmetric carbon atom can have only the formula. 

Amylic Group, The active amyl alcohol has the formula ... 

Figure 2. Effect of split ratio on the resolution of isoamyl and active amyl alcohol in hexane. Column, 6 m x 50 um DB-1, df 0.2 um 40°C isothermal hydrogen carrier at 43.5 cm/sec (51.3 uL/min).

Fusel Oil and Succinic Acid, etc.—It has been shown that this group of by-products derives not from the sugar but from other materials present in the fermenting liquor. F. Ehrlich in many researches (1904-1910) has shown that the higher alcohols and aldehydes, which when mixed we call fusel oil, are formed by the deammination of amino acids resulting from the hydrolysis of proteins. Thus isoamyl alcohol, which is the chief constituent of fusel oil, is closely related to leucine, amino-isohexoic acid, and active amyl alcohol is similarly related to isoleucine, a-amino-/ -... 

Beilstein Handbook Reference) Active amyl alcohol Active primaiy amyl alcohol AI3-24190 BRN 1718810 sec-Butylcarbinol dl-sec-Butyl carbinol EINECS 205-289-9 EINECS 252-1634 HSDB 5626 NSC 8431 Primary active amyl alcohol. Liquid bp = 128" d = 0.8150 slightly soluble in H2O, very soluble... 

Fusel oil is another product which usually occurs in alcoholic fermentation of sugar and persists in traces even in alcohol after rectification. Fusel oil is mainly inactive amyl alcohol ((CHe), .CH.CH,.CH, (OH)) but is always accompanied by active amyl alcohol. 

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