Biological Chemistry. 



in distilleries by various forms of stills. The fusel oil is a 

 mixture which can, by fractional distillation, be separated 

 into various components, amongst which is propyl alcohol. 

 Amyl Alcohols (C 5 H 12 0). Of the eight isomerides which 

 are capable of existence, two occur in fusel oil. These are 



known to be 'isobutyl carbinol, ^ 3N >CH - CH 2 CH 2 OH, 



Otlg/ 



and the so-called active amyl alcohol, which has the con- 

 stitution no . ^NCH CH 2 OH. The ordinary com- 



mercial amyl alcohol, which is largely employed as solvent, 

 possesses a characteristic pungent smell. 



THE POLYHYDROXY ALCOHOLS. 



In addition to those substances containing one hydroxyl 

 group, others are known which contain two or more such 

 groups, which may be regarded as derived from hydro- 

 carbons by the substitution of two or more hydrogen 

 atoms. Just as from a mono-halogen substitution product 

 of a hydrocarbon, by the treatment with aqueous solutions 

 of caustic alkalis, a monohydroxy alcohol can be obtained, 

 so from the poly-substituted halogen derivatives, poly- 

 hydroxy alcohols can be produced. Thus from ethylene 



CH 2 Br CH 2 OH 



dibromide | an alcohol | can be formed. 



CH 2 Br CH 2 OH 



The dihydroxy derivatives are known as the glycols. 



CH 2 OH 

 Ethylene glycol, or simply glycol, | is a thick 



CH 2 OH 



colourless liquid of sweetish taste and boiling point 197*5, 



CH 2 ONa CH 2 ONa 

 from which two sodium derivatives | and | 



CH,,OH CH.ONa 



