202 



These figures seemed fair in the cases of propyl and isobutyl alcohols, but poor for 

 amyl alcohol. They apparently indicate the complete destruction of a portion of the 

 latter at some stage of the process. Varying the amount of alkali made no improve- 

 ment. 



That the results were slightly high, as in the case of the propyl and isobutyl alcohols, 

 might be expected, for permanganic acid and manganese dioxid are produced on 

 acidifying and are present together for several minutes during reduction by oxalic 

 acid. The excessive destruction of permanganate .with amyl alcohol points to other 

 causes. 



As oxalic acid acts very slowly in reducing the manganese dioxid, it was decided 

 to substitute hydrogen peroxid. Sulphuric acid was added to hydrogen peroxid and 

 the mixture resulting from the oxidizatica was poured slowly into it. This gives the 

 permanganate little opportunity to react with free organic acids, as it is reduced by 

 the hydrogen peroxid as it is acidified. 



Determination of amyl alcohol, substituting hydrogen peroxid for oxalic acid. 



A series was run in which isobutyl and propyl alcohols were used instead of amyl 

 alcohol. 



Determination of isobutyl and propyl alcohols, substituting hydrogen peroxid for oxalic acid. 



The results indicate incompletion of the oxidation at 0, so the procedure was 

 adopted of starting the oxidation at and allowing the mixture to warm slowly to 

 room temperature. The mixture was allowed to remain ten minutes in the ice bath 

 and taken out and warmed so that it reached room temperature (about 23 C.) in twenty 

 minutes. The experiments reported below were conducted with propyl alcohol. 



Determination of propyl alcohol after warming solution to room temperature. 



