EUCALYPTUS OIL CONTAINING GERANYL ACETATE. 147 



Eucalyptus oils, determined during the research, are absent, viz., 

 the amyl ester of eudesmic acid present in largest amount in the 

 oil of E. aggregata; the iso-valeric acid ester present in greatest 

 amount in the oil of E. saligna, and the acetic acid ester present 

 in the oil of an Eucalyptus sp. at present undetermined. It is 

 thus probable that this method might be used quantitatively for 

 the determination of geranyl acetate occurring in other essential 

 oils together with other esters. 



Determination of the free alcohol. 



The acetylation of the free alcohol in the oil was performed by 



gently boiling for one and a half hours with acetic anhydride and 



anhydrous sodium acetate, decomposing the remaining anhydride 



with water and washing the oil until the water ceased to react acid. 



1-5066 grammes of this oil required -3164 gramme potash ; 

 saponification figure =210 

 equal to 73*5 per cent, geranyl acetate. As 60*34 per cent, 

 existed as ester in the original oil we have 13-16 percent, of ester 

 formed from the free alcohol present. The free geraniol in the 

 oil was thus 10-64 per cent. 



Determination of the acid of the ester. 

 The aqueous portion after saponifying the oil was evaporated 

 to small bulk and distilled with sulphuric acid, adding water until 

 it ceased to distil acid. The distillate gave the reactions for acetic 

 acid. A portion of the distillate was exactly neutralised with 

 barium hydrate, evaporated to dryness, heated to render the salt 

 anhydrous, and ignited with sulphuric acid. 0-828 gramme gave 

 0-754 gramme barium sulphate = 91-06 per cent. A second deter- 

 mination gave identical results. Barium acetate requires 91 37 

 per cent, of barium sulphate, so that but a minute quantity of a 

 higher volatile acid than acetic acid can be present. An odour 

 of valeric acid was at first detected and it may be that it had been 

 derived by oxidation of the trace of valeraldehyde detected when 

 distilling the oil. It is not likely to be present as free acid, 

 because the free acid present in Eucalyptus oils is entirely acetic 



