Essential Oil of Boronia pinnata, 19 



.although a satisfactory bromide was not obtained. At first the 

 bromine was absorbed without evolution of hydrobromic acid, but 

 later the evolution of HBr. was pronounced, the solution becom- 

 ing dark purple. 



Formation of the Acid. 



A portion was oxidised by Potassium permanganate in alkaline 

 solution ; considerable heat was evolved. After completion of the 

 reaction, the remaining colour was removed by sulphurous acid, 

 filtered, evaporated to small bulk, and acidified with dilute sul- 

 phuric acid. A solid acid separated at once. This w^as purified 

 from boiling water, from which it crystallised in needles. It 

 melted sharply at 169°C (corr.) without decomposition. The acid 

 was titrated with decinormal sodium hydroxide; 0.13 gram dis- 

 solved in absolute alcohol required 6.15 c.c. y^^ NaOH to neutralise, 

 thus 40 grams would neutralise 211.4 grams of acid,CioHi.205= 212. 



It was thus evident that the acid was trimethylgallic acid 

 C10H12O5, the characteristic acid formed by the oxidation of 

 elemicin. 



That a small quantity of iso-elemicin was also present was 

 indicated by the formation of a minute quantity of acetic acid on 

 oxidation by Potassium permanganate. This was shown by dis- 

 tilling over the free acid and forming with it the Barium salt. 

 This on ignition gave 91.6 per cent. BaSO^. Theory requires 91.37 

 per cent. 



The above investigation shows that the principal constituent in 

 the oil of Boronia pi7inata is the trimethoxyphenol-ether, Elemicin, 

 (4 allyl — 1,2,6 trimethoxy benzol) and that it occurs in the oil of 

 this species to the extent of about 70 per cent. 



3A 



