AMYL ESTEE OF EUDESMIC ACID IN EUCALYPTUS OILS. 79 



Determination of the Bromide. 



On adding bromide water to the aqueous solution of the acid it 

 it was at once bleached ; the acid is, therefore unsaturated. The 

 acid was dissolved in hot water and bromine added until in excess. 

 The bromide was very soluble in hot water, on cooling and stand- 

 ing a crystalline mass was obtained, this was almost colourless, it 

 melted at 102° - 103° C. The determination of this bromide was 

 made by ignition with lime in the usual way. 0*1576 gramme 

 bromide taken, total silver bromide obtained 0*1546 gramme or 

 0*0658 gramme bromine, equivalent to 41*75 per cent, bromine. 

 C 14 H 18 Br 2 2 requires 42*6 per cent, bromine. This indicates a 

 dibromide. The reactions showed the bromine to be present in 

 the side chain. 



Molecular value of the acid. 



On adding silver nitrate to the cold aqueous solution of the acid 

 no precipitate was obtained, the silver salt being soluble in dilute 

 aqueous solution. The method adopted was to add a little water 

 to some of the pure acid crystals, and then just sufficient ammonia 

 to dissolve the acid. On adding two or three drops of silver 

 nitrate solution a curdy precipitate formed at once, the solution 

 was removed from this and silver nitrate added in excess ; fine 

 crystallisation rapidly took place, this was finally crystallised from 

 water. The silver salt is exceedingly soluble in hot water and 

 is fairly soluble in cold water. 0*0762 gramme of the silver salt 

 gave 0*0258 gramme metallic silver on ignition, equivalent to 

 33*86 per cent.; the molecular weight of the acid from this deter- 

 mination is 212. 0*0204 gramme silver salt gave 0*0068 gramme 

 silver, equivalent to 33*33 per cent., molecular weight of acid from 

 this is 217. 



An acid with a formula C 14 H 18 2 has a molecular weight 218, 

 and 13 H 17 COOAg contains 33*23 per cent, silver. 



Action of Nitric Acid. 

 On treating the acid crystals with nitric acid they at once 

 dissolved with formation of a crimson colour, this soon changed 

 to orange, on heating it became almost colourless. On adding 



