( 619 ) 
(about a quarter of its volume) of ethyl cinnamate. Von Mruxr 2) 
has found the same ester in liquid storax. 
The isolation of the pure ester from Kentjoer oil is very difficult 
as it is accompanied by a few other products one of which is very 
indifferent and has nearly the same boiling point. An effort to isolate 
the ethyl cinnamate (m.p. 12°) by cooling failed, for when placed 
in ice nearly the whole of the mass congealed which is no matter 
for astonishment, as it afterwards appeared that the indifferent admix- 
ture melts at 10°. 
If the fraction boiling at 155°—165° (at 30 m.m.) is treated 
with 80 percent alcohol, this dissolves the ester while the other 
compound floats on the alcoholic solution. By repeating this treat- 
ment a few times, I succeeded in obtaining an already fairly pure 
ester which was still further purified by partial freezing. A quantita- 
tive saponification and an elementary analysis showed, however, that 
it was still contaminated with a compound richer in carbon and 
hydrogen which also somewhat decreased the specific gravity. The 
odour and the boiling point, however, were the same as those of a 
specially prepared specimen of ethyl cinnamate. The compound 
readily absorbed bromine but before the required amount has been 
taken up the liquid assumes a splendid violet colour?) which on 
further addition of bromine becomes green. 
The portion of the essential oil insoluble in alcohol which also 
turns violet with bromine was freed from small quantities of ethyl 
cinnamate by heating with alcoholic potassium hydroxide which 
became dark coloured and, consequently, the treatment was repeated 
a few times. After distillation of the purified oil a colourless liquid 
was obtained which turned the plane of polarisation 7° to the left, 
when using a tube of 200 m.m. Placed in ice, it solidified to 
leaf-shaped crystals melting at about 8° which, however occluded 
some liquid product. By draining the crystals and remelting them 
a liquid was obtained which turned only — 5.5°. The further 
purification would not have given much trouble on a cold winter 
day in Europe but in the vapour-saturated air of the tropical climate 
it has taken much patience and labour to finally obtain by the 
freezing process a liquid which only feebly turned the plane of 
polarisation and hardly turned green with bromine. To obtain it 
still purer it was treated with a solution of bromine in chloroform 
1) Ann. d. Chemie 188, 202; van Irauuir, Ned. Tijdschr. v. Pharm. 13, 103. 
*) This reaction reminds of that for myrrh. 
