458 THE CHEMISTEY OF ESSENTIAL OILS
fact that its composition by combustion is equivalent to C 10 H 16 , all form
a very strong presumption that the olefine-terpene myrcene has here
been isolated, and that it in fact almost entirely constitutes the first 50 per
cent, of the oil; although it is much more prone to polymerization and
oxidation than when similarly obtained from bay oil. In the higher
fractions evidence was obtained of the presence of the allied alcohol
myrcenol and its acetate; also of methyl chavicol, anethol, and chavicol
or similar phenol, with sesquiterpenes.
No indications whatever of diosphenol were observed.
The oil of Barosma venusta has recently been examined by Goulding
and Eoberts.
1
The oil examined had the following characters:—
Specific gravity (15°) 0-865
Optical rotation + 0° 47'
Acid value 56
Ester ,, ... 6-2
Corresponding with 2'2 per cent, of esters.
Ester value after acetylation ....... 55
Corresponding with 157 per cent, of total alcohols, or 14-3 per cent.. of free
alcohols and 2*2 per cent, of esters.
On distillation, under atmospheric pressure, some decomposition oc-
curred, but when distilled under 60 mm. pressure a hydrocarbon having
the properties of myrcene was obtained, showing a great tendency to
resinify and combining with four atoms of bromine.
A small proportion of aldehyde was separated by shaking the oil with
solution of sodium hydrogen sulphite, separating and washing with ether
and extracting the aqueous solution with ether, after making alkaline
with sodium hydroxide. The aldehyde was identified as anisic aldehyde,
being readily converted into anisic acid melting at 183° to 184°. The
presence of linalol was confirmed in the fraction boiling at 190° to 205°
by oxidation to citral. No diosphenol was obtained, and only 02 per
cent, of phenol was absorbed by solution of sodium hydroxide after wash-
ing with sodium carbonate solution and sodium bisulphite solution to
remove acids and aldehydes. The small quantity of phenol extracted
gave no coloration with ferric chloride. Methyl chavicol was identified
in the fraction boiling at 213° to 218° by conversion into anethol, melting
at 22°, and confirmed by determination of the methoxyl group.
The residual fraction contained sesquiterpenes together with poly-
merides and decomposition products of myrcene.
The approximate composition of the oil is as follows :—
Percent.
Hydrocarbons, chiefly or entirely myrcene.... 430
Aldehydes, chiefly or entirely anisaldehyde
Phenols
Phenol ethers (methyl chavicol).
Alcohols partly linalol 1 4 ' 3
Esters calculated as C 10 H 17 O. Ac 2
Sesquiterpenes loss, etc. (by difference)
0*5
0'2
21*4
14'3
2-2
18'4
The only important difference from the results of Jensen's investiga-
tion is the almost complete absence of phenols, which occurred in Jensen's
oil to the extent of 16 per cent., and gave a dark green coloration with
ferric chloride. This was presumed to be impure chavicol, although not
definitely proved. It should be pointed out, however, that Jensen's oil
1
Jour. Chem. Soc. Trans. (1914), 2618.