Chemistry of Essential Oils

428 THE CHEMISTEY OF ESSENTIAL OILS

The principal constituent of this oil is d-limonene. Dipentene is

also present. Methyl anthranilate and methyl methyl-anthranilate are

ulso present, and traces of an unknown aldehyde.

The determination of the anthranilic acid esters is of importance in

the essential oils of this group which contain it. The only method of

any value is that of Hesse and Zeitschel,^1 which is as follows:—

About 25 grams of the oil are dissolved in two to three times this

quantity of dry ether and the solution cooled to 0° in a freezing mixture,

and a mixture of 1 volume of sulphuric acid in 5 volumes of ether added

drop by drop until no further precipitation takes place. The precipitate

is collected in a filter and washed with dry ether. The compound of the

ester with sulphuric acid is then dissolved in water, and titrated with

semi-normal alkali, using methyl orange as indicator. If S grams of

oil be used, and A c.c. of semi-normal alkali be required for the titration,

then the percentage oihnethyl anthranilate is

A x 3-775

OIL OF NEKOLI.

This oil is distilled from the fresh flowers of the bitter and the
sweet orange. The former, which is the more valuable, is known as
" Oil of Neroli, Bigarade " (which is ordinary neroli oil), the latter as
"Oil of Neroli, Portugal". The greater part of the neroli oil of com-
merce is distilled in the south of France, one of the chief centres being
Vallauris. The yield of oil varies greatly according to the time of the
season when the flowers are collected. The gathering of the flowers
commences about the last week in April and continues till the last week
in May, or possibly a little later. The early gathered flowers yield about
half a gram of oil per kilo, whilst those gathered late in May yield
double this quantity. The petals are separated from the sepals and
covered with water in the still, and the contents heated by means of coils
of superheated steam. The oil coming over is separated, and the water
is sold as orange flower water.
There are numerous orange gardens in Spain, Algeria, Sicily, Greece,
and Turkey in Asia, but only a small amount of oil is distilled in these
countries. A small quantity of oil, which is equal in perfume value to
the oil distilled in France, is prepared in Tunis and Algeria, the principal
Tunisian centre being the district of Nabeul, where about 60,000 kilos
of flowers are dealt with annually. The distillation is in the hands
of Arabs, many of whom use small stills which take only 3 kilos of
flowers.
The neroli oil industry is also being well developed in Malaga.
From the port of Malaga northward along the Biver Guadalhorce
right up to Alora, a distance of 50 kilometres, the flowers are grown in
great profusion. On some days as much as 6500 kilograms of flowers
are dealt with at the distillery established at Alora. Needless to say,
however great the arrival of blossom it must be dealt with immediately.
In the photograph reproduced^2 one of the series of stills used at
Alora for this work is illustrated. It takes a charge of from 400 to 450
kilos of flowers.

(^1) Berichte, 34 (1901), 296. (^2) From P. and E.O.R. (1913), 137.