EUTACE^E 433
Koure-Bertrand Filsl state that certain constituents of neroli oil are
destroyed by steam distillation in the ordinary method. They state that
slight modification in the distillation process produces distinct alterations
in the physical characters of the oil, especially the optical rotation. They
have therefore carried out an exhaustive examination of neroli oil made
by an extraction process, with subsequent distillation.
For this purpose they treated in May
and at the end of October about 300 kilos
of flowers.
The flowers were extracted by three
washings with petroleum spirit. The
three solutions were united, dried, and
filtered, then the solvent was distilled off,
care being taken to expel the last traces
in vacuo. The residue from this distilla-
tion is a brown, viscous mass composed
of vegetable wax, the colouring matter
and the essential oil of the flower.
This brown residue was then sub-
jected to distillation in a current of steam.
In a suitable rectifying apparatus the es-
sential oil alone is carried over, free from any waxy matters. The water
condensed in the course of this operation is exhausted with ether, after
saturation with common salt, and the evaporation of the ether leaves a
residue which is termed the soluble essential \ oil. The portion which
floats on the surface of the condensed water and which is isolated by
simple decantation is termed the direct essential oil; the name of total
essential oil is given to that which is obtained by mixing the two former
oils in proportion to their yields.
The characters of the essential oils so obtained are set out in the.
following tables:—
Fio. 44.—Arabian still in Tunisia
(native distillation of neroli oil).
[I'(a) Direct Essential Oils.May.Density at 15° C 0* 8883
Index of Refraction nd^15 1 1-474
Rotatory Power....- 0° 40'
Solubility in 80 per Cent. Alcohol... I 1 vol. and over
Acid Value...... 0*7
Coefficient of Saponification.... | 71'4
Total Esters (as Linalyl Acetate)... | 25*0 per cent.
Coefficient of Saponification of the Acetylated |
Oil 172-2
Total Alcohol (as Linalol).... 54'4 per cent.
Methyl Anthranilate , 2'43 „Autumn.0-8866
1-469- 4° 98'
1 vol. and over
0-7
96-6
33-8 per cent.
185-9
59-3 per cent.
1-57 „VOL. I(^1) Bulletin, April, 1910, 43.
28