Chemistry of Essential Oils

BESEDACEJE 527

Boiling-point 178° to 179°
Specific gravity at 0° 0-922
Optical rotation 0°
Refractive index at 23° 1-4494
Melting-point of semi-carbazone 220° to 221°
Alcohols, phenols, and esters are also present in the oil. Guaiol is
probably present.
The ketone C 9 H 16 O does not react with bisulphite of sodium. It
yields a monobromide, melting-point 41°, and a semi-carbazone, melting-
point 220° to 221°. With sodium and moist ether it is reduced to the
corresponding secondary alcohol, which forms large crystals, melting-
point 51° (boiling-point 87° at 28 mm.). With cold 3 per cent, potassium
' permanganate solution the ketone is oxidised into geronic acid (boiling-
point 190° to 191° at 31 mm.; melting-point of the semi-carbazone 164°),
the latter, when oxidised with sodium hypobromite, giving rise to bromo-
iorm and a, a-dimethyladipic acid. This shows the ketone C 9 H 16 O to be
trimethyl-1, 5, 5-hexanone-6, a body which has not been described up to
ishe present.
CH 3. CO. CH 2. CH 2. CH 2. C(CH 3 ) 2. CO 2 H
Geronic acid.
CH 3
CH

CH 2

Trlmethyl-1, 5, 5-hexanone-6.

Emmanuel* isolated a colourless crystalline substance to which he

assigned the formula C 17 H 30 O, and the name ladaniol, but it is possible

that it is an impure form of guaiol.

The essential oils from the following two species of Cistus have been

examined by Schimmel & Co.:—

2

Oil from Cistus monspeliemis (Cistaceae). Yield 0*015 per cent.;

d 150 =» 0-9786; aD » + 1° 40'; acid number = 15*7; ester number =

31*51. The light brown oil separates off between 20° and 25° abundant

quantities of paraffin of the melting-point 64°.

Oil frpm Cistus salviifolius (Cistaceae). Yield 0*024 per cent.; d 150

« 0*9736; aD =» + 17° 20'; acid number = 16*86 ; ester number = 22*73.

This oil is yellowish-green, and behaves like the one mentioned before

with regard to the separation of paraffin.

RESEDACE>£.

OIL OF MIGNONETTE.

The fresh flowers of the mignonette, Eeseda odorata, yield traces,

about *002 per cent., of an essential oil of exceedingly powerful odour.

This oil is semi-solid at ordinary temperatures, and its chemistry is not

understood, as the oil is in itself so very rare. Indeed, commercially,

•An ordinary floral extract is generally used in preference to any direct

l

Arch. der Pharm., 250 (1912), HI. 2 Report, October, 1903, 77.