Chemistry of Essential Oils

RUTACE^E

Specific gravity at 25°

Optical rotation

Saponification value

On fractionation the

fractionated with a 3-bulb

Frac- Fractionation

tion Temperatures

No. °C.

1 154-170

2 170-180

3 180-190

4 190-200

5 200-220

6 220over

7

oil gave

LeBel

Per cent.

Distilled

over.

8-51

54-83

9-47

2-48

8-75

10-22

5-01

the following results.

fractionating column:—

Specific

Gravity

15° C.

0-8810

0'9119

0'9215

0'9290

Q'9635

0-9365

0-9171

Specific

Rotation

at 15° C.

+ 16-42

+ 5-85

+ 6*56

+ 9-52

+ 36-42

+ 18-85

0-9295

+ 7° 28'

1-4713

54-3

The oil

Index of

Refraction

15° C.

1*4590

1-4585

1-4650

1-4665

1-4817

1*4793

1-4884

was.

Fractions 5, 6, and 7 were obtained under reduced pressure at 150°-180°. The

boiling-points of these fractions were redetermined at atmospheric pressure.

The oil was found to contain about 8 per cent, of pinene, 60 per cent,

of eucalyptol, 9 per cent, of borneol, 19 per cent, of linalyl acetate, with

a little camphor, methyl salicylate, and sesquiterpene alcohol.

From the dry twigs of Calycanthus floridus Miller, Taylor, and Eskew

1

obtained from 0'25 to 0*53 per cent, of a pale yellow essential oil having

a camphoraceous odour. Its characters are as follows:—

25°

Specific gravity at- 0-9136 to 0*9209

Optical rotation + 2*84°

Refractive index at 26° 1-4675

Saponification value 12*5

+ 6-6°

1-4753

16-6

(after acetylation)... 65*7 75-1

Eucalyptol is present in the oil, as well as a-pinene, salicylic acid (?),

borneol and, possibly, linalol. Bornyl esters of formic and acetic acids

are also" present.

RUTACEit.

LEMON OIL.

This oil, one of the most important of all the essential oils from the
commercial point of view, is obtained by various processes from the fresh
peel of the ordinary lemon, Citrus limonum (Citrus medico, subsp. Lim-
onum). The tree is a native of India, and was introduced into Southern
Europe, probably first into Spain, and thence to the South of France and
Italy. There are numerous varieties and hybrids, but the ordinary lemon
forming the fruit of commerce is the Genoese lemon. This is cultivated
on the Mediterranean littoral, especially between Nice and Genoa, in
Calabria, Sicily, Spain, and Portugal, and on nearly the whole coast of
Liguria. Many of the British Colonies are now cultivating this fruit,
Australia for many years past having filled its own requirements for
lemons; the trees are also extensively grown in New South Wales,
Florida, California, and Jamaica, and will, probably, shortly produce the
oil in considerable quantities. The oil is obtained in the South of Europe
between the months of November and March, or April, and the processes
used are the following: (1) The spugna or sponge process, by which

1Jour. Amer. Chem. Soc., 36 (1914), 2182.