386 THE CHEMISTEY OF ESSENTIAL OILS
Eoman chamomile oil, which is the oil official in the British
Pharmacopoeia, is obtained to the extent of 1 per cent, from the re-
cently dried flowers. It is distilled in England, especially at Mitcham,
Sutton, and Long Melford. When first distilled it is of a blue colour,
but usually turns to a greenish or greenish-yellow colour on keeping.
It has a characteristic flavour and odour, but not of the nature to
justify its use in perfumery. Its characters are as follows :—
Specific gravity 0905 to 0920
Optical rotation - 3° „ + 3
C
Refractive index 1-4420 „ 1-4585
Acid value 1-5 „ 15
Ester „ 220 „ 320
It is chiefly composed of esters of angelic and tiglic acids, two
isome^ic acids of the formula C 5 H8O 2. The following esters have been
identified: isobutyl isobutyrate, isobutyl angelate, isoamyl angelate,
amyl tiglate, hexyl angelate, hexyl tiglate, and possibly esters of an
alcohol anthemol, C 10 H 16 OH. Traces of the free alcohols and acids,
probably due to decomposition of the esters during distillation, also
exist. Naudin
1
obtained from the flowers, by extraction with light
petroleum, two crystalline substances not included in the above list.
One of these he terms anthemene, and considers it to be a hydrocarbon
C1 8 H36 of the ethylene series. It forms microscopic needles melting at
63°. According to Klobb,^2 however, its formula is probably C 30 H 62.
German chamomile oil from Matricaria chamomilla has a specific
gravity about 0*940. Its colour is intensely blue, often turning greenish-
blue on keeping. It is a thick fluid becoming semi-solid on cooling,
commencing to thicken at about 14° and congealing at 1°. The oil has
the following characters:—
Specific gravity 0-920 to 0-U55
Optical rotation 0°
Befractive indexT3G 40
Acid value 9 to 50
Ester „ 5 „ 85
,, ,, (after acetylation) 115 „ 160
It is freely soluble in 90 per cent, alcohol. According to older
researches, which are not reliable, the oil consists of chamomillol
C 10 H 16 O, a terpene, and trichamomillol C30H48O3 (the blue portion of
the oil). As a matter of fact, the only constituents whose identity have
been definitely proved are esters of caproic and nonylic acids, with
traces of their decomposition products, together with a solid hydro-
carbon or mixture of hydrocarbons, which is probably responsible for
the solidification of the oil at low temperatures. This body (or mixture)
melts at 53° to 54°, and when perfectly pure is quite white. Messrs.
Schimmel & Co. consider it to be a hydrocarbon or hydrocarbons of the
paraffin series. Possibly it contains the bodies previously isolated
from Eoman chamomile oil by Naudin (vide supra). The exact nature
of the blue constituent of the oil is not known, but it is probably identi-
cal with that found in other oils, and has been named azulene. It
appears to have the formula C 15 H 18.
Power and Browning
3
have, in the course of an investigation of the
constituents of the flowers of Matricaria chamomilla, examined the
small amount (23 grms.) of essential oil obtained. The oil distilled
1
Bull. Soc. Chim., Ixi. (1884), 483.
- Ibid., vii. (1910), 940.
8
Jour. Ghem. Soc. (1914), 2280.