The odor of irone is pungent, and in the concentrated condition apparently totally different from that of the violet. However, the violet-like odor becomes very distinct when the irone is dissolved in a large amount of alcohol, and the alcohol allowed to evaporate.
An investigation undertaken in the laboratory of Schimmel & Co.1) was made primarily with reference to the constituents of orris oil which are more volatile than irone, i. e. to the malodorous first distillate which is removed in the preparation of the liquid orris oil. The oil used (about 100 g.) passed over between 40 and 92° (5 mm.). It was of a golden-yellow color and had an unpleasant basic odor reminding one somewhat of skatol. Fraction 160 to 170°, obtained after repeated fractionation, contained furfurol (red coloration with solution of aniline hydrochloride in aniline). Both odor and other properties of the next higher fraction, b. p. 171 to 173°, indicated the presence of a terpene which, however, could not be further characterized (d15o0,8611; a D+ 10° 40').
When fraction 45 to 46° (10 mm.) was treated with bisulphite solution, there resulted a solid compound. Upon decomposition this yielded an aldehyde which, upon oxidation, yielded benzoic acid melting at 122 to 123°, hence it was benzaldehyde.
The fraction distilling at about 60° (5 mm.) yielded a small amount of semicarbazone (m.p. 100 to 101°) of n-decylic aldehyde.
1) Report of Schimmel & Co., April 1907, 76.
Fraction 65 to 90° (4 mm.) likewise reacted with sodium bisulphite. The aldehyde regenerated from the pure bisulphite compound distilled at 80° (5 mm.). The combustion of its semi-carbazone (m. p. 167 to 168°) yielded results pointing to the semicarbazone of nonylic aldehyde. In accord therewith was also the molecular weight determination according to Beckmann's method: found 192,5, computed 199. Oxidation with moist silver oxide yielded an oily substance which had the odor of a fatty acid, and which, when subjected to a low temperature, congealed to laminar crystals which, however, melted at little over 0°. In vacuum it boiled at 128° (4 mm.); under atmospheric pressure at 253 to 254°. The analysis of the silver salt, which was unstable toward light, indicated nonylic acid. The zinc salt of the acid, regenerated from the silver salt, melted at 127 to 128°, the copper salt slightly above 200°. Hence the aldehyde in question may be regarded as nonylic aldehyde which, upon oxidation, passes into a nonylic acid, the properties and salt of which show a close correspondence with those of pelargonic acid.
An oil obtained by fractional distillation from the fractions devoid of aldehydes and which boiled between 73 and 75° (4 mm.), yielded, upon exposure to low temperature, considerable amounts of laminar crystals of naphthalene (elementary analysis; m. p. 80 to 80,5°).
Fraction 65 to 71° (4 mm.) contained a ketone of mint-like odor. The analysis of the semicarbazone, melting at 217 to 218°, indicated a ketone of the formula C10H18O. In addition the oil contained traces of a base, a phenol, and an alcohol that reacted with phthalic acid.
Finally, it was ascertained that oleic aldehyde which, according to Tiemann and Kruger, is contained in the orris oil obtained by extraction, is not a constituent of the distilled oil. Heretofore, oleic aldehyde C18 H34 0 was not known in chemical literature. For the sake of comparison, this aldehyde was prepared by the distillation of a mixture of oleate of calcium and formate of calcium. Purified through its bisulphite compound, it had the following properties: b.p. 168 to 169° (3 to 4 mm.); d15o0,8513; nD20o 1,45571. Its odor is rather faint and resembles that of the higher fatty aldehydes. When cooled, the aldehyde congeals to a wax-like mass. Its semicarbazone melts at 87 to 89.
For the examination of the highest boiling portions of orris oil, fraction 140 to 180° (3 to 4 mm.) was used. With bisulphite no addition product resulted, hence oleic aldehyde is not a component of the distilled orris oil.
In the aqueous distillate resulting upon cohobation, the presence of the following substances was ascertained1): acet-aldehyde (b. p. 51 - 57°; reduction of ammoniacal silver solution), methyl alcohol (m. p. of oxalic acid dimethyl ester 54°), diacetyl (m.p. of osazone 242°) and furfurol (m.p. of semicarbazone 197°).
Properties. At ordinary temperature orris oil constitutes a yellowish-white or yellow mass of a fairly hard consistence, which possesses a strong odor reminding one of orris root. It melts at about 40 to 50° to a yellow or yellowish-brown liquid-).
Oil of orris root is slightly dextrogyrate. Its acid value, about 204 to 236, corresponds to an 83 to 96 p.c. content of myristic acid. Its ester value is from 2 to 10.
The so-called liquid oil of orris3) prepared by Schimmel & Co., which contains only the pleasantly smelling constituents of the oil, has the following constants: d15o0,93 to 0,94; aD + 14 to + 30°; nD20o about 1,495; A. V. 1 to 8; E. V. 20 to 40; soluble in 1 to 1,5 vol. and more of 80 p.c. alcohol.
Adulteration. In commerce a liquid or semi-liquid orris oil is occasionally met with, which is obtained by the distillation of orris roots with cedar oil or other oils; more often it is merely such a mixture of oils with a little oil of orris.
One of these oils had the following properties4): d15o 0,9489; aD - 28,25°; congealing point - 5°. Another oil5) had the following properties: d15o0,9452; aD - 21° 14'; insoluble in 80 p.c. alcohol. As became apparent from the laevorotation, a strongly laevorotatory oil such as oil of cedar or oil of gurjun balsam had evidently been added.
1) Report of Schimmel & Co., October 1908, 98.
2) In order to avoid superheating that may prove detrimental, the oil is melted by placing the bottle in warm water of about 60°.
3) Report of Schimmel & Co. April 1901, 44. 4) Ibidem April 1900, 33.
5) Ibidem April 1908, 79.
Some years ago, a mixture of 97,5 parts of acetanilide with 2,5 parts of orris oil was sold as "irisol" at enormous prices.
Statistics. The export1) of orris root from Leghorn for the last 10 years is given in the following table:
From September 1902 to August
. 840 tons
,, ,, 1903 „ „
1904 „ ,,
• 500 ,,
,, ,, 1905 „ „
• 920 „
1906 „ ,,
. 550 ,,
1907 „ ,,
. 525 „
1908 „ ,,
. 755 „
1909 „ ,,
. 760 „
1910 „ ,,
. 560 „
1911 ,, ,,
, . 690 „