According to von Soden and Muller1) sandal wood oil contains, in addition to the constituents already enumerated, strong and unpleasantly smelling phenols, also lactones with a fruity odor. The presence of borneol, both free and as ester, is also looked upon as probable. Possibly the borneol-like odor of the santenone alcohol (a-norisoborneol) may have given rise to this supposition.
Properties. East Indian sandal wood oil is a rather viscid, pale yellowish to yellow liquid. It possesses a peculiar, faint, but very persistent odor and a not unpleasant, resinous, harsh taste. d15o0,974 to 0,985; aD - 16 to --20°45', in exceptional cases lower rotation has been observed; nD20o 1,504 to 1,508; A.V. 0,5 to 8,02); E.V. 3 to 17; E. V. after acetylation not less than 196, corresponding to a santalol content of at least 90 p. c. The value of the oil increases with its santalol content, which rises as high as 94 p. c. and more in good oils.
For the solution of sandal wood oil 3 to 5 vol. of 70 p. c, 5 to 6 vol. of 69 p. c. and 6 to 7 vol. of 68 p. c. alcohol are requisite. In all cases the solution should remain clear upon the addition of more alcohol. However, turbidity is not necessarily a sign of adulteration, but may be caused by products of decomposition and resinification, due to improper methods of distillation. The solubility of sandal wood oil suffers also through age and by exposure to light and air. Such oils yield turbid solutions under the above conditions.
Inasmuch as some pharmacopoeias demand a solubility of 1:5 in a dilute alcohol the strength of which may vary from d15o 0,9675; aD - 1°2'; nD20o 1,50893; A. V. 1,8; E.V. 3,6; E. V. after acetylation 199,8 = 92,4 p.c. santalol. Soluble in 3,5 vol. and more of 70 p.c. alcohol.
1) Pharm. Ztg. 44 (1899), 259.
2) Upon water distillation (Comp. von Rechenberg, Theorie der Ge-winnung und Trennung der atherischen Ole. Miltitz near Leipzig 1910, p. 286) the acid value of the oil increases. Upon rectification and removal of the first fraction which contains the teresantalic acid, it decreases.
68 to 70 p.c, it should be pointed out that this requirement will be fulfilled only if the strength of the alcohol corresponds to the higher limit.
As already pointed out, the oils distilled in India are characterized by a dark color, an empyreumatic odor due to decomposition products, and an abnormally high specific gravity1), properties due to the irrational and crude methods of distillation.
An oil distilled in India and examined by Schimmel & Co.1) had the following properties: d15o 0,9898; aD + 8°; A. V. 3,7; E.V. 7,1; E.V. after acetylation 205,3 = 95,4 p.c. total alcohol (C15H210); insoluble in 70 p.c. alcohol, soluble in 1 vol. and more of 80 p. c. alcohol. As indicative of the presence of decomposition products, its high specific gravity2) should first be pointed out. In good oils this never exceeds 0,985. There was also an exceedingly unpleasant, fish oil odor that could not be removed by rectification. A further disadvantage is to be found in its insufficient solubility. In spite of its high santalol content the oil was of inferior quality.
The following oils were distilled from wood not obtained from India proper, Macassar or Timor. Although most of the properties are fairly normal, deviations were observed especially in the optical rotation. It could not be ascertained with certainty whether these woods were derived from Santalum album or from a closely related species.
Oil from wood of the New Hebrides.
*) Report of Schimmel & Co. October 1910, 115.
2) The high specific gravity in connection with Indian oils has been previously observed. (Chemist and Druggist May 26th, 1894). The cause thereof is to be sought in the prolonged contact of the oil with the hot water. Conroy has demonstrated that by heating sandalwood oil with water of 50° for ten days its specific gravity increased from 0,975 to 0,989. (Chemist and Druggist August 19th, 1893).
Oil from Tahiti Wood1).
d15o0,9748; aD - 8°29'; nD20o1,50848; A. V. 2,0; E. V. 5,1; E. V. after acetylation 203,6 = 94,4 p. c. santalol. Soluble in 4 to 4,5 vol. and more of 70 p. c. alcohol.
Oil of Sandalwood from Thursday Island.
d18o0,9635 to 0,9687; aD - 27° 10'to - 37°30'; nD20o1,504 to 1,507; A. V. to 2,0; E.V. after acetylation 196,7 to 202,6 = 90,6 to 93,8 p.c. santalol. Soluble in 4 to 5 vol. and more of 70 p.c. alcohol.
Concerning the properties of New Caledonia sandalwood oil see p. 349.
Examination. Owing to the slight variations in its physical constants to which oil of sandalwood is subject, additions of all kinds can be readily ascertained with certainty by means of its specific gravity, its optical rotation and its solubility in 70 p.c. alcohol. The principal adulterant, viz., cedarwood oil2) can be detected by the increase of the optical rotation and by the diminution of the specific gravity and solubility. Practically the same changes are brought about by the oils of copaiba balsam and gurjun balsam. Copaiba balsam oil, however, usually causes a slight lowering of the optical rotation. West Indian sandalwood oil, which is occasionally used as adulterant, rotates to the right and is very difficultly soluble in dilute alcohol.
How frequently sandalwood oil is adulterated may be seen in a communication by Schimmel & Co.3) according to which not one of 6 samples obtained in the London market contained the required percentage of santalol. The oil sold in capsules4) is even more frequently adulterated with substances such as castor oil5). In one instance terpineol") was found in an oil; in an other, guaiac wood oil and an ester of benzoic acid7).
1) Presumably derived from Santalum Freycinetianum, Gaud. 2) Comp. Report Schimmel & Co. April 1912, 112.
3) Ibidem October 1910, 116.
4) R. Peter, Pharm. Ztg. 48 (1903), 573. - P. Runge, ibidem 49 (1904), 671. - G.Wendt, ibidem 50 (1905), 898. - E.J.Parry, Chemist and Druggist OS (1906), 951.
5) Report of Schimmel & Co. April 1906, 73.
6) E. ). Parry, Chemist and Druggist 08 (1906), 211.
7) Report of Schimmel & Co. October 1911, 81.