Origin and Production. This oil is distilled in north eastern Russia from the needles and young twigs of Abies sibirica, Ledeb. (Abies Pichta, [Fisch.] Forb.; Ger. sibirische Edeltanne). The principal center of production is in the government Wjatka, whereas Siberia, on account of the high transportation charges, supplies but small amounts. The distillation is conducted during summer and fall. The amount produced is considerable and exceeds by far the total of all other fir needle oils.

Strictly speaking the designation Siberian fir needle oil is incorrect since the Siberian fir, Picea obovata, Ledeb. does not yield this oil. Hence this is one of the numerous instances in which the commercial designation of a coniferous oil is a contradiction to its botanical source.

Properties. d15o 0,905 to 0,925; aD - 37 to - 43°; nD20o1,470 to 1,472; ester content (bornyl acetate) 29 to 40 p. c; A.V. up to 2,5; soluble in 10 to 14 vol. of 80 p. c. alcohol, mostly with slight turbidity, and in 0,5 to 1 vol. of 90 p. c. alcohol; in rare instances the solution is opalescent.

1) Apparently derivatives of this hydrocarbon have not been prepared. Neither did Umney succeed in preparing sylvestrene dihydrochloride.

Composition. In the lowest fraction boiling below 145° a hydrocarbon C9H14 (3 to 4 p. c.) is contained which O. Aschan1) recognized as santene. It possessed the following constants: b. p. 140°; d15o 0,8698; nD19.2o 1,46960; optically inactive. The nitrosochloride melted at 109 to 111°, the nitrosite at 124 to 125°.

Like most of the coniferous needle oils, Siberian fir needle oil contains pinene, viz. /-a-pinene2) (m. p. of nitrolbenzylamine 122 to 123°) as well as B-pinene3).

It also contains about 10 p. c. of /-camphene which can be obtained in solid form by fractionation. As to its melting point, the opinion of the several observers vary. P. Golubew, who first isolated camphene from this oil, observed the melting point at 30°)4), later at 40 to 41°5) and at 50°6). J. Schindelmeiser7) observed it at 40°, and O. Wallach8) at 39° for the purified hydrocarbon. As a result of a detailed study, he arrived at the conclusion that the artificial and natural camphene represent two physically isomeric modifications.

The presence of a-phellandrene (m. p. of nitrite 106 to 107°) and of dipentene (m. p. of dibromhydrate 64°, of dichlorhydrate 49°; tetrabromide) was demonstrated by Schindelmeiser"). Both terpenes constitute together about 5,4 p. c. of the oil.

About 30 to 40 p. c. of the oil consists of /-bornylacetate10). In addition there is present the acetic acid ester of another terpene alcohol, probably of terpineol2).

From the highest boiling fraction O. Wallach and E. Grosse 11) isolated a sesquiterpene, the trichlorhydrate of which melted at 79 to 80°. It is identical with bisabolene. (See vol. I, p. 328).

1) Berl. Berichte 40 (1907), 4918.

2) Report of Schimmel & Co., October 1896, 72.

3) E. Gildemeister and H. Kohler, Wallach-Festschrift, Gottingen 1909, p. 418.

4) Journ. russ. phys. chem. Ges. 20 (1888), 477; Chem. Zentralbl. 1903, 1.835. 5) Chem. Zentralbl. 1905, 1. 95.

6) Ibidem 1910, I. 30. Comp. also Chem. Ztg. 32 (1908), 922.

7) Chem. Zentralbl. 1903, I. 835.

8) Nachr. K. Ges. Wiss. Gottingen 1907, Session of July 20. 9) Apotheker Ztg. 19 (1904), 815. - Chem. Ztg. 31 (1907), 759. 10) Hirschsohn, Pharm. Ztschr. f. Russland 30 (1892), 593; Chem. Zentralbl. 1892, II. 793.

11) Liebig's Annalen 368 (1909), 19.