In connection with a Spanish oil distilled at Chinchilla, Schimmel & Co. observed the following properties: d30o0,8247; aD-1°23'; nD26o 1,45212; congealing point +27°; A. V. 3,3; E. V. 10,7; E.V. after acetylation 135,5 = 41,5 p.c. total geraniol; paraffin content 50 p.c, E.V. of the paraffin 7,0. The constants of another Chinchilla rose oil were found as follows'2): d30/15o0,844; aD - 2°; nD 1,565; m. p. 27 to 28°; paraffin content 33,3 p.c; m. p. 15° of the paraffin 31,31°.
Concerning rose oils obtained by the extraction method, H. von Soden8) makes the following communication: 8000 kg. of French roses yielded 0,052 p.c. of volatile oil which congealed between 5 and 7°; d15o0,967; aD17o - 1°55'; E.V. 4,6; E.V. after acetylation 295. By means of phthalic acid anhydride 75 to 80 p.c of alcohols were isolated from the oil, 75 p.c. of which consisted of phenylethyl alcohol and 25 p.c. of the other primary alcohols commonly found in oil of rose.
45 kg. of German roses yielded 0,0107 p.c. of ethereal extract oil with a congealing point of +12°; d19o0,984; aD17o+ 0° 9'; A.V. 3; E.V. 4; E.V. after acetylation 313,5; content of phenylethyl alcohol 75 p.c, of aliphatic alcohols (primarily) 25 p.c
Composition. Not long after the introduction of elementary analysis the first combustions of rose oil and its stearoptene were made by Saussure in 1820*). A second analysis by R. Blanchet') soon followed. Whereas the combustion of the oil revealed little more than its oxygen content, that of the stearoptene revealed its hydrocarbon character. Blanchet regarded the substance as a terpene C10H16. It was not until 1869 that Fluckiger1) looked upon it as a representative of the paraffin series. The molecular weight determination made later by F. B. Power2) under his direction yielded results that agreed with the formula Cl6H34. R. Bauer3) who made numerous observations on the distillation of Turkish oil of roses in Bulgaria and who made detailed reports thereon from 1867 to 1872, claimed that the odorless stearoptene could be converted into fragrant eleoptene by oxydation, also that reversely, the eleop-tene could be artificially reduced to stearoptene. These remarkable claims have not been substantiated by later investigations. About the same time (1872), Gladstone4) occupied himself with the study of the liquid portion of the oil, the boiling point of which he found to be 216°. The first detailed investigation of rose oil was made by C. U. Eckart5). As principal constituent of German as well as Bulgarian oil he found, in 1890, an alcohol of the formula C10H18O to which he assigned the name rhodinol. Although he observed a great similarity between the new alcohol and geraniol, Eckart declared rhodinol to be different from geraniol. He also proposed a formula to express this difference structurally. It is possibly largely due to the incorrect boiling point, which was found at 216° in correspondence with Gladstone's observation, instead of at 229°, that Eckart did not recognize the geraniol which he had in hand.
1) Berichte von Roure-Bertrand Fils October 1902, 24. 2) Perfum. and Essent. Oil Record 3 (1912), 3. 3) lourn. f. prakt. Chem. II. 69 (1904), 265.
4) Annal. de Chim. et Phys. II. 13 (1820), 337.
5) Liebig's Annalen 7 (1833), 154.
Shortly thereafter, namely in 1893, W. Markownikoff and A. Reformatzky6) claimed that the formula C10H20O should be assigned to the principal constituent of Bulgarian oil of rose and gave to it the name roseol. At the same time, however, Barbier1) had arrived at the conclusion that Eckart's formula C10H18O was the correct one. This conclusion was still farther verified by Tiemann and Semmler2) who recognized the identity of Eckart's rhodinal with citral, the aldehyde C10H16O corresponding to geraniol. The conflicting results obtained in the investigations of Eckart on the one hand and of Markownikoff and Reformatzky on the other hand caused Bertram and Gilde-meister8) to take up the investigation of oil of rose. They ascertained that the bulk of both German and Bulgarian oils of rose consists of geraniol C10H18O, the alcohol discovered by Jacobsen in 1870 in palmarosa oil (b. p. 229 to 230°) and that rhodinol is impure geraniol4).
1) Pharmaceutical Journ. II. 10 (1869), 147. - Zeitschr. f. Chem. 13 (1870), 126; Jahresber. f. Chem. 1870, 863.
2) Fluckiger, Pharmakognosie. III. ed., p. 170.
3) Neues Jahrb. f. Pharm. 27 (1867), 1 and 28 (1867), 193; Jahresber. d. Pharm. 1867, 350. - Dingler's polyt. Journ. 204 (1872), 253.
4) Journ. chem. Soc. 25 (1872), 12. - Pharmaceutical Journ. 111.2(1872), 747; abstract Jahresber. f. Chem. 1872, 816.
5) Arch, der Pharm. 229 (1891), 355. - Berl. Berichte 24 (1891), 4205. - Th. Poleck, Berl. Berichte 23 (1890), 3554.
6) Journ. f. prakt. Chem. II. 48 (1893), 293.
However, geraniol is not the only alcohol contained in oil of rose. Hesse5) suspected that the alcohol reuniol C10H20O, found by him in pelargonium oil, might also be contained in rose oil. Tiemann and Schmidt6) proved the identity of reuniol with citronellol, the reduction product of citronellal.
Another important alcoholic constituent is phenylethyl alcohol. It is found in small amounts only (abt. 1 p. c.) in the oil distilled according to the ordinary methods and can be obtained by cohobation only if special methods are employed.
1) Compt. rend. 117 (1893), 177.
2) Berl. Berichte 26 (1893), 2708.
3) Journ. f. prakt. Chem. II. 49 (1894), 185.
4) A lively controversy has arisen as to whether the alcohol C10H18O should be named geraniol in accordance with the well-established name given to it by Jacobsen, or rhodinol, the name given to an impure compound by Eckart. Without going into the merits of this controversy, the literature thereon may here be referred to: H. Erdmann and P. Huth: Zur Kenntnis des Rhodinols oder Geraniols. Journ. f. prakt. Chem. II. 53 (1896), 42. - J. Bertram and E. Gildemeister: Uber Geraniol und Rhodinol. Ibidem II. 53 (1896), 225. - A. Hesse: Ober die vermeintliche Identitat von Reuniol, Rhodinol und Geraniol. Ibidem II. 53 (1896), 238. - H. Erdmann: Unter-suchungen uber die Bestandteile des Rosendls und verwandter atherischer Ole. Ibidem II. 56 (1897), 1. - Bertram and Gildemeister: Die Bestandteile des Rosenols und verwandter atherischer Ole. Ibidem II. 56 (1897), 506. - Th. Poleck: Zur Rhodinolfrage. Ibidem II. 56 (1897), 515 and Berl. Berichte 31 (1898), 29. - Bertram and Gildemeister: Zur Rhodinolfrage. Ibidem 31 (1898), 749.