After several distillations in vacuum, fractions A and B yielded a fraction 173 to 180° (13 mm.), from which vetivenol could be removed by means of phthalic acid anhydride. It would seem therefore to be a primary alcohol. When reduced with hydrogen in the presence of platinum, vetivenol can be reduced to the tricyclic dihydrovetivenol, C15H260: b. p. 176 to 179° (17 mm.); d20o 1,0055; aD + 31°; nD 1,51354. Vetivenol (tricycl.) yields an acetate b. p. 180 to 184° (19 mm.); d20o 1,0218; aD + 28°48'; nD 1,50433; mol. refr. found 75,91, computed for C17H2602/"75,61.
Upon saponification of fraction C, an oil resulted which, after repeated distillation, yielded a fraction with a boiling point of 178 to 185° (19 mm.); d2(r 1,0137; aD + 52°12'; nD 1,52822; mol. refr. found 66,81, computed for C15H24O/"66,00, computed for C15H240/267,71. Hence there is a mixture of di- and tricyclic vetivenol. The acid of fraction C proved to be vetivenic acid. Fractions A and B likewise contained a dicyclic primary vetivenol which is probably identical with that of fraction C. Tricyclic vetivenol was also contained in these fractions.
After repeated fractionation in vacuum, finally over sodium, two hydrocarbons were isolated from fraction A:
I. B.p. 123 to 130° (16 mm.); d20o 0,9355; aD+2°16'; nD1,51126; mol. refr. found 65,32, computed for C15H24/= 64,45, computed for C16H24/=66,15.
II. B.p. 137to 140°(16mm.); d20o 0,9321; aD-10°12'; nDl,51896; mol. refr. found 66,42, computed for C15H24/" 64,45, computed for C15H24/2 66,15.
According to the molecular refractions, fraction I may be regarded as essentially a tricyclic hydrocarbon with one double bond, whereas fraction II may be a dicyclic hydrocarbon with two double bonds. These hydrocarbons are probably related to the vetivenols C15H240 as the santalenes to the santalols and are to be differentiated as di- and tricyclic vetivenes.
The examination of a Reunion vetiver oil (d20o 0,9916 and 0,9982; aD + 2406' and +31°; nD 1,52429 and 1,52517) yielded somewhat different results. Of the high boiling vetivenol vetivenate little or scarcely appreciable amounts are present. Like the oil distilled by Schimmel & Co., the Reunion oil contains tricyclic and dicyclic vetivene. Tricyclic and dicyclic vetivenol also occur in this oil.
When acted upon with phosphorus trichloride in petroleum ether solution, the vetivenol from Reunion oil (b. p. 161 to 164° under 9 mm.) yields a chloride b. p. 140 to 147° (10 mm.) (d20o 0,9679; aD - 24°; nD 1,52640). When reduced with sodium and alcohol, an artificial vetivene resulted: b. p. 121 to 127° (9 mm.); d20o0,9296; aD - 25° 48'; nD 1,51491; mol. refr. found 66,1, computed for C15H24/2 66,15. Semmler, however, obtained different results when he reduced, with sodium and alcohol, the chloride which had likewise been prepared with the aid of phosphorus pentachloride, but had not been rectified in vacuum. After the resulting hydrocarbon had been distilled over sodium and then shaken for a longer period with a 3 p.c. permanganate solution, it revealed the following properties: b. p. 123 to 129° (10 mm.); d20o 0,9288; aD + 6°12'; nD 1,50682; mol. refr. found 63,88, computed for C15H24/= 64,45. To what extent, if any, the artificial vetivenes are identical with the natural ones, will have to be revealed by further investigations.
The reduction of the crude vetivenol from the Reunion oil with hydrogen in the presence of finely divided platinum, apparently yielded tricyclic dihydrovetivenol and dicyclic tetrahydro-vetivenol. In small part the vetivenol was thereby reduced to a hydrocarbon.
In the aqueous distillate of vetiver oil the presence of methyl alcohol, furfurol and diacetyl (monophenylhydrazone, m. p. 133 to 134°; hydrazoxime, m. p. 158o; dimethylbishydrazimethylene, m. p. 158°; trimethylglyoxaline) has been proven1).
1) Report of Schimmel & Co. April 1900, 45.
Botanical Origin. Citronella oil is distilled from the grass of Cymbopogon Nardus, Rendle. The name Nardus is due to the mistaken identity, by various botanists, of this plant with the Nardus Indica of the Ancients. Linne originally named the plant Andropogon Nardus. The designation Cymbopogon Nardus has recently been reintroduced by O. Stapf1). Others have associated this grass with Calamus aromaticus-) of antiquity. Nicolaus Grimm, who lived as physician in Colombo toward the close of the 17. century, named it Arundo Indica odorata. He knew that it grew abundantly in the vicinity of Colombo and that a volatile oil was distilled therefrom. Subsequently citronella grass was frequently confounded with lemon grass.
With the exception of Ceylon, where the grass is reported to occur wild also3), citronella grass is found in the cultivated state only. It is cultivated primarily in the southern part of Ceylon, in the peninsula of Malacca and in Java. These countries supply the citronella grass of commerce. In recent years attempts at cultivation have been made in the West Indies, in the Seychelles and the South Sea islands. In tropical East Africa the grass is said to occur frequently4).
The managrass of Ceylon, Cymbopogon confertiflorus, Stapf of Ceylon is regarded as the mother plant of the citronella grasses.
For the purpose of distilling the commercial oil, two varieties of citronella grass are cultivated, Maha Pengiri (Maha Pangiri)5) and Lena batu (Lana Batu). The first kind is also known as "old citronella grass" or "Winter's grass". It is cultivated prin1) The Oil Grasses of India and Ceylon. Kew Bull. 1906, 297; Report of Schimmel & Co. April 1907, 20.
2) According to Royle, this name applies to palmarosa grass or Cymbo-pogon Martini, Stapf. Hence he suggested the name Andropogon Calamus aromaticus (comp. Stapf loc. cit. p. 336).
3) J. F. Jowitt, Annals of the Royal Botanic Gardens, Peradeniya, Vol. IV, pt. IV, December 1908, p. 185.
4) A. Moller, Berichte d. deutsch. pharm. Ges. 7 (1897), 501.
6) Maha means large and Pangiri signifies the nebulae of oil particles that result when orange or lemon peels are' pressed.
cipally in Java, also in the Malacca peninsula. In Ceylon it was cultivated only temporarily by Winter, a well-known distiller of citronella oil of Baddagama, hence the name. According to Jowitt1) this grass occurs wild in Ceylon and constitutes a variety distinct from the managrass. Probably by crossing2) of the two the third variety, the lena batu grass, has resulted. According to Stapf's observations, the Maha Pengiri and Lena-batu can not be distinguished morphologically. However, the habits of the two plants are different as are also the two volatile oils. For this reason the two varieties are distinguished botanic-ally: the Maha Pengiri variety is known as Cymbopogon Winterianus, Jowitt (Andropogon Nardus Java, de Jong), the Lena batu variety as C. Nardus, Rendle, lena-batu (A. ISardus Ceylon, de Jong).
The maha pengiri grass is distilled but little in Ceylon. It yields the Java citronella oil.
The lena batu variety, also known as "new citronella grass" supplies the bulk of the Ceylon citronella grass and yields the ordinary Ceylon citronella oil of commerce.