Properties. Palmarosa oil is colorless or light yellow, occasionally it is colored green by copper. It has a pleasant odor reminding of roses. Its sp. gr. is 0,887 to 0,90. Its optical properties vary, some oils being slightly dextrogyrate, others slightly laevogyrate, still others optically inactive. aD + 6 to - 3°, mostly between +1 and - 2°; nD20o1,472 to 1,476; A. V. 0,5 to 3,0; E. V. 12 to 48; E. V. after acetylation 226 to 274 corresponding to 74,8 to 94,8 p.c. of total geraniol. In 1,5 to 3 and more parts of 70 p.c. alcohol it dissolves to form a clear solution; in very rare instances opalescence to turbidity has been observed. Oils with a higher geraniol content are soluble in from 3 to 4 vols, and more of 60 p.c. alcohol.

Examination. Palmarosa oil of commerce is frequently adulterated. As adulterants gurjun balsam oil, cedar oil, turpentine oil, petroleum (kerosene, paraffin oil) and cocoanut oil have been observed1). All of them betray their presence by the insolubility of the oil in 70 p.c. alcohol. Oils adulterated with cocoanut oil as a rule congeal when placed in a freezing mixture. Petroleum and turpentine oil reduce the specific gravity, whereas fatty oil raises it. In doubtful cases it is advisable to make an acetyla-tion test. Oils with a lower geraniol content than 75 p.c. are to be rejected.

An adulteration with alcohol, together with another admixture (citronella oil fraction), has been observed by Schimmel & Co.2).

Composition. The older statements concerning the botanical source and the physical properties of palmarosa oil are so conflirting that it seems doubtful whether the investigators really worked with palmarosa oil or not1).

1) Schimmel's Bericht April 1888, 22; April 1889, 20; Report of Schimmel & Co. October 1890, 35.

2) Report of Schimmel & Co. April 1907, 56.

The first investigation with unquestionable material was conducted by O. Jacobsen2). He demonstrated that the bulk of the oil consists of an alcohol C10H18O which boils between 232 and 233° and which he designated geraniol. He also discovered the compound of geraniol with calcium chloride, which has become so important in the isolation of the pure alcohol, since it is readily decomposed into its components by water. Later Semmler3) verified the formula C10H18O and recognized the aliphatic character of geraniol. Thus geraniol became the first representative of the aliphatic terpene alcohols, a new class of compounds that has acquired such importance in the study of the volatile oils.

The amount of geraniol in palmarosa oil varies between 75 and 95 p. c. Of this the greater part is free, and from 3 to 13 p. c. are ester. As determined by E. Gildemeister and K. Stephan4) by means of the silver salts, the acid components of these esters, acetic and n-capronic acids, occur in about equal parts.

Of terpenes palmarosa oil contains but very little, viz. about 1 p. c. of dipentene (m. p. of tetrabromide 125°, of nitrolbenzyl-amine 109 to 110°). Of methylheptenone (m.p. of semicarbazone 1350)5) traces are also present.

1) J. Stenhouse (Liebig's Annalen 50 [1844], 157) reports on an investigation of an East Indian grass oil from Andropogon Iwarancusa, the odor of which reminded of rose oil, and the taste of which resembled lemon oil. Upon distillation it yielded a hydrocarbon C10H16 boiling at 170°. It may be assumed with a fair degree of certainty that this grass oil was not palmarosa oil but citronella oil from Andropogon Nardus, L, also known as Andropogon Iwarancusa, Roxb. Citronella oil contains a terpene boiling at 160° (camphene) whereas such low boiling constituents are wanting in palmarosa oil.

). H. Gladstone (Journ. chem. Soc. 17 [1864], 1ff.; Jahresb. f. Chemie 1863, 548) describes an Indian geranium oil of the sp. gr. 0,943 at 21°, which he regarded as identical with the East Indian grass oil from Andropogon Iwarancusa. It does not become apparent from the statements of this author what oil he had in hand.

2) Liebig's Annalen 157 (1871), 232.

3) Berl. Berichte 88 (1890), 1098.

4) Arch, der Pharm. 234 (1896), 328.

5) Report of Schimmel & Co. April 1905, 47.

In addition to geraniol, Flatau and Labbe1) claim to have found a second alcohol, viz. citronellol. As Schimmel & Co.2) have pointed out, this statement is incorrect as is likewise the statement by the same investigators3) that palmarosa oil contains a fatty acid C14H2802 of the m. p. 28°. According to the investing. 23. Copper containers for palmarosa and gingergrass oils.

122 Palmarosa Oil 25

Gations of Schimmel & Co.4) pure palmarosa oil contains no such acid and the findings of the French chemists can be explained only by assuming that their oil was adulterated with cocoanut oil or some other fatty oil. Hence the acid C14 H28 O2 is not a constituent of palmarosa oil, but an adulterant.

1) Compt. rend. 126 (1898), 1725. - Bull. Soc. chim. III. 19 (1898), 633.

2) Report of Schimmel & Co. October 1S98, 59.

3) Compt. rend. 126 (1898), 1726.

4) Report of Schimmel & Co. October 1898, 28.

According to Elze1), farnesol (comp. vol. 1, p. 399) is contained in palmarosa oil.

Production and Commerce. The principal commercial and export center is Bombay. Most of the oil is shipped to Europe. Formerly the oil was shipped to the ports of the Red Sea, from there overland to Cairo and thence to Constantinople and the rest of Europe. On this account the oil was formerly designated "Turkish geranium oil" without, however, any justification. At present palmarosa oil is shipped from Bombay directly to Europe. In Bombay the oil is graded and filled into large tin-lined copper ramieres or pots. Formerly these averaged from 100 to 200 lbs., now most of them have a net capacity of 250 lbs. These containers are protected by a net work of ropes (fig. 23) and are not crated. It is estimated that the export from Bombay averages 50,000 lbs. annually. Inasmuch, however, as the actual exports for the year 1902/3 amounted to 125,595 lbs., the above figure would seem to refer to the production of Bombay and the Central Provinces. The balance probably came from the southern provinces in which the production has increased materially in recent years.

The exports in volatile oil from Bombay (principally palmarosa oil with about one-fourth gingergrass oil) are given in the following table:

1896/97 . . . .

8199

gals.

at a value of

149553

rupees

1897/98 . . . .

10 776

,,

,, ,, ,, ,,

209691

,,

189899 . . . .

16000

404140

1899/00 . . . .

10400

,, ,, ,, ,,

278005

,,

1900 01 . . . .

12834

,,

,, ,, ,, ,,

341 670

,,

190102 . . . .

19 641

,,

,, ,, ,, ,,

610 783

,,

1902 03 . . . .

18872

,,

,, ,, ,, ,,

523630

,,

1903/04 . . . .

20680

,,

,, ,, ,, ,,

538774

,,

1904 05 . . . .

18742

,,

,, ,, ,, ,,

465209

,,

190506 . . . .

23436

,,

,, ,, ,, ,,

551 425

,,

Formerly the principal import countries were England, Egypt and Turkey. Arranged according to the amount imported, they are at present Germany, France, England and the United States of America.

1) Chem. Ztg. 34 (1910), 857.