As becomes apparent from the above account, the process is one of sublimation with water vapor rather than one of distillation proper, for according to this method no camphor oil whatever is obtained. Nevertheless a certain amount of oil is admixed with the crude camphor. In the "tubes", a sort of cask, in which the crude camphor is packed for shipment across the ocean, the crude oil settles to the bottom and imparts to the lower layer of camphor a dirty, pasty appearance.
From the interior both camphor and camphor oil, the latter from the newer Japanese distillation equipments, are carried by coolies in bags, boxes and tin cans to one of the six camphor offices'). Those of Formosa are located in Taipeh, Teckcham (Shinchiku), Maoli (Bioritsu), Taichu, Linkipo, and Lotong (Rato).
The production of camphor in Formosa is associated with great danger and considerable difficulties. The savage natives of the interior are still in possession of the camphor forests and regard the camphor workers as their mortal enemies. Wherever possible they attack the workmen, decapitate them and carry home the heads as trophies. The unhealthy climate and the impenetrability of the forests are the best aids of these head hunters in their battles against the Japanese. As a result, the progress of the latter into the interior is but slow1).
1) Report of Schimmel & Co., October 1900, 10.
Composition. Camphor oil is an exceedingly complicated mixture of hydrocarbons and of oxygenated constituents which belong to very different chemical types. The aldehydes are represented by acetaldehyde, the ketones by camphor and menthenone, the alcohols by terpinenol, terpineol, borneol and citronellol, the phenols and phenol ethers by eugenol, carvacrol and safrol, the oxides by cineol, the terpenes by pinene, camphene, fenchene, phellandrene, dipentene and limonene, the sesquiterpenes by bisabolene and cadinene, the acids by caprylic acid.
Arranged according to their boiling points, the constituents are as follows: 1. Acetaldehyde. This substance, which is probably never entirely absent in volatile oils, always becomes noticeable whenever large amounts of oil are rectified. In part it is lost with the first aqueous distillate, but is also found dissolved in the first terpene fraction.
2. d-a-Pinene was found in the fraction boiling below 160° (nitrosochloride; m. p. of nitrosopinene 130°2); of nitrol benzyl-amine 124°3)).
Yoshida4) obtained from the oil a strongly laevogyrate fraction [a]j - 71,1°, with the properties of l-a-pinene (chlorhydrate; nitrosochloride; nitrosopinene). Inasmuch as the lowest fractions of the oil are always dextrogyrate, the lasvorotation observed by Yoshida is noteworthy and gives rise to the suspicion that his oil was not a normal distillate.
1) A detailed account of the stirring history of the camphor industry in Formosa would lead too far. Suffice it here to refer to the interesting account given by Adolf Fischer in his book Streifzuge durch Formosa, Berlin 1900, also to the even more comprehensive work of Davidson. Both supply numerous details about camphor and camphor production.
2) Schimmel's Bericht April 1889, 8.
3) Report of Schimmel & Co., October 1903, 16.
4) Journ. chem. Soc. 47 (1885), 779; Berl. Berichte 18 (1885), 550, abstracts.
3. Camphene. The occurrence of this terpene was first pointed out by J.Bertram and H.Walbaum1). However, they did not at first succeed in establishing its identity beyond question. This was accomplished later by the preparation of isoborneol (m.p. 210°; m. p. of camphene 50°; of camphor 176°; of camphoroxime 113")-).
4. d-Fenchene (isofenchyl alcohol oxidized to isofenchone; m.p. of semicarbazone 220 to 222°)3).
5. B-Pinene (nopinic acid; nopinone, m.p. of semicarbazone 187 to 189°)3).
6. Phellandrene4) is present in such small quantities that its identification as nitrite, m.p. 102°, offered difficulties.
7. Cineol constitutes 5 to 6 p.c. of camphor oil. It was at first isolated and identified by means of the hydrobromide5), later by means of the iodol compound6).
8. Dipentene was found by Wallach7) (m.p. of tetrabromide 123°; of nitrolpiperidine 150 to 152°)8). An impure dipentene dihydrochloride, melting at 42° instead of 49°, had already been obtained by A. Lallemand9) by passing hydrogen chloride into the fraction boiling at 180°.
9. d-Limonene (m.p. of B-limonene nitrolpiperidine 110 to 1110)10).
10. Borneo/ (m.p. 203°; acid phthalate; m.p. of camphor 176°; of semicarbazone 236°; of oxime 118 to 1190)11).
11. Camphor, technically the most important constituent of the oil, separates in large quantity as soon as, in the course of the distillation, the thermometer has risen to 200°.
1) Journ. f. prakt. Chem. II. 49 (1894), 19.
2) Report of Schimmel & Co. October 1903, 17.
3) Observation made in the laboratory of Schimmel & Co. 4) Schimmel's Bericht April 1889, 8.
5) Ibidem Oktober 1888, 8.
6) Report of Schimmel & Co. Oktober 1903, 17.
7) Liebig's Annalen 227 (1885), 296.
8) Report of Schimmel & Co. April 1908, 25. 9) Liebig's Annalen 114 (1860), 196.
10) Report of Schimmel & Co. April 1908, 25. 11) Ibidem April 1904, 17.
12. TerpinenoI-1 (m. p. of terpinene dihydrochloride 50 to 52°; of glycerol 113 to 115°; A1-menthenone-3, m.p. of semicar-bazone 224 to 225°)1).
13. a-Terpineol (m.p. 35°; of phenyl urethane 112°; of nitrol piperidine 158 to 159°)2).
14. Citronellol (b.p. 225 to 227°; acid phthalate; oxidation to citronellal; m.p. of naphthocinchoninic acid 225°)1).
15. Safrol. Next to camphor this is the most important constituent of camphor oil. It was found in 1885 by J.Bertram in the laboratory of Schimmel & Co. and since then has been produced by this firm on a large scale3).