Origin. Under the designation shiu oil (Ger. Schiuol), the Japanese have offered, as a substitute for linaloe oil, an oil rich in linalool, which is distilled in Formosa and said to be derived from a variety of the camphor tree. Apparently this is the same oil which was examined in 1903 by K. Keimazu2). According to this investigator it seems doubtless that the oil-yielding plant in question belongs to the Lauraceae. The oil is distilled by the natives in central Formosa and is placed upon the market partly mixed with camphor oil. They call it Schu-Yu, i.e. bad-smelling oil. Inasmuch, however, as this name does not apply, Shimo-yama has named it Oleum apopinense or apopino oil after the place of production, viz., Aupin.
Under the title "Shiu oil" there appeared in 1912 an illustrated brochure by K. Nagay. As it is written in Japanese and has not been translated, nothing can be stated about its contents.
Properties. The oil referred to above as having been examined by Keimazu had the following constants: d15o0,9279; aD+17°6' to +17° 19'. Very different in their properties were 8 samples of shiu oil received in Europe from Japan in recent years: d15o0,870 to 0,8952; aD - 0°51' to - 15°30'; A. V. up to 0,6; E. V. 0,5 to 28; C10H18O content 65,5 to 90 p.c. determined by acetylation of the oil after dilution with 4 vol. of xylene; soluble in 1,8 to 10 vol. of 70 p.c. alcohol.
1) Report of Schimmel & Co. October 1911, 82.
2) Journ. of the Pharm. Soc. of Japan No. 253, March 1913; No. 258, August 1903. An abstract of the paper submitted by T. Kumagai may be found in the Report of Schimmel & Co. October 1903, 10 and April 1904, 10.
The cause for these deviations may be explained in two ways. Either the oil examined by Keimazu was adulterated with camphor oil and the substances found, viz., camphor, eugenol, safrol and cineol, were in part due to this adulterant, or the samples examined later were no normal oils but fractions greatly enriched in linalool1).
Composition. Keimazu identified the following constituents: 1. Formaldehyde (Rimini-Vitali's reaction). 2. d-a-Pinene (m.p. of nitrol piperide 118 to 119°). 3. Cineol (m.p. of hydrobromide 53 to 54°; of cineoliodol 120°). 4. Dipentene (m.p. of tetra-bromide 124 to 125°). 5. Apopinol. Keimazu obtained a fraction which upon oxidation yielded citral (elementary analysis; m. p. of naphthocinchoninic acid 200 to 202°). Inasmuch as the odor of the acetate of the alcohol differed from that of linalool, he supposed that he had a new alcohol which he named apopinol. There can be no doubt, however, that he had impure linalool. 6. d-Camphor (m. p. 176°; m. p. of oxime 117 to 118°). 7. Eugenol (m.p. of benzoate 69°). 8. Safrol (b.p. 230 to 232°; m.p. +8 to + 10°; oxidation to homopiperonylic acid, m. p. 127 to 128°; isosafrol, oxidation to piperonal, m. p. 37°).