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Eucalyptus Oil. Business in all kinds of oil has been normal, and 

 there were only slight fluctuations in the market prices. Lately the oil 

 of Eucalyptus polybractea is receiving more attention; this is now produced 

 in Australia in large quantities, and is said to be particularly suitable 

 for certain purposes. For good "Globulus" oil there was always a 

 keen demand, and the cheap kinds containing phellandrene also found 

 a ready sale. 



Eucalyptol determination. The value of eucalyptus oils con- 

 taining eucalyptol depends exclusively upon their content of eucalyptol 

 (cineol) 1 ). For this reason various methods for its determination have 

 been worked out, of which the hydrobromic acid method and the 

 phosphoric acid method are the best known. The latter has even 

 been adopted by the new U. S. Pharmacopoeia for the purpose of 

 testing eucalyptus and cajeput oils. For the sake of completeness we 

 will describe the two methods here again. 



i. Hydrobromic acid method. In a highly cooled solution 

 (freezing mixture!) of 10 cc. eucalyptus oil in 40 cc. low-boiling petroleum 

 ether, (b. p. about 40 ), absolutely dry gaseous hydrobromic acid 

 is introduced until a precipitate is no longer formed. The pure white 

 hydrobromide of cineol (C 10 H 18 O • HBr) formed is rapidly collected 

 with a suction pump, and washed with cold petroleum ether. Into 

 the filtered-off liquid, hydrobromic acid is again introduced, any pre- 

 cipitate formed is collected separately, and then added to the bulk. 

 For the purpose of removing the petroleum ether, the cineol hydro- 

 bromide is left standing for a quarter of an hour in a vacuum; it is 

 then rinsed with a little alcohol into a cassia flask, and decomposed 

 with water. The cineol separated off is brought into the neck of 

 the flask by the addition of more water, and the quantity of the oil 

 read off the scale. By multiplying with 10, the cineol-content of the 

 oil employed is obtained in per cent, by volume. 



2. Phosphoric acid method (directions of the new U. S. Pharma- 

 copoeia) 2 ). 10 cc. oil are dissolved in 50 cc. petroleum ether, and to 

 the well-cooled solution (freezing mixture!) concentrated phosphoric 

 acid is gradually added, with stirring, until the white compound 

 (C 10 H 18 O • H 3 P0 4 ) separating off acquires a yellowish or pinkish 

 shade. The crystalline mass is then filtered off with a suction pump, 

 washed with petroleum ether, pressed between tiles to remove the 

 last liquid portions, and decomposed with water. The cineol separated 

 off is estimated volumetrically, and the result recalculated in per cent, 

 by volume. 



*) In the following pages the names eucalyptol and cineol are used alternatively. 

 2 ) Report April 1906, 73. 



