ESSENTIAL OILS 197 



considerable extent, so that a steam-distilled oil but rarely has exactly the 

 same odor as the flowers from which it was obtained. Extraction with 

 cold solvents and the removal of the solvent in vacuo, the temperature 

 never being allowed to rise above 40% gives oils which have exactly the 

 same aroma as the flowers. This process has the further commercial 

 advantage that such extracted flower oils can not be imitated synthetically, 

 as the change in aroma is undoubtedly due to traces of very easily de- 

 composable compounds which it will be difficult, if not impossible, ever to 

 isolate and identify. The extracted oil need fear no competition with syn- 

 thetic oils. Alcohol, ether, chloroform and petroleum ether have been used 

 as solvents for ilang-ilang oil, and the last named has given the best 

 results. Naturally, a very high grade of petroleum ether, which leaves 

 no bad smelling residue when distilled up to 40' in a vacuum of 40 milli- 

 meters, must be used as the solvent for the essential oil. Operating in 

 this manner, we have obtained oil yields of from 0.7 to 1.0 per cent. The 

 oil is of a very dark color and contains a considerable amount of resin in 

 solution. When in bulk, the odor is not particularly pleasant or very 

 strong, but when the extract is greatly diluted the pleasant aroma of the 

 flowers becomes very apparent. The physical constants of one sample of 



this oil were as follows: Specific gravitv, ^J^^ = 0.940; N ^^ =1.4920; ester 



4 D 



number 135; acetyl number 208. 



The oil is too dark to permit readings of its optical rotation to be prac- 

 ticable. These constants are seen to agree quite well with those of a very 

 high grade distilled oil, and as was stated above, the different odor is 

 probably due to traces of delicate compounds present in the extracted oil, 

 which are destroyed during the process of distillation. It is rather curious 

 to note that when this extracted oil is shaken out with water, a considerable 

 amount of resin separates, carrying the distinctive flower aroma, and the 

 separated oil then has an odor resembling that of methyl-;>kresol. 



These extracted oils should sell for a considerably higher price than 

 the best distilled oils, which fact, taken in consideration with the increased 

 yield and the impossibility of competition from synthetic oils, offers a very 

 attractive new industry to the Philippines. 



ADULTERANTS 



Regarding the use of adulterants of ilang-ilang oil, Bacon says 

 that he does not believe the practice is very general in the Phil- 

 ippines. The common adulterants are said to be turpentine, 

 coconut or other fixed oils, and kerosene. Bacon suggests va- 

 rious tests for these substances, if their presence is suspected.* 



The use of any adulteration is more emphatically the height of com- 

 mercial folly for ilang-ilang than it is for any other essential oil, for only 

 the product of the highest quality brings a remunerative price. A 10 per 

 cent increase in quantity by means of adulteration may cut the price in 

 two, or may result in an oil which can not be sold at any price. * * * 



* Bacon, R. F., Philippine terpenes and essential oils, IL Ylang-ylang 

 oil. Philippine Journal of Science, Section A, Volume 3 (1908), page 76. 



