NEW PHILIPPINE ESSENTIAL OILS. 349 



THE ESSENTIAL OIL OF CITBUS DECUMANA MUER. 



The oil in the peel of the fruit of this species, which is commonly 

 known to Americans as grapefruit or pomelo, is very difficult to express 

 and appears to have no extraordinary merit. The oil from the leaves 

 has never been described. The leaves are extremely fragrant and on 

 distillation with steam yield about 1.7 per cent of an oil having a very 

 fine odor. The constants of a sample prepared in this way were as follows : 



Specific gravity, ^^, 0.8700; ester number 10; optical rotation, A^ 



32.90° refractive index, N^- 1.4644. It is miscible with 70 per cent 

 alcohol. 



It appears probable that there are two varieties of pomelo trees. It has been 

 noted that one variety has large leaves with almost no oil; the other has a 

 much smaller leaf and the branches are quite thorny. The small, leaves are full 

 of oil cells and give the yield on distillation noted above. 



The oil contains less than 1 per cent of aldehydes. Treatment of 40 grams 

 of oil with sodium acid sulphite, in the cold, and subsequent treatment of the 

 sulphite solution, gave one or two drops only of an oil having an odor like citral. 

 Thirty-nine grams of the oil were recovered. 



Dipentene constitutes about 25 per cent of the oil, as was shown by isolating 



a fraction boiling from 174°-176°, A~=+2.35°; N^=1.4750 and specific 

 gravity —^=0.8181 which gave dipentene tetrabromide, melting point 120°. The 



fraction boiling from 195° to 200°, 15 per cent of the oil, contains linalool, as 

 was shown by oxidizing to citral by chromic acid mixture. 



CITRUS HYSTEIX, DC. 



The oil of Citrus hystrix DC. is referred to by Schimmel and Com- 

 pany ^^ as having an odor somewhat resembling that of bergamot. The oil 

 distilled here from the leaves possesses an odor very much resembling 

 that distilled from the leaves of the pomelo. Citrus decumana Murr. It 

 is very fragrant but the yield is so poor, not more than 0.08 per cent, 

 that a quantity sufficient for investigation was not distilled. The con- 



30° 

 stants of the oil are as follows: Specific gravity, :^rs^0.9150; 



30° 30° 



N^FY-^1-4C)50; A^j^^ — 10.50°: saponification number, 50.2. 



OIL OF TLANG-YLANG. 



Since the oils prepared by Bacon ^^ by extraction were of such excellent 

 quality and possessed high ester numbers, and since benzyl alcohol has 

 been found by Soden and Eojan ^^ in the distillation water of ylang-)iang 

 flowers, it was thought that perhaps some of the esters present in the 



" Semiannual Report (1901), 2. 



''This Journal, Sec. A (1909, 4, 129. 



^Ber d. Deutschen Ghem. Ges. (1901), 34, 2809. 



