﻿THE TERPENE OILS OF MANILA ELEMI. 5 



phellandrene, boiling in vacuo almost completely within one degree and 

 pure so far as it was possible to determine. To be able to obtain this 

 substance so pure and in considerable quantity would be of especial 

 advantage in studying the constitution of this terpene and it was decided 

 to take up this problem. It was thought that the oil employed by previous 

 workers, which evidently was only partly phellandrene, had become al- 

 tered on account of the age of the resin or was derived from a different 

 variety of resin. A good quality of commercial elemi was obtained 

 from a dealer in Manila and the oil removed from a portion of this by 

 steam. When redistilled twice in vacuo it boiled from 88° to 90° at 

 50 millimeters and from 173° to 175° at ordinary pressure. The optical 



rotation was as follows: 10 a^=55°.2. Its boiling point was a little 



higher than that of the previous oil and was not so constant. The oil 

 gave a precipitate of phellandrene nitrite when it was treated with 

 nitrous acid in the cold ; on filtering, this product was somewhat gummy. 

 On treatment with bromine in cold acetic acid, a crystalline bromide was 

 obtained which, after recrystallizing, melted at 120°. The oil was 

 evidently not pure phellandrene and appeared to be a mixture of phel- 

 landrene and dipentene. 



A new quantity of elemi was then obtained from another dealer and 

 the oil derived from this in the same way as the last, boiled from 92° 

 to 94°. 5 at 51 millimeters and from 175° to 177° at ordinary pressure, 



a"i, =-\-9Q°.2. The oil gave a precipitate of phellandrene nitrite, 

 small in amount. With bromine in acetic acid, a crystalline bromide was 

 obtained which, after recrystallizing, melted at 103° to 104°, and was, 

 accordingly, limonene tetrabromide. 



A fresh sample of resin sent from the Province of Tayabas yielded an 

 oil boiling from 80° to 81°. 5 at 38 millimeters, accordingly about 3° 



Of) 



below the boiling point of limonene, a D = -f 122°. It gave a heavy 



precipitate of phellandrene nitrite and no crystalline bromide when 

 treated with bromine in acetic acid. It appeared to be almost, if not 

 quite, pure phellandrene. 



Later, two small fresh samples taken from single trees and sent to 

 the laboratory, with botanical material for identification of the species, 

 were examined. The oils were removed and purified as before. One of 

 these gave no phellandrene nitrite but a crystalline bromide having a 

 melting point of 104° to 105° was obtained. The other gave a very heavy 

 precipitate of phellandrene nitrite and no crystalline bromide when 

 treated with bromine in acetic acid. Owing to these results it was thought 

 that the great variation found in the different oils was probably due to a 

 difference in the resin obtained from different trees of the species. In 



10 This form of expression will be used throughout this article to represent the 

 optical rotation in a 10-centimeter tube at the temperature indicated. 



