﻿THE TERPENE OILS OF MANILA ELEMI. 10 



melted from 118° to 120° with darkening,, but in appearance and solubility 

 it resembled dipentene tetrabromide. On recrystallizing again, it melted 

 at 123° to 121°. This purified bromide was unquestionably that of 

 dipentene, although the crude product appears to have been a mixture, 

 for after the first recrystallization it was still impure. 



At this point it was found that the purified oil gave a decided test for 

 phellandrene. The rotation of the oil was also found to have changed 

 from -f-l°.7 to — 1°.6. After standing for five or six days longer, the 

 oil gave a rotation of — 9° .8 and one month after this of — 31f '.5, tints 

 demonstrating that a rapid change was taking place spontaneously. 

 Three weeks later, the oil, which had stood in a cork-stoppered, partly 

 filled flask, was distilled with steam. A small proportion of viscous, non- 

 volatile matter remained, probably the result of oxidation of the oil 

 upon standing. The distillate was separated from water and without 



further drying gave a jy = — 38°. To judge from this value, in compari- 

 son with that obtained three weeks previously, it was evident that the 

 change taking place had about reached completion. In amyl alcohol and 

 ether the oil now yielded a very good quantity of a crystalline bromide 

 which was filtered off, washed and recrystallized from- a mixture of acetic 

 ester and alcohol. Melting point, 122° to 124°. 0.24 gram of the substance 

 dissolved in about 8 cubic centimeters of acetic ester and placed in a 10- 

 centimeter tube showed no appreciable rotation, so that the product 

 apparently contained very little if any limonene tetrabromide. Certainly, 

 the rotation of the oil can not be accounted for by the presence of lsevo- 

 limonene. A good quantity of the bromide was also obtained in acetic 

 acid. After crystallizing once from a mixture of acetic ester and alcohol, 

 it melted at 120° to 123° ; on recrystallizing from acetic ester the melting 

 point was 125°. The product melting at 120° to 123° remained perfectly 

 colorless on fusion, thus differing markedly from that obtained from the 

 oil after four or five days' standing. An attempt was now made again to 

 prepare phellandrene nitrite from the oil and to determine its rotation. 

 Although the presence of phellandrene in the oil was readily shown, it 

 was now found impossible to isolate the nitrite in the presence of so 

 much dipentene, the final product being a small amount of viscous 

 matter adhering to the sides of the flask. This result is, of course, quite 

 different from that obtained two months previously. 



There appears to be no doubt but that the oil when first isolated was 

 nearly pure terpinolene : that this terpinolene changed completely on 

 standing into dipentene. a small amount of dextro-phellandrene and an 

 unknown laevo-rotatory terpene. The boiling point of this terpinolene 

 is considerably lower than that obtained by Baeyer for the product 

 formed on reducing the tetrabromide. The present case is the only one 

 in which the presence of terpinolene has ever been noted in a natural 

 product. 



