﻿THE TEEPENE OILS OF MANILA ELEMI. 31 



from the phellandrene obtained from elemi oil by fractionation. From 

 the present work it can be seen that this "phellandrene" was partly limo- 

 nene, although it can also be seen that the limonene would have little 

 influence upon the value obtained. 



TERPINENE. 



Terpinene has been identified in only two essential oils, and in these 

 cases by means of its nitrite, which separates in the crystalline form on 

 treating the oil dissolved in ligroiin with nitrous acid and allowing the 

 reacting substances to stand. Both of these oils contained a mixture of 

 terpenes and from these it is possible to learn very little concerning ter- 

 pinene itself. The latter has also been shown to be present in a number 

 of products resulting from chemical operations in the laboratory, but it 

 appears always to be largely mixed with other terpenes. In general, 

 fractions of terpinene-containing oils which boil at about 180° appear 

 to have given the best yields of the nitrite. 



The purified terpene oil obtained from Sample IV was practically 

 inactive, it boiled almost completely from 174° to 175°. 5 and every 

 effort made to detect some other terpene in it was without success. It 

 gave a good yield of terpinene nitrite, which appeared very soon after 

 the addition of the nitrous acid. 



There is ever} r indication that the oil was pure terpinene, although the 

 boiling point was lower than would be expected. The following experi- 

 ments shown how poorly we are able to judge of the boiling point of 

 terpinene, if we take as a criterion that of products containing it. 



(1) A quantity of phellandrene (a -,-,=-1-122°,) was added to an equal vol- 

 ume of alcoholic sulphuric acid consisting of 2 parts alcohol, 1 part water and 

 2 parts acid, by weight. The mixture was placed in a flask and heated upon the 

 water bath, with a reflux consider, for six hours. It was then added to water, 

 the oil taken up in ether and driven over with steam; it was then redistilled 

 and divided into two fractions: (1) 175° to 177°; (2) 177° to 182°. Neither 

 fraction gave the test for phellandrene. Both gave crystals of terpinene nitrite, 

 but these appeared more quickly in (1) and were more abundant than in (2). 



(2) A terpinene-containing oil was prepared according to Wallach 26 by the 

 action of alcoholic sulphuric acid upon pinene. The oil was fractioned into 

 four portions. The second fraction, 175° to 180°, gave no terpinene nitrite, while 

 the third, 180° to 185°, gave a small amount. 



Terpinene does not differ much in physical properties (see Sample IV), 

 from limonene, except in refractive power. 



The isolation of a considerable quantity of terpinene will afford an 

 excellent opportunity for studying the constitution of this terpene. The 

 purified oil which 1 had at my disposition was not great in amount 

 and some of it was used in other work. The quantity remaining was not 



26 Ann. Chem. (LieUg) (1885), 227, 283. 



