﻿THE TERPEXE OILS OF MANILA ELEMI. 25 



he has given the name yS-phellandrene. With the identity of these 

 different nitrite? established, Wallach succeeded, by working with them, 

 in determining the chemical constitution of the two phellandrenes. 



So far as the terpenes themselves are concerned, there are very little 

 data, chemical or physical, which may be looked upon as reliable. The 

 physical properties recorded vary somewhat, but with tbe exception of 

 the rotation do not differ greatly from those which I have found for 

 pure phellandrene. Although phellandrene may be the predominant 

 terpene in many of the fractioned products described in the literature, 

 it must be remembered that most of the terpenes of this series are very 

 closely related in physical properties and it appears to be very often true 

 that only those of a certain class are to be found in the oil obtained from 



any one species. The optical rotation (a^) of well-fractioned phellan- 

 drene products is seldom given as being higher than ±00". Although 

 phellandrene appears to be converted completely into tbe nitrite, it was 

 found almost impossible to dry the filtered and well-washed product so as 

 to weight it accurately. This difficulty is caused by the tendency of the 

 crude substance to become slightly resinous. In solvents it undergoes 

 rapid decomposition. 



In nearly all of the terpene oils obtained in this work, which were 

 found to contain phellandrene. the latter was examined and found to be 

 a-phellandrene determined by isolating the a-nitrite described by 

 both Schreiner and Wallach. Tbe method usually employed was to 

 dissolve the crude product, dried as well as possible by presure between 

 filter paper, in a very small amount of chloroform, then filtering to 

 remove water and precipitating the nitrite with ether; it was afterwards 

 recrystallized once or twice from acetic ester. Wallach gives 11"3 to 

 113" as the melting point of the substance while Schreiner found 1'.'" 

 to 121°. During the first work which I did with this substance it was 

 recrystallized from hot solvents and the melting point seemed to depend 

 somewhat upon the solvents used. When acetic ester was employed the 

 final melting point was always 113" to 115°. It was finally found that 

 by dissolving the nitrite in acetic ester at 30° and then crystallizing in 

 a freezing mixture, the melting point given by Schreiner was obtained. 

 When the pure a-nitrite was again recrystallized from hot acetic ester, 

 its melting point was lowered to about that found by Wallach. The latter 

 used hot acetone in purifying his product and the low melting point does 

 not indicate that the substance with which he worked was impure. The 

 conclusions drawn by Wallach from his work with this substance are 

 based upon the assumption that it was free from chemical or physical 

 isomers. 



Rotation of the nitrite. — The optical rotation found by Wallach for 

 the a-nitrite obtained from two different sources was considerably 



