The Limonene Group of Terpenes. 
341 
potassa thes esters yield the corresponding terpineols. 11-12 Presumably 
nitric and sulphuric acids are capable of forming similar compounds, 
which, however, are very unstable. The presence of water at a normal 
temperature suffices to sapoinfy them. 27 Phosphoric acid converts ter- 
pineol into the isomeric cineol. 28 With carbanil terpineol yields a crys- 
tallizable phenyl-terpinyl-urethane, which sufficiently demonstrates the 
alcoholic nature of the same. 29 Apparently the hydroxy hydrogen can 
be replaced by sodium. 30 Whereas very dilute nitric acid causes the 
formation of terpin hydrate more concentrated acid oxidizes. Potassium 
permanganate also readily oxidizes terpineol. 31 
Methods of Formation. 
I Hydration of 
Pinene. 
Limonene and Dipentene. 
II Dehydration of 
Terpin, resp. terpin hydrate. 
III Saponification of 
1. The acetates of the terpineols. 
2. The dihalogen esters of terpin. 
Preparation. 
To prepare optically inactive terpineol 25 g. of terpin hydrate are boiled 
with 50 cbcm. of phosphoric acid, specific gravity 1.12 [= 20 per cent.] 
for 10 or 15 minutes, or 50 g. of terpin hydrate are boiled in a flask at¬ 
tached to a reflux condenser with 100 cbcm. glacial acetic acid for five or 
six hours. The resulting products are distilled with water vapor. The 
dried oil is rectified and the fraction boiling between 215-218° is col¬ 
lected 8 . The optically active terpineols can be obtained according to 
Flawitzky 7 by hydration of the pinenes by means of alcoholic sulphuric 
acid, or according to Bouchardat and Lafont 1] & 12 by saponification of the 
acetic esters (obtained from the optically active pinenes or limonenes) 
by means of alcoholic potassa. 
Occurrence and Identification. 
Thus far the analysis and boiling point of terpineol and the conversion 
into dipentene dihydrochloride have served as factors for its identifica¬ 
tion. Whether these data are sufficient is rather questionable. If pos¬ 
sible the carbanil reaction should be employed. If the latter be taken 
as the only true criterion the presence of terpineol in natural products 
has not yet been absolutely proven. However, the occurrence of ter¬ 
pineol in a number of volatile oils is very probable. 
