The Limonene Group of Terpenes. 
359 
18 Spec. Gravity = 0.961 at 0°, Bouchardat & Lafont. 11 
0.952 Bouchardat & Voiry. 9 
0.9339 at 0° ) 
[ Flawitzky. 7 
0.9340 at 0° ) 
0.940 at 15° ) 
£ Schimmel & Co., Bericht, Oct ’90, p. 52. 
0.935 at 20° ) 
19 It readily absorbs bromine. The bromide, however, is solid at very 
low temperatures only. Allowed to stand with an excess of bromine di- 
pentene tetrabromide is formed. Wallach, Annalen, Bd. 230, p. 266. 
20 Tilden already observed that in alcoholic solution of “ terpinol ” acid¬ 
ulated with nitric acid crytals of terpinhydrate are generated J. C. S. 
vol. 33, p. 250. Wallach observed that very dilute hydrochloric or sulp¬ 
huric acids at ordinary temperatures favor the addition of water. 
21 Since terpinene and terpinolene are products of inversion of limo¬ 
nene and dipentene the terpineols and terpin must be regarded as deriva¬ 
tives of the hydrocarbons of the limonene group, but not of the pinene 
group. This view is supported by the conversion of the terpineols into 
dipentene tetrabromide 19 and into the dihydrohalogen derivatives of di¬ 
pentene. 
22 Comp, historical notes: Wallach (1885). 
23 List, Annalen, Bd. 67, p. 370. 
Tilden, J. C. S., vol. 33, p. 249. 
24 Wallach, Annalen, Bd. 230, p. 267. 
Flawitzky, Berichte, Bd. 20, p. 1960. 
25 From the method of formation of the monochlorhydrates of the lim- 
-onenes we know that by the action of hydrogen chloride upon terpineol 
the monochorine ester (if this is identical with limonene monohydro¬ 
chloride) could not be found. In this reaction water would be generated 
and thus the conditions favorable to the formation of the monochloride 
would be destroyed. For the formation of terpin-hydrate from the 
monochloride comp. Dissertation p. 45. 
26 Oppenheim, Annalen, Bd. 129, p. 157. This substance also appears to 
result from the action of acetic acid on pinene (B. and L! 1 ), upon limon- 
mie (L 12 ) and upon dipentene (B. and L. 11 ) 
27 Comp, methods of formation of terpin hydrate, also Wallach, An¬ 
nalen, Bd. 239, p. 19. 
28 Wallach, ibidem, p. 21. 
29 Wallach, ibidem, Bd. 230, p. 267. 
"Wallach, ididem, Tilden, J. C. S., vol. 35, p. 288. 
31 Annalen, Bd. 246, p. 267. 
32 ad I. Terpene hydrates of Flawitzky 7 . 
