36 



(3) Fencheite, obtained artifidally from ftnchoue, a constituent of many fennel oils. 



(4) /.imu/icHC occurs in orange-peel oil, in oils of lemon, lierganiot, cummin, etr. 



(5) Dipeidenc, obtained artificially from pineue. Occurs in Russian an 1 Swedisli turpentine. 



(6) Siih-eslrene. occurs in Russian and l^wedisli turpentine. 



(7) Phelandreiie. occurs in the oils of l)itter fennel and water fennel, elemi. eucalyptus. 



(8) Tfipiiieiir. occurs in oil of cardamom. 



(9) Terpinohne. only slij^htly known. 



Ill.—I'olijlerpoici, of the formula (Gr,HK)„, as cedrenes Ci=,H.,|, caoutcliouc (CjH„)„, etc. 



The hydrocarbon of the American and French oils of turpentine is pinene. It is dextro- 

 rotatory when obtained from tlie American turiientinc ()il, and is known as austro-fcrrhinfhciic or 

 aii.stmlcne; licvo-rotatory wlien obtained from the Frencli turpentine oil, and is known as tere- 

 hinthenc. Otherwise the two hydrocarbons agree entirely in specific gravity, boiling point, and 

 behavior towards chemical reagents. 



The hydrocarijon of the Russian oil of turpentine is sylvc.strenc. It is dextro-rotatory, and 

 has a higher boiling point than pinene. The latter boils at io.jo to 156° C, the former at ITo'^ to 

 178° C. 



But even the turpentine oils of high grade as found on tlic market do not consist of pure 

 pinene; especially is this true of ordinary oil of turpentine, which is obtained I'rom the cruder 

 turpentine by a single distillation with steam. Different samples vary from (me another consider- 

 ably in their specific rotary power as well as in their boiling point. 



American oil of turpentine has a density of O.SGio to O.cSTO-^'. According to Allen* it begins 

 to boil at a temperature l)etwecn 150° aiid \i',0o (].^ a]id fully iiasses over below 170^ ('. ''A good 

 sami)le of rectified American oil will give it(l-'.i;5 ]ier cent of distilhite l)elow KioO, the greater part 

 of which will pass over between 1.">S^' and l(!()'^J"t, while in the experience of J. 11. Long,| "In 

 the examination of a large number of pure commercial samples of turpentine oil it was observed 

 that the boiling point was uniforndy at l.V.^ to IT.lP, and tliat .S.'. per cent of the samples distilled 

 between 155o and KiS^. The distillation is practically complete below l8o^ C." 



Then, again, as found by Long, the vapor densities of many samjiles of oil are too high to 

 allow tlie formula tl,„II,„ for the entire oil. Fractions of different boiling points show different 

 degrees of specific rotation. All this would indicate that ordinary turpentine oil contains hydro- 

 carbons heavier than pure pinene, OioHiii- They are ju'obably either isomeric with pinene, but of a 

 higher boiling |)oint, or may belong to the polyterpenes. 



Still less do we know of the source of these hydrocarbons. Whether they are produced by 

 the tree simultaneously with pinene, and are, therefore, to be found in the oleoresin, or whether 

 they are all or in i)art i)roduceil by external agencies after the turpentine has been dipped, can not 

 be answered. Probably the formation of these other hydrocarbons takes ])lace in both ways spon 

 taneou.sly in the tree and by some intluences outside the tree. 



Indeed, all terpenes have this property in common that they easily undergo change, from optic- 

 ally active to inactive, fromhemitcriK-nes to terpenes and polyterpenes. The change can be brought 

 about either by heat alone, or by heating the terpenes with salts or acids. So, when a sample of 

 American turpentine oil of +18.0° was heated to 200° C. for two hours, it showed an opposite rota- 

 tj,„, ,,f —!).<)'.§ riuene heated to 250° to oOO"^ is converted into dipenteiu' C,„H„„ l)oiling at 175°^ 

 and a hyilrocarbon CioH,., l)oiling at 2()(l'^ C. 



These illustrations will suttico to show that the transformation of pinene into isomeric and 

 heavier hydrocarbons may occur, at least partially, after the turpentine has been removed from 

 the tree. 



The crude turpentine from Fiiiun palustrh, or hnig-leaf pine, is thus made up of — 



(1) Rosin, 7.5 to 'JO per cent ; mostly abietic anliy<lride. 



(2) Aiistralene, 2.5 to 10 per cent; boils at 1.55 to 1.56° C. 



(S) Some othiT terpenes of CiiiHit,; small portions; kind not known. 



(4) .Some polyterpenes of (CsHs),, ; small portions; kind not known. 



(5) Cymene ( ?) CioHu; small portions, if any ; boils at 175 to 176" C. 



(6) Traces of formic anil acetic acids; produced probably by atluospheric oxidation dnrinj; collection of tur- 

 pentine. 



'Allen, Com. Ilry. Anal, 2, 437. t Allen, Cnm. tlifl. JnnL, 2, 441. 



XJoiir. Amd. and A2)pL Chem., 6, 5 \^ Muspratt's Cbemie, 4th ed., 1, 153 



