— 45 — 



acid, yielded principally isobornylacetate, b. p. 70 to 71° (3 to 4 mm.), 

 which upon saponification invariably gave rise to borneol-free isoborneol, 

 m. p. 212°. Similarly, when separate fractions were saturated with hydro- 

 chloric acid gas, the principal resulting product was invariably the well- 

 known camphene hydrochloride, m. p. about 148°. In spite of these re- 

 sults, however, we must continue to assume that the camphene-yielding 

 fractions of citronella oil also contain considerable proportions of another 

 terpene, perhaps an isomeric camphene, which eventually, in the case of 

 some of the reactions above referred to, is converted into derivatives of 

 ordinary camphene. It should further be stated that when a fraction 

 <di 5 o 0,8636; « D — 67°46'; n D20 o 1,47009) was oxidised with alkaline per- 

 manganate under ice-cooling, there occurred besides camphene camphoric 

 acid, traces of an acid melting at 180°, which was not identical with suc- 

 cinic acid. 



Attempts to establish the presence of phellandrene in a fraction 

 boiling between 170 and 175° (d 15 o 0,8490; « D — 57° 14') and of sylvestrene 

 in fractions boiling between 180 to 182° and 182 to 186° respectively, 

 only yielded negative results. On the other hand, dipentene was found 

 in all the fractions, and one of them also afforded Z-limonene. The tetra- 

 bromides of both terpenes gave the characteristic melting points after 

 fractional crystallisation, and the limonene was furthermore identified from 

 the nitrolbenzyl derivative, m. p. 92 to 93°. The above-mentioned fraction 

 boiling between 170 and 175° was also tested for p-cymene, and for this 

 purpose was treated with 1 °/o permanganate. The oil which was not 

 attacked, when driven over with steam, had an odour of cymene, but 

 it also possessed a marked optical activity (« D + 61°10') and when 

 further oxidised under heat it yielded no ^-hydroxy^sopropyl benzoic 

 acid. In order to test for terpinene, the fractions boiling above 175° 

 were saturated in a solution of glacial acetic acid and ether with 

 hydrochloric acid gas and also with permanganate in the presence of 

 alkali, according to Wallach's method. The former reaction gave a hydro- 

 chloride, m. p. 49 to 50°, from which after heating with aniline a hydro- 

 carbon was regenerated which, after distillation over sodium, possessed 

 the following constants: b. p. 180 to 182°, d 15 o 0,8544, « D — 0°3', 

 n D 2oo 1,47821. This hydrocarbon yielded no nitrosite, but when brominated 

 in chloroform solution it afforded a bromide, m. p. about 123°; and is 

 therefore identical with dipentene. The permanganate oxidation-product, 

 ^i syrup, could not be distilled in vacuo without decomposition. The crude 

 product showed no inclination to crystallise. Hence it is probable that 

 citronella oil does not contain terpinene. 



The interesting discovery was made that after repeated fractionation 

 it was possible to isolate from the portions containing dipentene terpene- 

 mixtures of a very low sp. gr. These mixtures had a peculiar, estragon- 

 like odour and pointed to the presence of a new terpene. Unfortunately 



