DESTRUCTIVE DISTILLATION OF MANILA COPAL. 205 



The products which are given off by the fused resin up to 330° are 

 resin oil, pinene, (3 pinene, limonene, dipentene, camphene, water, formic 

 acid, acetic acid, methyl alcohol, acetone,, acetyl . formaldehyde, formal- 

 dehyde, furfur aldehyde, carbon dioxide, saturated and unsaturated hydro- 

 carbons, and probably acrolein. 



THE TERPENES CONTAINED IN MANILA COPAL. 



The weight of oil obtained from 1,500 grams of small pieces was 9-i 

 grams, of which about 1 cubic centimeter boiled below 150°. About 

 24 grams of the oil boiled between 150° and 178°, but the greater part 

 of the fraction passed over between 170° and 178°. Owing to the small 

 quantity of the lower boiling portion, a thorough study of it was not made. 



The presence of limonene in the fraction boiling between 170° and 



178° was shown by isolating limonene tetrabromide, a good yield being 



30° 

 obtained. The oil showed an optical rotation of A-^~=58°.50. The 



low optical rotation is indicative of dipentene, but after several fractional 

 crystallizations of the limonene tetrabromide the melting point, 104°, 

 was unchanged. The crystals were dextrorotatory. Limonene nitrosyl 

 chloride was prepared from this fraction and identified microscopically. 9 

 Crystals of pinene nitrosyl chloride were identified in the same manner 

 in the lower boiling fraction. 



Limonene does not commonly occur in coniferous resins although it is found, 

 accompanied by pinene, in pine needles. I limonene is obtained commercially from 

 the needles of Abies alba Miller. Recently Herty and Dickson 10 found I limonene 

 to be the principal volatile oil in the oleoresin of Pinus serotina Michx. 



The presence of pinene in Manila copal Avas first noted by Mr. G-. F. 

 Richmond, 11 who obtained it by distillation with steam. The volatile 

 oil from certain specimens of Manila copal appears to consist almost 

 entirely of pinene, while others show a high percentage of limonene. 

 The presence of limonene could not be proved in the distillates from 

 certain samples, and if present, it exists there in very small amount. 



As would be expected, individual pieces of the resin vary in the per- 

 centage of volatile oils contained in them. It would probably be safe 

 to assume that the soft, white resin, from which about 11 per cent of 

 terpenes was obtained, is of comparatively recent origin; while the 

 hard, brown resin containing less volatile oil is much older. In general, 

 very large lumps contain more volatile oil than small pieces. Large 

 pieces which were quite hard on the surface and had a much weathered 

 appearance were found to yield as high as 6 per cent of terpenes. The 



9 Chace, Jotim. Am. Chem. Soc. (1908), 30, 1475. 

 w Journ. Am. Chem. Soc. (1908), 30, 872. 

 "This Journal, Sec. A (1910), 5, 185. 



