Because of their petroleum-like odor, the fruits of Pittosporum resiniferum, Hemsl., a tree that is widely distributed throughout the Philippines, are known as petroleum nuts. Even the green, fresh fruits burn with a bright flame if touched with a burning match. An investigation of the petroleum nuts by R. F. Bacon2) revealed the presence of heptane and of a dihydroterpene. Subjected to pressure, 1 kg. of fresh nuts yielded 52 g. of oil and the residue, when ground and expressed a second time, 16 g. of additional oil with the following properties: d 0,883; nD30o1,4577; other optical constants could not be determined. The oil was quite sticky and, when exposed in a thin layer, resinified rapidly.
1) Journ. chem. Soc. 89 (1906), 1083.
2) Philippine Journ. of Sc. 4 (1909), A, 115.
Ignited in an open dish it burned with a sooty flame. Up to 165° it distilled without decomposition. Above that temperature decomposition set in and a resinous oil passed over.
The lowest fraction boiled between 97 and 101°. Shaken with concentrated sulphuric acid and distilled over sodium, the oil had the following constants: d30/4o0,6752; aD + 0°; nD30o1,3840. Bromination of this fraction, which had the odor of diphenyl methane and which doubtless is heptane, yielded /7-heptyl bromide. It boiled between 178 and 181° (93 under 70 mm. pressure) and, when heated with fused sodium acetate and acetic acid, yielded n-heptyl acetate, b. p. 192°.
The terpene fraction 150 to 160° after having been distilled three times over sodium, finally boiled between 158 and 160°: d30/4o0,8252; aD30o(+?)29,6o; nD30o1,4587. The liquid hydrochloride had the following properties: b. p. 114 to 116° under 34 mm. pressure; d30/4o0,9343; aD30o+ 9°; nD30o1,4655. When acted upon with magnesium and subsequently with water, a hydrocarbon with the following properties was obtained: b. p. 168 to 170°; d30/4o0,8050; aD30o +1,1°; nD30o1,4460. From these data the conclusion was drawn that the hydrocarbon in question was hexa-hydro-p-cymene. Hence the hydrocarbon in the original oil was a dihydroterpene. As is the case with limonene and phellan-drene, the chloride when treated with magnesium and benz-aldehyde yielded a hydrocarbon with two additional hydrogen atoms. Benzoin also was formed.