Manila copal, derived from Agathis alba, Lam.:5) yields its volatile oil but difficultly to direct distillation with water vapor. A more complete separation can be accomplished by first neutralizing the resin acids with alkali, as was done by A. Tschirch and M. Koch4). From soft Manila copal these investigators obtained 6 p. c, from hard copal 5 p. c. of oil. From material of varying degrees of hardness, G. F. Richmond5) obtained yields that varied from 1,3 to 11,2 p. c. He obtained a lemon-yellow oil of a pleasant odor characterized by the following properties: d150/40 0,865; aD800 - 26,55°; nD30o 1,4648. The bulk of the oil boiled between 155 and 165° and contained a-pinene (hydrochloride, m. p. 124°).
Brooks5) has examined a copal oil which was not obtained by steam distillation but by dry distillation with a yield of about 6 p.c. The following constituents were identified: d-limonene (tetrabromide, m.p. 104°), d-a-pinene (nitrolbenzylamine, m.p. 122 to 123°), J-pinene (nopinic acid, m. p. 124 to 125°) and camphene (characterized by its conversion into /soborneol). From the low optical rotation of the limonene, the author infers the presence of dipentene.
1) Chem. Ztg. 29 (1905), 955.
2) A. Tschirch and M. Koch, Arch, der Pharm. 240 (1902), 228, footnote.
3) Philippine Journ. of Sc. 5 (1910), A, 185.
4) Arch, der Pharm. 240 (1902), 202.
5) Philippine Journ. of Sc. 5 (1910), A. 203. For the products resulting upon the dry distillation of Manila copal, compare also Tschirch and Koch loc. cit. also L Schmolling, Chem. Ztg. 29 (1905), 955.