Description

Maracaibo copaiba is a clear, viscous, brownish-yellow liquid with a slight but distinct green fluorescence. It possesses a characteristic aromatic odour and an unpleasant, acrid and rather bitter taste. It is miscible in all proportions with chloroform, carbon disulphide, and benzene, and also with an equal volume of petroleum spirit, but with larger proportions of the latter a slight precipitation takes place; with absolute alcohol it behaves similarly. The specific gravity varies from 0.980 to 0.999, or even slightly higher. The proportion of volatile oil varies from 42 to 53 per cent.

Constituents

Maracaibo copaiba consists of a mixture of resin and volatile oil with which traces of a bitter principle and fluorescent substance are associated.

The volatile oil is invariably lsevorotatory, the rotation in 100 mm. tube varying from - 5° to - 35°, usually, however, it does not exceed - 25°; its specific gravity varies from 0.896 to 0.910 and its boiling-point from 250° to 275°; it does not respond to the test for gurjan balsam (see below). These details are important indications of the purity of the oleo-resin.

The resin contains a small proportion of copaivic acid (removed by ammonium carbonate from ethereal solution), but consists chiefly of β-metacopaivic acid (extracted by sodium carbonate after removal of the copaivic acid); with these there is associated a small quantity of two indifferent copaibo-resenes and of crystalline illurinic acid (compare African copaiba).

The bitter principle and fluorescent substance have not yet been obtained in a pure state.