Kinoïn by heating it to 130° C. gives off water and turns red:
2 C₁₄H₁₂O₆ = OH₂ · C₂₈H₂₂O₁₁.
The latter product is an amorphous mass agreeing with kino-red; by heating it at 160-170° it again loses water, thus affording another anhydride.
Etti succeeded in preparing methylic chloride, pyrocatechin CH₄(OH)₂ as well as gallic acid C₇H₆O₅, by decomposing kinoïn.
We have prepared kinoïn from Australian kino ([see page 198]), but failed in obtaining it from Malabar kino, which however Etti states to have used. Kino affords about 1½ per cent. of kinoïn.
The solutions of kinoïn turn red on addition of ferric salts.
Commercial kino yielded us 1·3 per cent. of ash.
Commerce—The quantity of true kino collected in the Madras forests is comparatively small, probably not exceeding a ton or two annually. The drug is often shipped from Cochin.
Uses—Kino is administered as an astringent. It is said to be used in the manufacture of wines, and it might be employed if cheap enough in tanning and dyeing.
Other sorts of Kino.