Description

Tanning spend acid introduces 】 tanning spend the acid, it is gallic acid dimer derivatives, is a kind of polyphenols two lactone. It can not only to free form existence, and more on condensation forms (such as tanning flowers, such as a nucleoside tannins) exist in nature. Tanning spend acid and chloride-ferric chloride of color reaction is blue, encounter sulfuric acid yellow, Greiss-meger positive reaction, but also easy and metal cation such as ca2, M combined. Pure tanning spend acid is a kind of yellow needle crystal, melting point (pyridine) more than **0 *2, slightly soluble in water, alcohol, soluble in alkali, pyridine, insoluble in ether. The molecular formula 】 C*4H6O8 The molecular weight 】 **8.*5