High Stability organic tanning using plant polyphenols. Part 2. The mechanism of the vegetable tannin-oxazolidine Tannage.

摘要

Catechin was used as a model for condensed vegetable tannins, to elucidate the reaction between the flavonoid ring system and oxazolidines in the combination tannage. Using H-NMR, C-NMR and paper chromatography, it is shown that the crosslinking reaction occurs predominantly at the C-6 and c-8 of the phloroglucinol A ring of catechin. The crosslinker reacts at the C-5 of oxazolidine, by ring opening and racting via the N-methylol intermediate.