Patent ID: 8795390

Claim:
A process for the production of tanned leather, skin or pelt by non-metal tanning, comprising the step of tanning a bated hide, skin or pelt with a tanning agent (A), the tanning agent (A) being at least one compound of formula (I), wherein Hal is chlorine or fluorine, X is N or CR Y is hydrogen, C 1-8 -alkyl, C 1-4 -alkyl-carbonyl, C 1-4 -alkyl-sulphonyl or a radical of formula (Ia), or (Ib) —(—C 2-3 alkylene-O—) q —H (Ib) R is hydrogen or chlorine, q is 1 to 10 and M is hydrogen, an alkali metal cation or an ammonium cation, the ammonium cation being a protonated tertiary amine or a quaternary ammonium cation, in a tanning bath, the tanning bath having a pH of from 6 to 10 at the beginning of the tanning step.