Formation and decomposition of zinc cellulose xanthate in acid media

Complex formation between zinc (5 × 10^?2?5 × 10^?4M) and cellulose xanthate and its effect upon the rate of dexanthation by 0.25M sulfuric acid were studied. The determinations were based on spectrophotometric measurements on dilute solutions of cellulose xanthate with γ-numbers from 140 to 30. The results showed that the tendency of the xanthate groups to enter into complexes with zinc increased as the γ-number decreased. The stabilization toward decomposition by acid produced by complex formation was also found to vary with the γ-number and was much smaller at low than at high γ-numbers. These findings indicate that cellulose xanthate, because of local differences in the steric arrangement of potential ligand groups along the molecule, can form a whole set of zinc complexes, differing in thermodynamic stability and reactivity toward acid.