Study On Interaction Between The Zirconium Sulfate And Small Molecules Compounds Containing–COOH、-OH OR-NH₂

With the improvement of living standards and strengthening ofenvironmental protection consciousness, zirconium tanning as arepresentative of no chrome tanning metal started to be used in tanning orretanning process. Because of the complexity of the leather collagen itself, allkinds of uncertain factors during tanning process and so on, people knew themechanism of zirconium tanning fuzzily. Studying the tanning mechanismcould provide the theory basis for industrial production preferably, so we tookthe complex process of tanning simplified, doing a series of simulation toprovide the reference of the more clear understanding of zirconium tanningmechanism.Basing on our research of the interaction between the amino acid andzirconium sulfate, continued to choose zirconium sulfate（Zr（SO₄）₂·4H₂O） as arepresentative of zirconium tanning agent, Choosed dipeptide, amino acidmethyl ester hydrochloride, organic masking agent （lactic acid, acetic acid）,glycerin, ethanol amine and triethanolamine, this small molecules compoundsof carboxyl （-COOH）, hydroxyl （-OH） and amino （-NH₂） as a leather collagensimulation objects, studied their interaction by TLC detection, IR, NMR andXRD.The results of the reactions between zirconium sulfate and dipeptideindicated that: zirconium sulfate reacted with carboxylic group（-COOH） ofdipeptide, zirconium ions (Zr⁴⁺) and the carboxyl anion （-COO^-） formed ionicbond. At the same tame, because the special structure of dipeptide, zirconium ion (Zr⁴⁺) and the oxygen（O） of hydroxyl、the nitrogen（N） from amido bondformed five-membered ring chelatecompounds. Comparing with ionic, thiseffect was stronger, and made products being crystalline.The results of the reactions between zirconium sulfate and the otherseries small molecules containing carboxyl（-COOH）, hydroxyl（-OH） oramino（-NH₂） indicated that: with the hydroxyl（-OH） and carboxyl（-COOH）coexistence, zirconium ions (Zr⁴⁺) could reacte with them at the same time,and the productions could be dissolved in pH=6. Only the hydroxyl（-OH） orcarboxyl（-COOH）, zirconium ions (Zr⁴⁺) could also reacte with them, andform ionic bond; With the hydroxyl（-OH） and amino（-NH₂） coexistence,zirconium ions (Zr⁴⁺) could reacte with them, and improve the pH value ofreaction liquid to alkalinity. The solid of zirconium sulfate could be dissolveddirectly under the condition of the hydroxyl（-OH） and amino（-NH₂）coexistence.