- The Reaction of Hematoxylin with Zirconyl Chloride Studied Spectrophotometrically
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The reaction of hematoxylin with zirconyl chloride in acid solutions was studied spectrophotometrically.A strong absorption band with λmax = 525 nm is attributed to a loose complex formed between hemateine and zirconium(IV) ions.The experimental findings - especially the fact that the linear absorption coefficient increases with time, passes through a maximum and then declines exponentially - are consistent with a four step mechanism.Two of the steps are fast equilibria, while the other two are slow dissociation reactions, the second being an order of magnitude faster than the first.The rate constants for the slow steps and the equillibrium constants for the fast steps have been determined.From the variation of these constants with temperature the activation parameters of the slow reactions and thermodynamic data for the fast equilibria have been calculated.Also the molar absorption coefficient of the absorbing complex has been estimated.Possible analytical applications of the reactions studied are briefly discussed. - Keywords: Zirconyl chloride, Hematoxylin complex formation rates, Activation parameters of complexes, Thermodynamic data of complexes
- Roubani-Kalantzopoulou, Fani,Katsanos, Nicholas A.
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p. 165 - 182
(2007/10/02)
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