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Updated: May 24, 2026

Ethylene Polymerizations Using Parallel Pressure Reactors and a Kinetic Analysis of Chain Transfer Polymerization
Published on: November 27, 2015
Micelle-catalyzed reaction between ninhydrin and nickel dipeptide complex [Ni(II)-Gly-Tyr]+
Mohd Akram1, Dileep Kumar, Kabir-ud-Din
1Department of Chemistry, Aligarh Muslim University, Aligarh, UP, India. drmohdakram@rediffmail.com
Abstract:
The interaction of nickel dipeptide complex [Ni(II)-Gly-Tyr](+) with ninhydrin has been investigated in the absence and presence of cationic cetyltrimethylammonium bromide (CTAB) and gemini (16-s-16, s=4, 5, 6) surfactants spectrophotometrically at 80°C and pH 5.0. The product formed was the same and the reaction followed first- and fractional-order kinetics with respect to [Ni(II)-Gly-Tyr](+) and [ninhydrin], respectively, in both aqueous as well as micellar media. In the presence of CTAB, rate increased and reached up to a maximum, then decreased. Also, whereas typical rate constant (k(Ψ)) increase and leveling-off regions, just like CTAB, were observed with geminis, the latter produced a third region of increasing k(Ψ) at higher concentrations. This unusual third-region effect of the gemini micelles is assigned to changes in their micellar morphologies. The micellar catalysis is explained in terms of pseudo-phase model. The binding constants and the values of activation parameters such as activation energy (E(a)), enthalpy of activation (ΔH(#)) and entropy of activation (ΔS(#)) have been evaluated.
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