Micellar Catalysis of p‐Nitrophenyl Picolinate with Ternary Complexes

Abstract

A general quantitative treatment of catalytic reactions involving metal (M) ligand (L) complexes where S is the substrate (M _m L _n S) is proposed in this paper. The thermodynamic and kinetic parameters of the reactions can be obtained through this treatment. Applying this method to the hydrolysis of p‐nitrophenyl picolinate (PNPP) catalyzed by Ni²⁺, Zn²⁺, Co²⁺ complexes at pH 7.00 and 30°C, we have obtained thermodynamic and kinetic parameters in the presence and absence of cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), and Brij35 surfactants. The results indicate that the activated hydroxyl group of the ligand is an effective nucleophilic species in the hydrolysis of PNPP, and CTAB, SDS, Brij35 surfactant micelles dramatically inhibit the hydrolysis of PNPP. The activity of the metal ion catalysts decreases in the order of Ni²⁺ > Zn²⁺ > Co²⁺.

Keywords:

• N‐Methyl diethanolamine
• Metal complexes
• Catalytic hydrolysis
• Surfactant
• Micelles

Acknowledgment

Projects 01GY051‐63 and 01LA52 were supported by the Science and Technology Department and Education Department of Sichuan Province.