Hydrolysis of p‐Nitrophenyl Picolinate Catalyzed by Gemini Surfactants with Different Hydrophobic Tail Groups

Abstract

Hydrolysis of p‐nitrophenyl picolinate (PNPP) mediated by the micellar catalytic systems of two gemini cationic surfactants with different hydrophobic tail groups (ethanediyl‐1,2‐bis(dodecyldimethylammonium bromide) (12‐2‐12, 2Br⁻), dimethylene‐1,2‐bis(cetyltrimethyl‐ammonium bromide) (16‐2‐16, 2Br⁻)) was investigated spectrophotometrically in the pH range of 7.0–9.0 and at 25°C. It is noteworthy that (1) two gemini surfactants showed catalytic effects on the hydrolysis of PNPP and gemini surfactant (16‐2‐16, 2Br⁻) enhanced the hydrolytic reaction notably more than gemini surfactant (12‐2‐12, 2Br⁻) micellar solutions under the same reaction conditions, which may be ascribed to the micelle effect and (2) the apparent rate constants (k _obsd) of PNPP hydrolyses increased with increasing pH values of the reaction media.

Keywords:

• Hydrolysis of PNPP
• gemini cationic surfactants
• hydrophobic effect
• microviscosity effect

Acknowledgments

This work was supported by National Natural Science Foundation of China (Grant: 20173038 and 20107004).