关键词：
catalysis;hydrolysis of PNPP;metal ion micelle
摘要：
Abstract Comparative reactivities of different metal ions in different micellar solutions (cationic, anionic, nonionic micelle) for the hydrolysis of p‐nitrophenyl picolinate (PNPP) were investigated spectrophotometrically at pH 7.0 and 25°C. The kinetics analysis was carried out by invoking a model of micellar catalysis. The results show that compared with metal ions in aqueous solution, cationic micelles inhibit metal ion catalyzed hydrolysis of PNPP, anionic micelles accelerate metal ion catalyzed hydrolysis of PNPP and nonionic micelles show no appreciable effect on metal ion catalyzed hydrolysis of PNPP. The higher the electron charge of metal ions, the greater these effects are, indicating electrostatic interactions are the major reason for metal ion catalyzed hydrolysis of PNPP in micellar solution.
期刊：
Journal of Dispersion Science and Technology,2003年24(6):755-760 ISSN：0193-2691
通讯作者：
Zeng, XC
作者机构：
[Zeng, XC] Sichuan Univ, Fac Chem, Chengdu 610064, Peoples R China.;Wuhan Polytech Coll, Dept Biol & Chem Engn, Wuhan, Hubei, Peoples R China.
通讯机构：
[Zeng, XC] S;Sichuan Univ, Fac Chem, Chengdu 610064, Peoples R China.
关键词：
Amine additives;Critical micelle concentration;Hydrogen bond interaction;Ionic surfactants
摘要：
This paper describes the effect of four types of amine (ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine) as polar additives on the critical micellar concentrations (CMCs) of ionic surfactants, [cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS)] in buffered solutions (I=0.1 M KN0<inf>3</inf>, 0.01 M Tris-TrisH<sup>+</sup>) at pH 7.00 ±0.01 by electrical conductivity. It was found that the CMCs of these surfactants all decreased with increasing amine concentrations and the extent of effect followed the sequence: tetraethylenepentamine >triethylenetetramine >diethylenetriamine >ethylenediamine. Based on these results, several empirical linear models were obtained. From the experimental data, it is apparent that the extent of decreasing CMCs of CTAB and SDS by the same amine is roughly similar, and this may be ascribed to the polarity of additives and hydrogen bond interactions.
