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Kinetic Model for Reactivity in Quaternary Water‐in‐Oil Microemulsions
Author(s) -
GarcíaRío Luis,
Hervella Pablo
Publication year - 2006
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200600091
Subject(s) - microemulsion , chemistry , alcohol , hexanol , molar volume , reactivity (psychology) , pulmonary surfactant , octanol , bromide , volume (thermodynamics) , benzyl alcohol , organic chemistry , inorganic chemistry , thermodynamics , partition coefficient , catalysis , medicine , biochemistry , physics , alternative medicine , pathology
Abstract A study was carried out on the nitrosation of piperazine (PIP) and N ‐methylbenzylamine (MeBzAm) by N ‐methyl‐ N ‐nitroso‐ p ‐toluenesulfonamide (MNTS) in quaternary microemulsions of tetradecyltrimethylammonium bromide (TTABr)/isooctane/alcohol/water, varying the nature and the concentration of the following alcohols: 1‐pentanol, 1‐hexanol, 1‐heptanol, 1‐octanol and 1‐decanol keeping the [1‐alcohol]/[TTABr] = 4 relationship constant. In addition a study was carried out on the influence of the alcohol concentration, working with molar relationships [1‐hexanol]/[TTABr]=3, 4 and 5. On the basis of the molar volumes of the alcohol and surfactant and the concentration of alcohol at the interface it was possible to calculate the change in its volume with as varying compositions of the microemulsion. In order to interpret the experimental results a kinetic model was devised which takes into account the distribution of the reactants between the different pseudophases and the change in the volume of the interface. The rate constants at the interface of the microemulsion are lower than in pure water and are independent of the nature of the alcohol used as a cosurfactant and the molar relationship [alcohol]/[TTABr]. This independence indicates that the main role of the cosurfactant is to increase the volume of the interface with the consequent dilution of the reactants.