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Study of the reaction of methyl 4‐nitrobenzenesulfonate and Br − in water–glycerol cationic micellar solutions
Author(s) -
Graciani María Del Mar,
Rodríguez Amalia,
Fernández Gaspar,
Muñoz María,
Moyá María luisa
Publication year - 2008
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.20359
Subject(s) - chemistry , cationic polymerization , bromide , micelle , glycerol , micellar solutions , reaction rate constant , solvent , pulmonary surfactant , micellar liquid chromatography , reaction rate , inorganic chemistry , kinetics , organic chemistry , catalysis , aqueous solution , biochemistry , physics , quantum mechanics
The reaction of methyl 4‐nitrobenzenesulfonate (MNB) and Br − has been studied in water–glycerol (GLY) alkyltrimethylammonium bromide micellar solutions, with the weight percentage of glycerol up to 50%. A pseudophase kinetic model was used for quantitatively discussing the kinetic data. Results showed that the equilibrium‐binding constant for the organic substrate molecules to the cationic micelles decreases upon increasing the amount of glycerol present in the micellar reaction media. The second‐order rate constant of the reaction in the micellar pseudophase is practically independent of wt% of GLY. Similar results were found in other water–organic solvent alkyltrimethylammonium bromide micellar solutions for the same process. However, the dependence of the reaction rate, for a given surfactant concentration, on the wt% of organic solvent is weaker for glycerol than for the other organic solvents. This was explained by considering that the cationic micellar ionization degree is nearly independent of wt% GLY. As a consequence, bromide ions concentration in the interfacial region (the reaction site) does not change by varying wt% of GLY. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 845–582, 2008