CTAB Reverse Micelles as Catalysts for the Oxidation of Ascorbic Acid by K3[Fe(CN)6]

K. Bhargavi (Department of Physical and Nuclear Chemistry and Chemical Oceanography, School of Chemistry, Andhra University, Visakhapatnam, AP)
P. Shyamala (Department of Physical and Nuclear Chemistry and Chemical Oceanography, School of Chemistry, Andhra University, Visakhapatnam, AP)
P S S Chakravarthi (Department of Physical and Nuclear Chemistry and Chemical Oceanography, School of Chemistry, Andhra University, Visakhapatnam, AP)
K V Nagalakshmi (Department of Chemistry, Gayathri Vidya Parishad College of Engineering (Autonomous), Madhurawada, Visakhapatna, AP)

Bulletin of Chemical Reaction Engineering & Catalysis
2022: BCREC Volume 17 Issue 1 Year 2022 (March 2022)

The oxidation of ascorbic acid by K3[Fe(CN)6] was studied in reverse micellar systems composed of CTAB (Cetyltrimethylammonium bromide), and it was found  the observed first order  (k1(aq) = 5.2×10−5 s−1, k1(rev) = 61.4×10−4 s−1) rate constant in reverse micellar medium is around forty times higher compared to aqueous medium under identical conditions. The rate enhancement (k2(aq) = 0.9×10−5 mole−1.dm3.sec−1, k2(rev) = 1.75×10−3 mole−1.dm3.sec−1)  is attributed to the large concentration effect and lower dielectric constant in the reverse micelles. The rate of the reaction increases with increase in W = {[H2O]/[surfactant]} which is explained in terms of ionic strength of the water pool. The effect of surfactant concentration on rate was explained on the basis of Berezin pseudo phase model. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).