Micellar Catalysis on 1,10-Phenanthroline Promoted Chromic Acid Oxidation of Propanol in Aqueous Media

EXPERIMENTAL

1, 10-phenanthroline (AR, Merck), propanol (AR, Qualigens), K2Cr2O7 (AR, BDH), sodium dodecyl sulphate (SDS) (AR, SRL), TX-100 (AR, SRL) and all other chemicals used were of highest degree of purity available commercially. All the solutions were prepared in double distilled water. Solutions of the oxidant and reaction mixtures containing the known quantities of the substrate(s) (i.e. propanol), promoter (1,10-phenanthroline) under the kinetic conditions [propanol]T>>[Cr(VI)]T acid and other necessary chemicals were separately thermostated (±0 ℃). The reaction was initiated by the requisite amounts of the oxidant with the reaction mixture. Progress of the reaction is monitored by following the rate of disappearance of Cr(VI). The concentration of Cr(VI) at different time intervals was measured by a titrimetric quenching technique using excess of standard Mohr’s solution and unreacted Fe(II) was estimated by a standard Ce(IV) solution using ferroin indicator.10a The pseudo first order rate constants were calculated from the slopes of the plot of log [Cr(VI)]t versus time t, which were linear at least for three half lives. The scanned spectra, spectrum after completion of the reaction and other spectra were recorded with a UV-VIS spectrophotometer [UV-1800 and UV-VIS NIR-3600 (SHIMADZU)]. Quartz cuvettes of path length 1 cm were used. Under the experimental conditions, the possibility of decomposition of the surfactants by Cr(VI) was investigated and the rate of decomposition in this path was kinetically negligible.