ELECTROCHEMICAL STUDY OF INTERACTION OF THE HEAVY METAL IONS IN HYDROXYLATION REACTION OF SALICYLIC ACID ON GLASSY CARBON ELECTRODEAbstract
The formation of free hydroxyl radical (˙OH) in oxygen transfers at GCE and the reaction between the electrochemically produced ˙OH and salicylic acid (SA) is studied by cyclic voltammetry method. Experiments showed that ˙OH is formed in the potential range of 1.0-1.4V corresponding to the anodic discharge of H2O at the GCE. The interaction of Cu2+, Hg2+, Cd2+, Mn2+ ions on the hydroxylation reaction is studied. The interaction of these metal ions is explained by using derived parameters such as surface coverage, formal potential, transfer co-efficient number and rate constant. The diffusion coefficient values for electroactive species on GCE is determined by using chronoamperomety and chronocoulometry techniques. It shows that Mn-SA has higher diffusion coefficient value as compared to the other systems. Multisweep cycle experiment on GCE surface provided mechanism for the reaction of hydroxylation on salicylic acid. This experiment suggests that metal ions first undergo Fenton-type hydroxylation reaction on salicylic acid and then undergo complexation reaction with 2, 5-dihydroxybenzoic acid.
B. Marichamy, A. Firose and N. Ramalakshmi*
Post-Graduate and Research Department of Chemistry, Presidency College, Chennai-05, Tamil Nadu, India
17 January, 2014
17 March, 2014
05 May, 2014
01 July, 2014