Electro-oxidation of phenol in acid and neutral media

Phenolic compounds are the major pollutants in waste water from coal and petroleum industries and their concentratlons even go up to 7000 ppm. Treatment of such waste water has been a problem so long, since the tolerance limit for disposal is 1 pprn phenol. Investigations are carried oyt on the anodic oxidation of phenol at graphite electrode in acid and sodium chloride media using various electrochemical techniques such as linear sweep voltammetry, cyclic voltammetry and controlled potential electrolysis. The extent of oxidation was determined by electrolysis at controlled potential of + 0.98 V which corresponds to final oxidation peak. In acid medium the peak heights varied quantitatively with concentration of phenol. There is a scope of using linear sweep voltammetry as an analytical method for the estimation of phenol in acid mediu

On the electrochemical behaviour of nicotinamide

Most of the biological interest in pyridine derivatives centres around nicotinamide which is the building block for the coenzymes, Nicotinamide adenine dinucleotide (NAD). Except for some polarographic studies, not many references are available on the electrochemical behaviour of nicotinamide. In the present investigation, the reduction of nicotinamide has been studied in non aqueous medium using glassy carbon electrode, in the solvent dimethyl formamide (DMF). Investigations have been carried out in the potential range +400 mV to -2400 mV at different scan rates using tetra alkyl ammonium perchlorates as the supporting electrolyte. Two cathodic peaks are observed around -1.6 V and -1.9 V, Depending upon the alkyl group used in the supporting electrolyte, the peak potentials are slightly varied. A small broad oxidation peak was observed on the reverse scan. From the value of peak currents, the value of n was determined to be one for each peak. Nicotinamide was found to get reduced in the ring yielding 1,4-di hydronicotinamid

Electrochemical reduction of alloxan monohydrate on HMDE

Alloxan monohydrate (AM) is a fully oxygenated pyrimidine and has been the subject of intensive study owing to its importance in biological systems. The hydrated carbonyl group in the 5th position is known to be active functional group. The electrochemical reduction of AM has been investigated by cyclic voltammetric technique using HMDE at pH 1.0 to 5.0 using acetate buffer. The range of potential scan employed was from +200 mV to -1.5V vs SCE and the scan rate was varied from 10 mV.s^-1 to 640 mV.s^-1 and the experiments were carried out in nitrogen atmosphere. Two reduction peaks PCI and PCII were observed around 40 mV-200 mV and around -850 mV to -900 mV vs SCE depending upon the pH. On the anodic side also two peaks were observed. All the peaks were dependent on pH and scan rate. At low pH, PCI was a plateau while PaI was absent. The reduction reaction was found to occur in two stages, namely, dehydration of AM followed by its reduction to dialuric acid at low pH, whereas at high pH this two stage reduction and reduction of dehydrated alloxan compete with each other. The product formed was confirmed by U.V. & I.R