THE ROLE OF IODINE AND PYRIDINE BASES IN THE ELECTROCATALYTIC OXIDATION OF ALCOHOLS MEDIATED BY 4-AcNH-TEMPO

The role of iodine, pyridine bases and nitroxyl radical (NR) - 4-AcNH-TEMPO in the electro oxidative transformation of alcohols to carbonyl compounds in a two-phase environment CH2Cl2/NaHCO3 (aq.) has been studied. Using the CV method, it was established that the iodide ion in a weakly alkaline medium (pH 8.6) is oxidized to active forms of iodine (I2 and I+), which are terminal oxidizers for NR capable ofbeing converted into oxoammonium cations (ОС), necessary for the oxidation of alcohol. Spectrophotometrically it has been established that pyridine bases are capable of stabilizing I2 and/or I+ in the form of [PyI2], [PyI]+ complexes, the formation of which occurs predominantly in the organic phase. Stabilized forms of iodine effectively convert NR into OC at the interface. The formation of a catalytic complex between ОС and a pyridine base occurs in the aqueous phase. CV studies have shown that the rate of NR-mediated alcohol oxidation increases up to 4 times in the presence of a pyridine base, in contrast to the oxidative transformation without a pyridine base. This proves the advantages of the NR/pyridine base catalytic system and the role of the pyridine base as a promoter in the inderect electrooxidation of alcohols.