N-Arylation Of Bromamine Acid Assisted By Electrochemical Method

N-Arylation reaction of bromamine acid (BAA) which has made great progress was well used in dye industry due to its significance. While, The catalyst had poor stability in water and the pollution of heavy metal as reducing agent was serious. Researchers had been looking for a green and efficient method to catalyze the reaction.The idea of electrocatalytic N-arylation reaction of BAA was introduced. The kinetics of N-arylation of BAA was studied to find factors for using electrochemical method. The coupling of BAA with N-acetyl-1,3-phenylenediamine (NAAA) was chosen as the model reaction to measure the reaction order of reactants with the result that NAAA was second-order and BAA was first-order. c-1-t curves at 75?,80?,85? and 90? showed the reaction rate coefficients of 706.2 L2mol-2h-1,1520.7 L2mol-2h-1,3049.7 L2mol-2h-1, and 6715.3L2mol-2h-1 which conformed to the Van't Hoff Rule. The ln{kA}-T-1 curve showed the activation energy of 156.65 kJ mol-1.Electron provided by noble electrode and a divalent copper complex were used as the catalytic system for the N-arylation reaction of BAA. The coupling of BAA with arylamines which have different solubility was chosen as the model reaction to select solvent. It showed that water which could dissolve the reactants and provide hydrion was the best solvent. Cyclic voltammetry was used to select the best one from twelve ligands. Because of the steric hindrance preventing the contact of Cu2+ with electrode, L1-L8 didn't have reduction peaks. On the contrary, reduction peaks of Cu-L9, Cu-L10, Cu-L11 and Cu-L12 appeared at potentials of -0.6 V,-0.8 V,-0.6 V and -0.1 V. Linear sweep voltammetry was used to select the best complex from four complexes mentioned above. Reduction peaks appeared again in potential range of -0.45 V--0.63 V,-0.6 V--0.9 V,-0.3 V--0.5 V and 0--0.3 V. Cu-L12 which could be reduced to Cu? in potential range from 0 to -0.3 V showed the best catalytic effect. Amperometric i-t curve was used to select the reduction potential of Cu-L12 using platinum mesh electrode, platinum plate electrode and saturated calomel electrode as the working electrode, the counter electrode and the reference electrode. The potential at -0.15V matched well with the reduction potential of Cu??Cu? with yield of 75.39%.