铂和铜电极上4-硝基吡啶-1-氧化物还原过程研究

4-氨基吡啶是一种重要的精细化工产品, 为探讨其电化学合成过程的反应机理, 采用循环伏安法、库仑电解等方法对强酸性条件下4-硝基吡啶-1-氧化物的电化学行为进行了研究. 结果表明: 4-硝基吡啶-1-氧化物在铂电极上主要经历电化学-化学-电化学(ECE)还原历程, 并生成4-羟胺吡啶-1-氧化物; 对铜电极而言, 当电位高于－0.65 V时主要经历ECE还原历程, 并生成4-羟胺吡啶-1-氧化物; 当电位低于－0.85 V时经历ECE还原历程生成的4-羟胺吡啶-1-氧化物, 可发生进一步4e^－还原, 并生成4-氨基吡啶.

Reduction Performance of 4-Nitropyridine-1-oxide on the Electrodes of Platinum and Copper

4-Aminopyridine is an important fine chemical. To investigate the electrochemical synthesis mechanism of the 4-aminopyridine, the electrochemical behavior of 4-nitropyridine-1-oxide under the strong acid conditions was studied by cyclic voltammetry, controlled potential coulometry and some other methods. 4-Hydroxylaminopyridine-1-oxide was produced when 4-nitropyridine-1-oxide mainly went through the electrochemical-chemical-electrochemical (ECE) process on the platinum electrode. As far as the copper electrode was used, the potential should be higher than -0.65 V to go through the ECE process, and 4-hydroxylaminopyridine-1-oxide was produced. When the electrode potential was lower than -0.85 V, 4-hydroxylaminopyridine-1-oxide could be reduced further to 4-aminopyridine after another 4e- transfer on the copper electrode.