【摘要】 N-甲基羟胺及其盐酸盐广泛应用于医药和农药中间体的合成,以及核废料处理与回收等领域。采用线性扫描和循环伏安方法,研究了硝基甲烷电还原一步制备N-甲基羟胺及其盐酸盐的反应特性。在盐酸溶液中,硝基甲烷在铜、铜汞齐和镍电极上均具有明显的还原活性,其活性大小依次为铜>铜汞齐>镍>石墨,其中硝基甲烷在铜电极上的还原电位为?0.65~?0.75V(vs.SCE)。电解合成试验结果表明,采用铜和铜汞齐作为阴极材料,电合成N-甲基羟胺盐酸盐的电流效率均超过90%,产品收率超过86%;采用镍和石墨作阴极,电流效率和产品收率均较低。其中铜电极在1200~2500A?m?2的电流密度范围内,电解时间为理论电解时间的80%时,具有最好的电流效率。与传统的催化氢化法合成N-甲基羟胺比较,电化学还原硝基甲烷制备N-甲基羟胺盐反应条件温和、污染少、成本低,是一种非常有效的合成新方法。更多还原

【Abstract】 N-methylhydroxylamine and its HCl salts have been extensively used in the synthesis of pharmaceutical and pesticide intermediate, and the reprocessing of nuclear waste etc. In this paper, the electrochemical reduction characterizations of nitromethane to form N-methylhydroxylamine on Cu, amalgamation Cu(Cu-Hg), nickel and graphite electrodes in HCl solutions were investigated respectively. The excellent electroreduction activity of nitromethane were observed on Cu, Cu/Hg and nickel electrodes except graphite electrode, and the order of activity is Cu>Cu-Hg>Ni>C(graphite). The reduction of nitromethane on Cu electrode is in the potential range of ?0.65~ ?0.75V (vs.SCE). The results of the eletrosynthesis experiments show that using Cu and Cu-Hg as the cathode, the electrolysis efficiency is > 90% and the product yield is > 86%, whereas when using nickel or graphite as the cathode, the current efficiency and product yields are relatively low. The highest current efficiency may be obtained when the electrolysis time is about 80% of the theoretical time and the current density is in the range of 1200~2500 A?m?2. Compared with the traditional catalytic hydrogenation synthesis methods, electrosynthesis of N-methylhydroxylamine is a new efficient production method due to its simplicity, low costs and little pollution.更多还原