CONSTITUTION OF NEW ELECTROCHEMICAL SYSTEM USING A HYDROGEN STORAGE METAL (ALLOY) AND THREE-DIMENSIONAL EXPANSION OF THE REACTION FIELD

我们已经成功地建立了用Pd或储氢合金片电极对苯乙烯进行连续电化学加氢的体系。本研究将电化学加氢体系应用于其他不饱和有机或无机化合物，考察了反应场的三维扩展对加氢速率和反应选择性的影响。本研究两年来取得的成果总结如下：1.各种含C=C，(C=0或N=N)键的不饱和有机或无机化合物的加氢反应相继用我们的电化学加氢体系进行，加氢速率受双键性质和底物分子的影响。这有力地表明，电化学加氢体系适用于所有不饱和有机或无机化合物。该体系对4-甲基苯乙烯和2-辛烯的加氢速率随着Pd片电极加氢侧Pd黑色沉积量的增加而提高约50倍。这归因于反应场的三维扩展。通过在Pd片电极上修饰少量的铂或金沉积，也显著提高了加氢速率。铂、金、铜或镍沉积在钯或钯电极上后，CO_2和NO_3离子的还原速率显著提高，反应选择性的出现与沉积金属的性质有关。

We have already succeeded in constitution of successive electrochemical hydrogenation system of styrene using Pd or hydrogen storage alloy sheet electrodes. In the present study, the electrochemical hydrogenation system was applied to the other unsaturated organic or inorganic compounds, and effect of three-dimensional expansion of the reaction field on the hydrogenation rate and reaction selectivity were investigated. The results obtained in this study for two years are summarized as follows.1. Hydrogenation of various unsaturated organic or inorganic compounds with C=C, (C=0 or N=N bond successively proceeded using our electrochemical hydrogenation system, and the hydrogenation rate was influenced by the nature of double bond and substrate molecule. This strongly indicates that the electrochemical hydrogenation system is applicable to all unsaturated organic or inorganic compounds.2. The hydrogenation rate of 4-methylstyrene and 2-octene using this system increased up to around fifty times with the amount of Pd black deposits on the hydrogenation side of a Pd sheet electrode. This is ascribed to the three-dimensional expansion of the reaction field. The hydrogenation rate was also increased markedly by modifying small amount of Pt or Au deposits on the Pd sheet electrode.3. The deposition of Pt, Au, Cu or Ni on the Pd or palladized Pd sheet electrode led to the remarkable increase in the reduction rate of CO_2 and NO_3 ions and the appearance of the reaction selectivity depending on the nature of the deposited metals.