不饱和醇电还原的质谱-电化学循环伏安(MSCV)法研究 Ⅰ.烯丙醇的电还原

MSCV Studies of Electroreduction of Unsaturated Alcohols Ⅰ. Electroreduction of Allyl Alcohol

用MSCV法研究了烯丙醇在多孔Pt电极上0.5mol·dm^(-3)KClO_4中的电还原.烯丙醇电还原时主要涉及二类反应:烯丙基上C—OH断键生成丙烯;丙烯进一步氢化生成丙烷.表征丙烯及丙烷的诸碎片m/z的质谱电流(I_M)-电极电位(φ)扫描曲线详细描绘了各分步反应的状况.在一定电位范围,各m/z的IgI_M-φ呈线性;求得各有关m/z的Tafel斜率.根据实验结果对反应机理进得了详细分析.

Results from MSCV (Mass Spectrometric Cyclic Voltammetry) studies for electroreduction of propargyl alcohol at Pt porous electrodes in 0.5mol·dm^(-3) HClO_4 indicate that C—OH bond may be cleaved in both allyl and propargyl groups, followed by forming propene and propane. Besides,a small amount of propargyl alcohol is directly protonated to allyl alcohol. The mass current (I_M)-potential (φ) relationship of the fragments provide detailed information for the constituent reactions. For all the m/z values studied, the logI_M-φ relations exhibit a linear range and their Tafel slops were obtained. Possible mechanisms are discussed based on the experimental results.