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双葱酮的电化学还原是一个ECE过程.本文通过均相氧化还原催化作用研究此体系,以醌类作催化剂.测定了在DMF溶剂中氧化还原对A/A~7的标准电位E_(AA~7)~O=-1.166伏(相对于饱和甘汞电极),电子转移的速度常数k_(S,AA~7)~O=4.1×10~(-2)厘米·秒~(-1),构型转变速度常数k_(AD)~-=1.8×10~6秒~(-1),确定了电子转移过程A+e→A~7是双葸酮还原反应的速度控制步骤.还测定了溶液电子交换反应的标准速度常数logk_s~(sol)=7.04,并确定了在均相催化反应中,歧化机理是主要的.
The electrochemical reduction of bismulfurone is an ECE process.In this paper, the system was studied by homogeneous redox catalysis and quinone as catalyst.The redox potential of A / A ~ 7 standard E_ (AA ~ 7) ~ O = -1.166 V (relative to saturated calomel electrode), the electron transfer rate constant k_ (S, AA ~ 7) ~ O = 4.1 × 10 ~ (-2) cm ~ , The conformational transition rate constant k_ (AD) ~ - = 1.8 × 10 ~ 6sec ~ (-1), and the electron transfer process A + e → A ~ 7 is determined to be the rate control step of the bischondronate reduction reaction. The standard rate constant of solute exchange reaction, logk_s ~ (sol), was 7.04, and it was confirmed that the disproportionation mechanism was the main one in the homogeneous catalysis.