间接电氧化媒质Ce^(4+)/Ce^(3+)的循环与再利用

Recycle and reuse of Ce^(4+)/Ce^(3+) medium used in indirect electro-oxidation synthesis

设计了一种适用于间接电氧化合成反应,中试规模的填充式隔膜电解槽。该电解槽以铜板为阴极,PbO2/Ti石墨颗粒填充电极为阳极,电解液[0.16mol/L Ce2(SO4)3,1.5 mol/L H2SO4]采用外循环的方式控制其温度为30~50℃,在50A/m2的电流密度下电解,获得大于80%的电流效率。讨论了电极材料、电流密度、电解液温度、Ce3+浓度和循环次数等对电流效率的影响。其中Ce3+浓度是限制电流密度和影响电流效率的主要因素;电解液在间接电氧化对甲氧基甲苯反应中连续循环使用20次,仍然保持高于85%的电流效率;PbO2/Ti石墨颗粒填充电极使用寿命超过6个月。

A novel filling dectrolytic cell for scale-up indirect electro-oxidation synthesis is designed, in which copper is used as a cathode and PbO2/Ti filled with graphite particles as an anode. The electrolyte solution consisting of 0.16 mol/L of Ce2（SO4）3 and 1.5 mol/L of H2SO4 is cycled outside and controlled at 30 - 50℃. At the current density of 50A/cm^2, the current efficiency obtained is higher than 80%. Also, the effects of factors such as electrode materials, current density and electrolyte solution temperature, the concentration of Ce^3＋ and cycle numbers on the current efficiency are discussed. It is found that the concentration of Ce^3＋ is the main factor which limits current density and affects the current efficiency. After 20 cycles in the indirect electro-oxidation of anode p-methoxy toluene,the current efficiency still retains above 85%. The life-time of PbO2/Ti with filled graphite particles anode is over than six months.