非均相电解氧化Mn(II)及间接电合成苯甲醛

Heterogeneous Phase Electrolytic Oxidation of Mn(II) and Indirect Electrolytic Synthesis of Benzaldehyde

以铅作电极, 对Mn(II)在酸性介质中于非隔膜电解池内进行非均相电解氧化。在阳、阴极的面积比为3∶1, 0(3mol·L-1 Mn(II) 、40%H2SO4 ，阳极电流密度为60mA·cm-2和室温的电解条件下，将Ｍn(II) 氧化为Ｍn(III)。在温度为60oC和0.3%相转移催化剂四丁基溴化铵存在下，用Mn(III)氧化甲苯合成苯甲醛。经甲苯萃取的水相母液可多次循环使用，电流效率大于60%，合成苯甲醛的产率接近60%，基本无副产物生成。

The heterogeneous electrolytic oxidation of Mn(II) to Mn(III) in acid media in an undiphragm cell, where lead sheets were used as the anode and cathode, was investigated. Tetrabutylammonium bromide was used as the phase transfer catalyst , the electrolyte of Mn(III) could react with toluene to synthesize benzaldehyde. The areas of anode and cathode were 15 and 5cm-2 respectively, the electroyte was made of 150mL 0.3mol·L-1Mn(II) and 40% H2SO4, the current density of anode was 60 mA·cm-2. The electrolytic oxidation of Mn(II) to Mn(III) was at room temperature for 90min, then 5mL toluene and 0.5g tetrabutylammonium bromide were added into the electrolyte, and the temperature was set at 60 oC. After reaction, the produced benzaldehyde was extracted from the electrolyte by toluene, and water phase could continue to be used in the cell. The results were that the current efficiency was still more than 60% after 6 cycle-use and the yield of benzaldehyde was 59.5%. No by-product was found in synthetic product.