固定床电解槽变电流电解乙二醛合成乙醛酸

研究了支持电解质、阳极类型和变电流电解方式等因素对电解乙二醛合成乙醛酸过程的电流效率和乙醛酸选择性的影响。在选用的支持电解质中盐酸是最合适的支持电解质 ;固定床阳极电解效果优于平板型阳极电解效果 ;变电流电解效果好于恒电流电解效果。当阳极电解液初始组成为w(乙二醛 ) =7.0 %、w(盐酸 ) =8.0 % ,阴极电解液组成为w(硫酸 ) =2 0 %的水溶液 ,变电流电解的平均电流密度为 15 35A/m2 时 ,电流效率为 85 .0 %、乙醛酸选择性为 94.3% ,阳极初产品中m(乙醛酸 )∶m(乙二醛 )≥ 40∶3。

Varying Current Electro-synthesis of Glyoxalic Acid from Glyoxal in the Fixed-bed Electrolytic Cell

The effects of inorganic supporting electrolytes,anode structure and varying current electrolysis on the current efficiency and selectivity for glyoxalic acid in the process of electro synthesis of glyoxalic acid from glyoxal were investigated.It was found that hydrochloric acid was the best among the employed inorganic supporting electrolytes,the electrolytic result of fixed bed anode was better than that of flat plate anode,and the electrolytic result of varying current electrolysis was better than that of constant current electrolysis.The average current density of varying current electro synthesis of glyoxalic acid from glyoxal was 1535 A/m 2,the current efficiency was 85 0% and the selectivity for glyoxalic acid was 94 3%.The optimal composition of anodic electrolyte was 7 0% glyoxal and 8 0% hydrochloric acid(W/W).The mass ratio of glyoxalic acid to glyoxal in primary anodic product was over 40∶3.