乙醇酸与乙醛酸的萃取分离

SEPARATION OF GLYCOLIC ACID AND GLYOXYLIC ACID BY EXTRACTION

以乙醇酸和乙醛酸的稀溶液为分离对象 ,采用三烷基氧磷 (TRPO)为萃取剂、甲基异丁基酮 (MiBK)为稀释剂 ,研究了单、双溶质有机酸的萃取分离特性 ,测定了TRPO、有机酸的浓度等因素对单、双溶质有机酸萃取平衡的影响 ,在适当假定的基础上 ,建立了描述TRPO萃取乙醇酸、乙醛酸单、双溶质特性的数学模型 .结果表明 ,随TRPO浓度的增大 ,分离系数 β(glycolic /glyoxylic) 由小于 1逐渐增大至大于 1,乙醇酸与TRPO的萃合物有 1∶1和 1∶2两种形式 ,采用单溶质萃取反应平衡常数预测双溶质萃取的结果 ,预测值与实验值相当接近 .同时 ,还对三烷基胺、磷酸三丁酯等萃取剂分离乙醇酸和乙醛酸的特性进行了讨论 .

The extraction behavior of single acid of glycolic acid and glyoxylic acid, and their mixture were investigated with TRPO as extractant and MiBK as diluent, and the effect of the concentration of TRPO and solute on the distribution coefficients were measured. The mathematical models describing the extraction equilibrium were proposed based on some assumptions. The experimental results showed that the complexes of glycolic acid with TRPO were in the forms of 1:1 and 1:2. The separation factor of glycolic acid to glyoxylic acid increased with TRPO concentration from less than 1 to larger than 1. The models parameters K11 and K12 in the single acid system can be used to predict extraction equilibrium behavior in the mixture acid systems. Finally, the separation conditions using other compounds, Alamine 336 and TBP, as extractant were also discussed.