利用醋酸稀溶液生产绿色化学品——醋酸钙镁盐的研究

结合醋酸稀溶液的合理回收和利用 ,以生产绿色化学品———醋酸钙镁盐 (CMA)为目的 ,采用化学萃取将醋酸富集于萃取剂相 ,再用钙镁氧化物为反萃剂 ,反萃生成CMA为工艺路线 ,系统地进行了负载醋酸有机相反萃性能的研究。考察了以三烷基胺 (Alamine 3 3 6) 正辛醇 煤油为萃取剂 ,CaO、MgO及其混合物为反萃剂时 ,反萃剂浓度、负载醋酸初始浓度、相比以及反萃液中醋酸盐初始浓度对反萃率的影响 ,并对反萃过程的机理及CMA中钙镁比例的影响因素进行了讨论。实验结果表明 ,钙镁氧化物可有效地反萃溶剂中的醋酸溶质 ,以生产绿色化学品———醋酸钙镁盐 ;当反萃液pH值大于 6.5时 ,萃取分配常数为 5 ,可有效地预测不同实验条件下的反萃率 ,误差小于± 15 % ;反萃液中Ca∶Mg的值与多种因素有关 ,生产中应注意调节起始的Ca∶Mg比例 ,以保持反萃液中合适的钙镁比例。

Study on Producing the Green Chemicals--Calcium Magnesium Acetate by Utilizing Dilute Solution of Acetic Acid

Producing green chemicals, calcium magnesium acetate (CMA), was investigated from acetic acid dilute solution by concentrating acetic acid in organic phase with chemical extraction first, then back-extraction to form CMA with CaO/MgO for making good use, and recovery dilute solution of acetic acid. The second, back-extraction step was studied systematically. The effect of content of chemical association agent, the concentration of CaO/MgO,volume ratio, initial concentration of acetic acid in organic phase and in stripping phase on the recovery yield were measured by using Alamine 336 (in n-octanol-kerosene) as extractant. The back-extraction mechanism and concentration ratio of calcium to magnesium in stripping solution was discussed. The result showed that CaO/MgO back-extracted acetic acid more efficient. This technology is feasible. Extraction distribution constant of 5 could be used to predict the recovery yield under different operation conditions for pH>6.5 with calculating deviation ±15%. The concentration ratio of calcium to magnesium in striping solution depended on stoichiometric ratio of CaO/MgO to acetic acid, the larger the stoichiometric ratio,the less the concentration of magnesium in striping solution.