摘要
以二(2-乙基己基)磷酸(D2EHPA)-正辛烷及D2EHPA-正辛醇萃取L-异亮氨酸为对象，研究了D2EHPA浓度、L-异亮氨酸初始浓度以及pH值对萃取平衡分配系数的影响。结果表明，在实验研究涉及的pH值范围内，分配系数先随pH的增加而增大，在3.5<pH<5区域，pH值对分配系数的影响较小。分配系数还随D2EHPA浓度的增加而增大。正辛醇加入有机相，萃取分配系数增大。D2EHPA与L-异亮氨酸生成萃合比为1∶1或2∶1的萃合物。证实了在D2EHPA萃取L-异亮氨酸的过程中存在着质子转移反应。建立的萃取平衡分配系数关联式的拟合精度是令人满意的。
The separation technique of extraction based on reversible chemical complexation can be high capacity and high selectivity for separating polar organic solutes from dilute solution. The downstream processing technology for the extraction and recovery of amino acid presents a challenging separation problem. A series of extraction equilibrium experiment for L-isoleucine with di (2-ethylhexyl)phosphoric acid (D2EHPA) dissolved in n-octane and 1-octanol were carried out in this paper. The effects of L-isoleucine concentration, D2EHPA concentration and pH on extraction distribution ratio were discussed in detail. In the 1.0<pH<3.5 range, distribution ratio D increases with the increase of pH, but changes slightly in the 3.5<pH<5.0 range. The extraction distribution ratio increases when the diluent is changed from n-octane into 1-octanol. The data indicate that during extraction the L-isoleucine in D2EHPA system will form both (1∶1) and (2∶1) D2EHPA-L-isoleucine complexes. The infrared spectrogram of organic phase loaded solute illustrates that pH condition had little effect on the structure of complex. The proton-transfer reaction is again demonstrated in the extraction of (-amino acid with D2EHPA. An expression of the equilibrium distribution ratio was proposed.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2000年第5期415-419,共5页
Journal of Chemical Engineering of Chinese Universities
基金
国家自然科学基金资助项目(29836130)。
