三辛基甲基氯化铵萃取色氨酸的影响因素

研究了水相离子强度、无机盐类型、萃取剂浓度、水相初始 pH0 值对色氨酸在三辛基甲基氯化铵(TOMAC) /正辛烷体系中分配行为的影响。实验结果表明 ,色氨酸的分配系数随着离子强度的增加而降低 ,但是当离子强度增大到一定程度时变化趋于平缓 ;分析了由于离子强度的影响而使实际过程的分配系数与理想过程分配系数不同的原因 ,得出了离子强度与活度系数的关系式 ;在萃取过程中增加有机相萃取剂浓度可提高两相间的分配系数DA;提高水相 pH0 值能提高色氨酸在两相间的分配系数DA,但当 pH0 >11时 ,对分配系数的影响很小 ;阳离子均为Na+ 情况下 ,DCl- >DBr- ;阴离子均为Cl-时 ,DNa+ >DK+ 。

Factors Influencing the Extraction of Tryptophane by Tri-n-octylmethylammonium Chloride

The influence of ionic strength, kind of salt, concentration of extractant and initial pH value of water phase on the distribution coefficient of tryptophane(Trp) in the extraction process carried out in tri-n- octylmethylammonium chloride(TOMAC) system have been investigated. The results indicate that the distribution coefficient changes little with the increase of the ionic strength, when the latter is large enough. The difference in distribution coefficient obtained from experiments and theretical calculation has been analyzed, and an equation describing the relation between ionic strength and activity coefficient is obtained. The distribution coefficient of the Trp increases with increase of TOMAC concentration and initial pH value of water phase, but it is less affected when pH 0 is >11. For salts of the same cation Na +, D Cl->D Br-, and for salts of the same anion Cl -, D Na+>D K+.