【摘要】 本文用不同pH的柠檬酸缓冲液,加入或不加高氯酸钠等无机盐,浸泡滤纸后层析奎尼丁和辛可宁。证明在pH6以下基本上是一价离子对萃取机理。 为研究机理引入了层析常数R_d,它与热办学常数成正比并有加和性。 本文提出了一种用纸上层析法测定解离常数的方法。用此法测得奎尼丁与辛可宁二价正离子的pK_a1分别为4.82与4.77。更多还原

【Abstract】 Cinchonine and quinidine are developed on papers impregnated with citric buffer of various pH, with or without additional salts. The data obtained are dealt with in terms of a new parameter R_d. R_d is defined as R_f/（1-R_f）. It has the advantage of being additive with respect to individual species and proportional to the partition coefficient.The R_d^o, which are values in the absence of additional salt, increase with increasing pH, and are consistent with the combination of free base and monovalent ion pair extraction mechanisms. The former predominates at pH6, but the latter becomes predominant as the pH decreases.when the papers are impregnated with buffer of various pH and being 0.1M to NaClO₄, the R_d agrees well with the monovalent ion pair mechanism by plotting lg（R_d-R_d^o） against pH. From the curves the pK_a2 of quinidine and cinchonine are determined to be 4.82 and 4.77 respectively, thus providing a new approach for determination of ionization constants.In the presence of various kinds of salts, all in 0.1M concentration, the R_d values are at least ten times larger thau R_d^o. The orders are all NaBr>NaCl>NaClO₄, These are all in agreement with ion pair mechanism,更多还原