Antonilli Marco, Bottari Emilio, Festa Maria Rosa
Dipartimento di Chimica, Università La Sapienza P.le A. Moro 5, 00185 Roma.
Ann Chim. 2007 Jan-Feb;97(1-2):39-48. doi: 10.1002/adic.200690084.
Taurocholate (TC) and taurodeoxycholate (TDC) in aqueous solutions, in the presence of sodium and hydrogen ions can give micellar products, even differently protonated. This phenomenon is investigated in this paper to explain whether the assumption of hydrogen ions is to attribute to the micellar aggregates, or to the protonation of taurocholate and taurodeoxycholate, respectively. In the course of this research, often the formation of gel occurred immediately after the mixture of the reagents (sodium, hydrogen ions and anions of bile acids) or after some time, depending on the concentrations of the reagents. No author mentions this evidence, but experiments carried out in the presence of gel are not reproducible because the investigated solutions cannot be considered in real equilibrium. The protonation study was performed by means of electromotive force measurements of a galvanic cell involving a glass electrode, at 25 degrees C and 1.00 mol dm(-3) NaCl, as ionic medium. The obtained protonation constants had the following values: log k1 = 0.07+/- 0.02 for TC and log k'1 = 1.60 +/- 0.03 for TDC.
在水溶液中，在钠离子和氢离子存在的情况下，牛磺胆酸盐（TC）和牛磺脱氧胆酸盐（TDC）能够形成胶束产物，甚至是不同程度质子化的胶束产物。本文对这一现象进行了研究，以解释氢离子的假设是归因于胶束聚集体，还是分别归因于牛磺胆酸盐和牛磺脱氧胆酸盐的质子化。在这项研究过程中，根据试剂的浓度，通常在试剂（钠、氢离子和胆汁酸阴离子）混合后立即或一段时间后会形成凝胶。没有作者提及这一现象，但在有凝胶存在的情况下进行的实验无法重复，因为所研究的溶液不能被认为处于真正的平衡状态。质子化研究是在25℃和1.00 mol dm⁻³ NaCl作为离子介质的条件下，通过涉及玻璃电极的原电池的电动势测量来进行的。得到的质子化常数具有以下值：TC的log k1 = 0.07 ± 0.02，TDC的log k'1 = 1.60 ± 0.03。
