Bates Roger G, Hetzer Hannah B
J Res Natl Bur Stand A Phys Chem. 1960 Sep-Oct;64A(5):427-432. doi: 10.6028/jres.064A.043. Epub 1960 Oct 1.
The dissociation constant of 4-aminopyridinium ion in water at 11 temperatures from 0° to 50° C has been determined from electromotive force measurements of 19 approximately equimolal aqueous buffer solutions of 4-aminopyridine and 4-aminopyridinium chloride. Cells without liquid junction were used; the cell is represented as follows: where is molality. Between 0° and 50° C, the dissociation constant ( ) is given as a function of temperature () in degrees Kelvin by The changes of Gibbs free energy (Δ°), of enthalpy (Δ°), of entropy (Δ°), and of heat capacity (Δ °) for the dissociation process in the standard state were calculated from the constants of this equation. At 25° C the following values were found: Thermodynamic constants for the basic dissociation of 4-aminopyridine at 25° C were also computed.
通过对19种近似等摩尔的4-氨基吡啶和4-氨基吡啶盐酸盐水溶液缓冲溶液进行电动势测量，测定了4-氨基吡啶离子在0℃至50℃的11个温度下在水中的解离常数。使用了无液接电池；该电池表示如下：其中 为质量摩尔浓度。在0℃至50℃之间，解离常数（ ）作为开尔文温度（）的函数表示为 。根据该方程的常数计算了标准状态下解离过程的吉布斯自由能（Δ°）、焓（Δ°）、熵（Δ°）和热容（Δ °）的变化。在25℃时得到以下值：还计算了25℃时4-氨基吡啶碱性解离的热力学常数。
