Protonation of nicotinic acid has been investigated by means of potentiometric titrations at different temperatures 283.15 ≤ T (K) ≤ 383.15 and ionic strengths of NaCl(aq), 0.12 ≤ I (mol·kg−1) ≤ 4.84 and mixed NaCl with MgCl2 or CaCl2. Stability constants of the CaL+ and MgL+ species were obtained by means of the ΔpK method. Different models (e.g. Debye–Hückel type equation, Specific Ion Interaction Theory, Pitzer and van’t Hoff) were applied to account for the ionic strength and temperature dependences, in order to obtain data in a standard state and parameters to calculate stability constants in any point of our experimental domain. Speciation studies were performed simulating the conditions of natural fluids. Literature data were investigated for comparison with the experimental results here obtained.

中文翻译：

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不同温度和离子强度下烟酸与H+、Na+、Ca2+和Mg2+相互作用的热力学研究

通过电位滴定法在不同温度 283.15 ≤ T (K) ≤ 383.15 和 NaCl(aq)、0.12 ≤ I (mol·kg−1) ≤ 4.84 和混合 NaCl 与 MgCl2 或氯化钙。CaL+ 和 MgL+ 物质的稳定性常数通过 ΔpK 方法获得。应用不同的模型（例如 Debye-Hückel 型方程、特定离子相互作用理论、Pitzer 和 van't Hoff）来解释离子强度和温度的依赖性，以获得标准状态下的数据和参数以计算稳定常数我们实验领域的任何一点。形态研究是通过模拟天然流体的条件进行的。研究文献数据以与此处获得的实验结果进行比较。