【摘要】 香草酸和对羟基苯甲酸都是存在于自然界中的天然抗氧化剂，具有抗菌、消炎和抗癌等生物活性。在25.0℃和1.0 mol/L离子强度下我们研究了它们在各种不同缓冲溶液中的电子光谱，并通过光度滴定的方法计算得到了二者在水溶液中的解离平衡常数pK_a1值和pK_a2值。在获得这些数据后就可以较为方便地对香草酸和对羟基苯甲酸的不同质子化形态随pH值的分布情况进行分析，这将对研究它们的抗氧化反应机理提供有力的支撑。更多还原

【Abstract】 Vanillic acid（VA） and p-hydroxybenzoic acid（HBA） are both natural antioxidants found in nature, which have good antibacterial, anti-inflammatory and anticancer properties.We have studied their UV-Vis spectra as a function of pH at 25.0 ℃ and 1.0 mol/L ionic strength. Consequently, their acid dissociation constants pK_a1 and pK_a2 have been determined by a spectrophotometric titration method. With the acquired pK_a1 and pK_a2 values, the distributions of the protolytic species of VA and HBA with pH can be described explicitly, conferring a good foundation for studying their anti-oxidative mechanisms.更多还原