Reduced isotropic Raman spectra of dilute sodium glycolate in aqueous solutions of NaOH (molalities ranging from 0.03 to 5.65 mol·kg⁻¹ in OH⁻) have been obtained at temperatures 5, 25, and 45 °C. The Raman spectra yielded evidence of the formation of a doubly-deprotonated glycolate dianion, ⁻O–CH₂–COO⁻ (Gly²⁻) from the decrease in the intensity of the hydroxyl O–H bending mode at 1365 cm⁻¹ with increasing basicity, and the 7 cm⁻¹ shift in the alcohol C–OH stretching mode (from 1079 to 1086 cm⁻¹ at 5 °C). Equilibrium quotients for the second ionization constant of glycolic acid, Q_2a,OH, which corresponds to the deprotonation of the glycolate hydroxyl group, were calculated from the peak area of the O–H bending mode as it decreased with higher NaOH molalities. Values for the equilibrium constant and the standard molar enthalpy of reaction at 25 °C: log K_2a,OH,298 = − 1.143 ± 0.059, and Δ_ionH°_2a,OH,298 = − 12.5 ± 1.6 kJ·mol⁻¹, were determined by regressing the experimental equilibrium quotients to a simple extended Debye–Hückel activity coefficient model. This is the first reported spectroscopic characterization of Gly²⁻and the first reported values for log K_2a,OH,298 and Δ_ionH°_2a,OH,298.

在 5、25 和 45 °C 的温度下，已获得稀乙醇酸钠在 NaOH 水溶液中的各向同性还原拉曼光谱（质量摩尔浓度范围为 0.03 至 5.65 mol·kg ^-1的OH ^{- ）。}拉曼光谱证明了双去质子化乙醇酸二价阴离子⁻ O–CH ₂ –COO ⁻ (Gly ²⁻ ) 的形成是由于羟基 O–H 弯曲模式在 1365 cm ⁻¹处的强度随着增加而降低碱度，以及酒精 C-OH 拉伸模式中的7 cm ^{-1位移（在 5 °C 时从 1079 到 1086 cm -1}）。乙醇酸第二电离常数Q的平衡商_2a,OH对应于乙醇酸羟基的去质子化，是根据 O-H 弯曲模式的峰面积计算的，因为它随着 NaOH 摩尔浓度的增加而降低。25 °C 时的平衡常数和标准摩尔反应焓值：log K _2a,OH,298 = − 1.143 ± 0.059, 和 Δ _ion H ° _2a,OH,298 = − 12.5 ± 1.6 kJ·mol ⁻¹ , 是通过将实验平衡商回归到一个简单的扩展 Debye-Hückel 活动系数模型来确定的。^{这是 Gly 2−}首次报道的光谱表征，也是 log K _{2a、OH、298}和 Δ_离子H的首次报道值° _2a,OH,298。