In this article, the study of molecular interactions in liquid systems containing industrially and biologically important solvents with minimal environmental damage has been done. Density ($\rho$) and refractive index ($n_D$) of binary systems comprising ethyl lactate (EL) + ethylene glycol (EG) and di-ethylene glycol (DEG) at various mole fractions and T = (298.15 to 313.15) K along with pure components have been measured. The observed parameters were further used for determination of excess molar volumes ($V_m^E$), partial molar volumes (${\overline{V}}_m$), excess partial molar volumes (${\overline{V}}_m^E$), deviations in refractive index (${\mathrm{\Delta }}_{\varphi }{n}_D$) and deviations in molar refraction (${\mathrm{\Delta }}_{\varphi }{R}_M$). Redlich-Kister coefficients along with standard deviations have been obtained by approximation of data to polynomial equation. The obtained $V_m^E$ results have been investigated theoretically by means of Prigogine-Flory-Patterson (PFP) and Graph theories to estimate type and nature of interactions among constituent molecules which can be used to explain the changes in physicochemical properties of the mixtures. By analysing experimental data in light of PFP Theory, Interactional and characteristic pressure contributions have been found negative values for both the binary systems whereas free volume contribution possess positive sign. The structural variation of the components in the mixtures due to change in molecular interactions has been discussed by Graph theory. Fourier Transform InfraRed (FT-IR) studies have also been performed for pure and equimolar mixtures to enlighten the experimental outcomes. It confirmed the rupture of pre-existing bonding in lactate and the formation of new hydrogen bonds with glycols.

在这篇文章中，研究了液体系统中的分子相互作用，该系统包含对环境破坏最小的工业和生物重要溶剂。密度 （$\rho$) 和折射率 ($n_D$) 的二元系统包括乳酸乙酯 (EL) + 乙二醇 (EG) 和二甘醇 (DEG)，在不同的摩尔分数和 T = (298.15 到 313.15) K 以及纯组分已被测量。观察到的参数进一步用于确定过量摩尔体积（${伏}_{米}^{乙}$), 偏摩尔体积 (${\overline{伏}}_{米}$), 多余的偏摩尔体积 (${\overline{伏}}_{米}^{乙}$), 折射率偏差 (${\mathrm{\Delta }}_{\phi }{n}_D$) 和摩尔折射偏差 (${\mathrm{\Delta }}_{\phi }{\mathrm{电阻}}_{米}$）。Redlich-Kister 系数以及标准偏差是通过将数据近似为多项式方程而获得的。获得的${伏}_{米}^{乙}$已经通过 Prigogine-Flory-Patterson (PFP​​) 和图理论对结果进行了理论研究，以估计组成分子之间相互作用的类型和性质，可用于解释混合物物理化学性质的变化。通过根据 PFP 理论分析实验数据，已经发现两个二元系统的相互作用和特征压力贡献为负值，而自由体积贡献具有正号。图论已经讨论了由于分子相互作用的变化而引起的混合物中组分的结构变化。还对纯和等摩尔混合物进行了傅里叶变换红外 (FT-IR) 研究，以启发实验结果。