When processing lignocellulosic biomass materials to obtain platform molecules such as levulinic acid (LA), alkyl levulinates or γ-valerolactone (GVL), the choice of solvent is of prime importance for kinetics. The knowledge of relationships between reaction kinetics and solvent serves as a decision tool for process design. To determine such relationships, esterification reactions was chosen because such reaction steps are present in several biomass conversion processes. In this work, kinetic models of LA esterification by ethanol over sulfuric acid in polar aprotic solvent (GVL) and polar protic solvents (water or ethanol) were developed and evaluated by Bayesian statistics. The apparent dissociation constants in solvents were estimated by ePC-SAFT approach to distinguish the proton concentration from the rate constants. The developed models can fit the experimental concentrations of ethyl levulinate and predict the proton concentration. Using the Kalmet-Abboud-Taft equation, linear relationships between estimated rate constants and solvent properties were established at different temperatures. We observed that solvents with low polarizability and high bond acceptor capacity should be favored for this reaction. Hence, the reaction of esterification is faster in ethanol solvent than in GVL solvent than in water solvent.

在处理木质纤维素生物质材料以获得平台分子，例如乙酰丙酸 (LA)、乙酰丙酸烷基酯或 γ-戊内酯 (GVL) 时，溶剂的选择对于动力学至关重要。反应动力学和溶剂之间关系的知识可作为工艺设计的决策工具。为了确定这种关系，选择了酯化反应，因为这种反应步骤存在于几种生物质转化过程中。在这项工作中，通过贝叶斯统计开发和评估了在极性非质子溶剂 (GVL) 和极质子溶剂（水或乙醇）中乙醇与硫酸对 LA 酯化的动力学模型。通过 ePC-SAFT 方法估计溶剂中的表观解离常数，以区分质子浓度和速率常数。所开发的模型可以拟合乙酰丙酸乙酯的实验浓度并预测质子浓度。使用 Kalmet-Abboud-Taft 方程，在不同温度下建立了估计的速率常数和溶剂性质之间的线性关系。我们观察到具有低极化率和高键受体容量的溶剂应该有利于该反应。因此，酯化反应在乙醇溶剂中比在 GVL 溶剂中比在水溶剂中快。我们观察到具有低极化率和高键受体容量的溶剂应该有利于该反应。因此，酯化反应在乙醇溶剂中比在 GVL 溶剂中比在水溶剂中快。我们观察到具有低极化率和高键受体容量的溶剂应该有利于该反应。因此，酯化反应在乙醇溶剂中比在 GVL 溶剂中比在水溶剂中快。