Activity-Based Models to Predict Kinetics of Levulinic Acid Esterification.

Area of Science:

• Chemical Engineering
• Thermodynamics
• Reaction Kinetics

Background:

• Solvents critically influence biomass conversion processes, affecting dissolution, reaction kinetics, and catalyst performance.
• Existing activity-based models predict kinetics and equilibria but struggle to incorporate catalyst effects on kinetics.
• Thermodynamic models have not yet successfully predicted catalyst influence on reaction kinetics.

Purpose of the Study:

• To utilize the advanced ePC-SAFT thermodynamic model to predict reactant and catalyst activities.
• To investigate the homogeneous acid-catalyzed esterification of levulinic acid (LA) with ethanol.
• To develop a method for predicting catalyst influence on reaction kinetics using thermodynamic modeling.

Main Methods:

• Applied the advanced ePC-SAFT model to predict activities under varying conditions (temperature, concentrations, GVL cosolvent).
• Simultaneously solved the dissociation equilibrium of the sulfuric acid (H2SO4) catalyst.
• Related reaction kinetics to proton activity and applied kinetic models.

Main Results:

• Successfully predicted the influence of the catalyst on reaction kinetics.
• ePC-SAFT model parameters were fitted using reaction-independent phase equilibrium data.
• Determined key reaction properties including reaction enthalpy, activation energy, and intrinsic reaction rate constant (k=0.011 s⁻¹ at 323 K).

Conclusions:

• The developed procedure enables a priori prediction of catalyst, solvent, and reactant concentration effects on LA esterification.
• Accurate prediction of kinetics was achieved by integrating catalyst dissociation equilibrium with proton activity.
• This thermodynamic approach advances the understanding and prediction of catalytic processes in biomass conversion.