ScienceDirect
Microwave technology offers rapid, selective, and efficient heating, making it a valuable tool for process intensification. In this context, this study employed microwave energy for rapid reaction optimization and reliable kinetic analysis for the catalytic conversion of glucose. Dehydration (DeH) and retro-aldol condensation (RAC) are two main routes for the catalytic conversion of glucose into valuable platform chemicals such as levulinic acid, methyl lactate, and other byproducts. Both DeH and RAC reactions were analyzed together in this study, taking into account their competitive nature. The experimental investigation focused on examining the effects of solvent composition (0–100 % H2O with methanol as cosolvent), reaction temperature (140–180 °C), and catalyst-to-feed molar ratios (0.05–0.21) on the parallel Deh (HMF, levulinic acid, and methyl levulinate) and RAC (lactic acid and methyl lactate) reactions with the modern automated Chemspeed Swing synthesis apparatus equipped with a Biotage microwave reactor. The homogeneous Lewis acid (SnCl4·5H2O) was selected as a catalyst through our initial screening due to its activity for both DeH and RAC reactions. The experiments, conducted for 15 min under microwave irradiation, revealed that the highest yield of levulinic acid (50.5 mol %) was achieved in pure water at 180 °C, while the highest yield of methyl lactate (75.9 mol%) was obtained in a solvent mixture comprising 7.5 % water and 92.5 % methanol at 180 °C. Subsequently, rate models based on the power law kinetics were proposed, and the numerical values of the model parameters were determined from the screening experimental data using non-linear regression analysis with Aspen Plus software. These model parameters were further fine-tuned with additional time-resolved experiments performed under the optimal conditions identified for levulinic acid and methyl lactate. The model responses were in very good agreement with the experimental results. The rate equations with the kinetic parameters can be used for the reactor modeling, simulation, and optimization.
For details:
Experimental and kinetic study of the microwave-assisted catalytic conversion of glucose
Syed Ejaz Haider a, Joseph Install b, Miia Kokkonen b, Timo Repo b, Ville Alopaeus a
a) Department of Chemical and Metallurgical Engineering, School of Chemical Engineering, Aalto University, P.O. Box 11000, FI-00076 Aalto, Finland
b) Department of Chemistry, University of Helsinki, A. I. Virtasen aukio 1, P.O. Box 55, 00014 Finland
ScienceDirect
https://www.sciencedirect.com/science/article/pii/S0255270125005136
