Continuous Conversion of Glucose into Methyl Lactate over the Sn-Beta Zeolite: Catalytic Performance and Activity Insight

In this study, we developed an efficient technology for the continuous conversion of glucose into methyl lactate over the Sn-Beta zeolite with a trickle bed reactor. The catalyst exhibited a high yield of 59.7% for lactic acid in water, and the total yield of methyl lactate and xylitol reached 59.8% (37.3% for methyl lactate) in methanol. The continuous evaluation of Sn-Beta demonstrated a maximum yield of 45.0% for methyl lactate along with 99% conversion of glucose in methanol, and the catalyst was continuously operated for over 434 h at 165 °C. The changes in Sn coordination and fouling stand as the dominant reason for the activity loss of Sn-Beta. Compared with the rapid decline of activity in water, reaction in methanol exhibited much less carbon deposition, structural changes, and Sn leaching after a long-term operation. The promising result indicated the potential application of Sn-Beta as an industrial catalyst for biomass utilization.