Solvent-free synthesis of a zirconium-carbon coordination catalyst for efficient aqueous-phase production of lactic acid from xylose.

It is highly desirable but of challenge to develop an efficient process for lactic acid (LaA) production from xylose performed in water. Herein, a novel catalyst prepared via a facile solvent-free coordination route is developed to efficiently produce LaA from xylose in water. The structural properties of the prepared catalyst and the reaction conditions are systematically investigated. The production rate of LaA at 190 °C in water is up to 1.8 h−1, outperforming the most recent reports (below 1.1 h−1). Detailed experimental and characteristic studies reveal that the presence of Lewis acidic sites and basic sites in the catalyst structure can not only lower the energy barrier of xylose conversion but also boost the efficient conversion of the active reaction intermediates into LaA. The findings of this work will provide a new approach for the efficient production of LaA from carbohydrates. [Display omitted] • Zirconium-carbon coordination catalysts are prepared via a solvent-free method. • Zr-BC shows excellent activity in the conversion of xylose to LaA. • Production of LaA proceeds over both Lewis acidic sites and base sites on Zr-BC. • The substrate for LaA production can be extended to other carbohydrates. [ABSTRACT FROM AUTHOR]