Natural lignocellulose welded Zr–Al bimetallic hybrids for the sustainable conversion of xylose to alkyl levulinate

Abstract

The processing of C6 sugars to alkyl levulinate (AL), a versatile biomass-derived building block, can be readily implemented via the straightforward acid-catalyzed reaction in alcohol medium while it remains a challenge to produce AL from C5 sugars in the one-pot procedure over a monolithic catalyst. In this contribution, a budget and multifunctional natural lignocellulose welded Zr–Al bimetallic hybrid (ZrAl@CS-MSA) has been successfully constructed with crude corn stalk as a sustainable support. The becoming Lewis and Brønsted acid sites of ZrAl@CS-MSA catalyst guarantee a high AL yield of 54.3% from xylose via a one-pot process in a renewable n-butanol medium. Experimental findings revealed that the sulfonic group of ZrAl@CS-MSA plays a significant role in the xylose dehydration, furfuryl alcohol etherification and alcoholysis reactions while Zr species is in charge of the transfer hydrogenation of furfural. The Al species enclosed in ZrAl@CS-MSA can regulate its Brønsted and Lewis acidity, accelerating the etherification and alcoholysis reactions as well as alleviating the over hydrogenation of AL. This work opens a green, sustainable and reliable avenue for producing C5 sugar-based AL using natural lignocellulose-related multifunctional catalysts.