Waste paper-derived magnetic carbon composite: A novel eco-friendly solid acid for the synthesis of n-butyl levulinate from furfuryl alcohol

Abstract

Waste paper, a promising renewable source of cellulose, was successfully prepared into a magnetic carbonaceous solid acid (SMWP) via a facile and integrated impregnation-pyrolysis–sulfonation process. The resultant catalyst was confirmed to possess a porous structure with a high surface area, various oxygen-containing functional groups and contain Fe3O4 components. The SMWP catalyst also exhibited a high catalytic activity in the alcoholysis of furfuryl alcohol with n-butanol, up to 90.6% yield of n-butyl levulinate and 100% conversion of furfuryl alcohol was achieved by optimizing the reaction conditions. In comparison with other solid acids such as HZSM-5 zeolite and Nafion-212 resin, the better performance of SMWP could be explained by its strong acidity and good affinity to furfuryl alcohol, which results from the synergistic effect of SO3H, COOH and phenolic OH groups on the carbon surface. Moreover, the catalyst could be easily recycled with an external magnet and reused 7 times without a distinct loss of activity. The findings in this work provided an environmentally friendly manner for waste paper utilization and fuel additive production.