Preparation of sulfonated carbonaceous solid acid catalysts by fuming sulfuric acid from different lignocellulosic sources and application for the conversion of Acacia mangium wood sawdust-derived glucose and fructose into levulinic acid

Four types of high-acidity carbon-based solid acid catalysts (CBSCs) were successfully synthesized from wood sawdust, sugarcane bagasse, coconut shell, and wood sawdust-derived lignin using fuming sulfuric acid (FSA) as the sulfonating agent. The synthesized CBSCs were successfully applied to the conversion of wood sawdust-derived glucose and fructose into levulinic acid. The findings show that FSA can provide the CBSCs with higher acidity (8.0–13.0 mmol/g) than conventional concentrated sulfuric acid. Under the suitable conditions established in this work, levulinic acid was formed with a yield of more than 50 wt% over glucose when using the synthesized CBSCs at a dosage of 30 wt% over the amount of sugar.