Controlling cellulose feedstock size allows for modification of cellulose-based carbon-based solid acid size

Abstract

Carbon-based solid acids (CSA) have grown in popularity in recent years owing to their strong catalytic activity, thermal stability, and reusability. The size effect has a significant influence on the catalytic activity of carbon-based solid acids in heterogeneous catalysts. The impacts of raw material size on the shape, sulfonation degree, and catalytic activity of produced carbon-based solid acids were examined in this article. Various sizes of microcrystalline cellulose (MCC), cellulose nanocrystals (CNCs), and cotton fiber pulp (CP) were used as carbon sources in a simple carbon-sulphonation method to synthesize carbon-based solid acids. The produced CSA has a high concentration of sulphonic acid groups, as well as hydroxyl and carboxyl groups, and exhibits remarkable catalytic activity for the conversion of xylan to xylose. The solid acids generated from MCC have the most homogeneous shape, the greatest degree of sulphonation, and the highest catalytic activity. The conversion rate of xylan hydrolysis to xylose was up to 58.8% under ideal reaction conditions (150 °C, 4 h), and the catalyst retained almost its initial level of activity after five cycles with no appreciable deactivation.Graphical abstract