Anionic micro-cellulose (AMC): preparation, characterization, and application as a novel heterogeneous base catalyst

This work describes simple preparation of different types of micro-fibrillated (AMCa, AMCb) and micro-crystalline alkaline celluloses (AMCc) by variation in treatment conditions of wax-, hemicellulose-, and lignin-free cellulose. The AMCs were characterized by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, and thermo-gravimetric analysis. The morphology and base-capacity of AMCs were deeply influenced by treatment temperature, stirring speed, and chemical reagents applied. The base capacities of micro-fibrils of AMCa/AMCc and micro-crystals of AMCb were 5.2, 5.6, and 6.9 mmol OH-/g, respectively, while all AMCs represented a higher thermal stability compared to cellulose. Among the fibrillated and crystalline AMCs, the white solid powder of AMCb demonstrated a superior catalytic performance in base-catalyzed selective hydration of nicotinonitrile to nicotinamide, while the catalyst was reusable for at least four subsequent reaction runs.