Solvent-free synthesis of polysaccharide derivatives via heterogeneous Schiff base chemistry†
A series of modified polysaccharide polymers were prepared via a solvent-free synthesis involving heterogeneous Schiff base reaction of carboxymethyl chitosan (CMCS) with diverse aldehydes: hexanal, citral, benzaldehyde, 4-methoxybenzaldehyde, 4-chlorobenzaldehyde, and trans-cinnamaldehyde. The prepared CMCS derivatives were extensively studied in terms of their physicochemical, mechanical and morphologic properties. The presented solvent-free method allows multicycle preparation of the desired products. The properties of products prepared by the new method and traditional solvent-based synthesis were compared. The new process meets the essential requirements of green chemistry by diminishing waste products and eliminating organic solvents, while maximizing the use of the involved reagents. Being easily adjusted to suit various substituents, this method offers a potential platform for a formation of new materials and promotes environmentally friendly industrial practices.