Progresses in polysaccharide and lignin-based ionic liquids: Catalytic applications and environmental remediation

Abstract

Today, the use of heterogeneous catalysts for various chemical and environmental transformations is of great interest. For this aim, researchers have applied different natural or synthetic supports for the heterogeneity of catalysts. The most widely used catalyst supports are perlite, bentonite, diatomite, and synthetic and natural polymers. Natural polymers (biopolymers) are one of the most promising compounds, which are widely applied as efficient and green supports. Among biopolymers, polysaccharides are highly regarded as catalyst supports by researchers. Many studies have been performed on improvements in the synthesis, characterization, and applications of biopolymers such as alginate, cellulose, lignin, chitin/chitosan and starch based catalysts. These polymers have some advantages such as biodegradability, biocompatibility, non-toxicity, and unique structures. This review paper describes the applications of alginate, cellulose, chitosan, starch and lignin supported ionic liquids (ILs) as catalysts for many catalytic and environmental applications. These catalysts are applied in reactions such as acetalization, hydrogenation, condensation, reduction, oxidation, epoxidation, and synthesis of 1,2,3-triazoles, dichlorophenylphosphine, diaryl ether, etc. As green resources, polysaccharides and lignin-based catalysts have many merits such as low cost, availability, good stability, recyclability, etc.