Dissolution of Cellulose Biopolymer Using Alkoxy Linked Dicationic Ionic Liquids

Abstract

Cellulose is one of the widely available and abundant natural biopolymers alongside hemicellulose and lignin. Effective dissolution and separation process of cellulose are vital to diversify the applications of cellulose. This includes biofuel production, fermentation and fiber production. Although conventional solvents are widely used for cellulose dissolution, they still suffer from drawbacks such as high costs, poor thermal stability and high toxicity. Ionic liquids (ILs) had created an architectural platform in the area of cellulose dissolution with remarkable results. Even though ILs have been widely used for this application, the race to find the best ILs with optimum dissolution conditions remains a huge challenge. This chapter discusses the dissolution of cellulose using alkoxy linked imidazolium-based dicationic ILs coupled with chloride and acetate anions. More than 45% of dissolution of cellulose was achieved with acetate anion/DMSO mixture at room temperature. Characteristics XRD diffraction pattern was taken for cellulose before and after the dissolution with ILs. Crystallinity index (CI) and thermal stability of the regenerated cellulose were also reduced significantly, indicating effective penetration of ILs. This result can be further supported by the effect of anion as the H-bond acceptor and low viscosity in dicationic ILs/DMSO system, which increased the dissolution capacity of cellulose compared to monocationic ILs.