Catalytic hydrolysis of cellulose and oil palm biomass in ionic liquid to reducing sugar for levulinic acid production

Biomass is now regarded as a potential feedstock to produce renewable valuable chemicals that can be derived from sugar. In this study, it was demonstrated that Fe/HY catalyst was able to promote the hydrolysis in ionic liquid of oil palm biomass to reducing sugar without a prior pretreatment step. Initially, cellulose was utilized as a model compound and the effects of several variables including temperature, time, catalyst loading, cellulose loading, and 1-butyl-3-methylimidazolium bromide (BMIMBr) purity on the hydrolysis process were evaluated. A total reducing sugar (TRS) yield of 60.8% was obtained using Fe/HY catalyst in BMIMBr at 120 °C within 3 h. Next, the same catalyst was applied for direct hydrolysis of oil palm frond (OPF) and empty fruit bunch (EFB). The TRS yields obtained were 27.4% and 24.8%, respectively, while the efficiencies were 54.6% and 58.5% for OPF and EFB, respectively. The catalyst, tested for five runs, exhibited a minimal loss in the catalytic activity signifying its potential recyclability ability. Further conversion of the cellulosic hydrolysate led to promising levulinic acid yield and process efficiency. The experimental results confirmed that Fe/HY catalyst and BMIMBr have the potential to be used in a lignocellulosic biorefinery at mild process conditions for processing renewable feedstocks.