Oil palm empty fruit bunch (OPEFB) (Elaeis guineensis Jacq.) cellulose conversion into levulinic acid using hierarchical Mn/ZSM-5 heterogeneous catalyst

Abstract

Oil palm empty fruit bunch (OPEFB) is one of the potential biomasses containing cellulose that can be used as a source for renewable energy. However, the cellulose is tightly connected with lignin in lignocellulose system, which needs to be separated, so called delignification, before being used. To investigate the effect of delignification on conversion reaction, the pretreated cellulose was treated with different delignification processes, i.e. alkali delignification using 10 % NaOH (w/v) and oxidative delignification using 2 % NaOCl (v/v). Furthermore, cellulose conversion from OPEFB into levulinic acid was performed using hierarchical Mn/ZSM-5 (Mn/Hi-ZSM-5) heterogeneous catalyst with various reaction times and concentration of H3PO4. The cellulose conversion into levulinic acid in the absence of catalyst was also conducted to study the effect of catalyst. High Performance Liquid Chromatography (HPLC) analysis showed the highest cellulose conversion into levulinic acid was achieved using cellulose from alkali delignification (28.08 % yield) in optimum reaction condition of 40 % H3PO4 (v/v), 30 % H2O2 (v/v), and 0.1 g of Mn/Hi-ZSM-5 at 100 °C for 10 h. Mn/Hi-ZSM-5 revealed good selectivity for levulinic acid with the absence of 5-HMF as an intermediate compound in conversion reaction.