Research on the transformation of Oil Palm Empty Fruit Bunches (OPEFB) through pretreatment process using ionic liquid triethylammonium hydrogen sulphate (IL [TEA][HSO4]) was completed. The stages of the transformation process carried out were the synthesis of IL with the one-spot method, optimization of IL composition and pretreatment temperature, and IL recovery. The success of the IL synthesis stage was analyzed by FTIR, H-NMR and TGA. Based on the results obtained, it showed that IL [TEA][HSO4] was successfully synthesized. This was indicated by the presence of IR absorption at 1/λ = 2814.97 cm−1, 1401.07 cm−1, 1233.30 cm−1 and 847.92 cm−1 which were functional groups for NH, CH3, CN and SO2, respectively. These results were supported by H-NMR data at δ (ppm) = 1.217–1.236 (N–CH2–CH3), 3.005–3.023 (–H), 3.427–3.445 (N–H+) and 3.867 (N+H3). The TGA results showed that the melting point and decomposition temperature of the IL were 49 °C and 274.3 °C, respectively. Based on pretreatment optimization, it showed that the best IL composition for cellulose production was 85 wt%. Meanwhile, temperature optimization showed that the best temperature was 120 °C. In these two optimum conditions, the cellulose content was obtained at 45.84 wt%. Testing of IL [TEA][HSO4] recovery performance for reuse has shown promising results. During the pretreatment process, IL [TEA][HSO4] recovery effectively increased the cellulose content of OPEFB to 29.13 wt% and decreased the lignin content to 32.57%. The success of the recovery process is indicated by the increasing density properties of IL [TEA][HSO4]. This increase occurs when using a temperature of 80–100 °C. The overall conditions obtained from this work suggest that IL [TEA][HSO4] was effective during the transformation process of OPEFB into cellulose. This shows the potential of IL [TEA][HSO4] in the future in the renewable energy sector.

In recent years, various studies have been utilized lignocellulosic biomass from oil palm empty fruit bunches (OPEFB) to be converted into bioethanol fuels. In this study, we present the techno-economical preparation for biomass pretreatment based on triethylamine hydrogen sulfate ([TEA][HSO4]) ionic liquid. Synthesis, pretreatment, and recovery of [TEA][HSO4] ionic liquid have been carried out via the one-pot method. Based on these results, the synthesized [TEA][HSO4] has been characterized using IR spectroscopy showing the appearance chemical groups such as H, CH3, CN, and SO2. In addition, H-NMR spectroscopy was presenced the CH3CH2- structure towards low ppm. Thermal stability has also demonstrated unique physical properties of ionic liquid (IL) with a melting point of 49°C and a decomposition temperature of 274.3°C. The effectiveness to produce the chemical components shows that the useful use of [TEA][HSO4] was successfully synthesized with an optimum composition of 83% resulting in chemical levels of 45.84% (cellulose), 5.00% (hemicellulose), and 34.40% (lignin). The recovered [TEA][HSO4] with a composition of 90.90% was effective in reducing the lignin content about 80%. These results also depend heavily on the temperature and separation techniques applied during the pretreatment process.