Effect of solvent pre-treatment on lignophenol production from oil palm empty fruit bunch fibres

Oil palm empty fruit bunches (EFB) are a by-product in the palm oil industry, and represent an abundant, inexpensive and renewable resource. EFB can be categorized as a lignocellulosic material due to its cellulose, hemicellulose and lignin contents. The purpose of this research was to investigate the effect of solvent pretreatment on lignophenol production from EFB. Two types of EFB were tested, i.e. treated ground EFB (LP1) and non-treated ground EFB (LP2). EFB has potential as a starting material for lignophenol production using a two-step process involving a phase separation system at room temperature (～28℃). This process utilizes the phenol derivative (p-cresol) and concentrated acid (72% sulphuric acid) whereby the lignin is dissolved in the organic phase and the carbohydrates are present in the aqueous phase after 1 hr of stirring. LP1 and LP2 were further analysed and characterized by Proton nuclear magnetic resonance (1H-NMR), Fourier transform infra-red spectroscopy (FTIR), gel permeation chromatography (GPC), ultraviolet spectroscopy (UV) and by thermomechanical analysis (TMA). The experiments gave sufficient information on the characteristics of the lignophenols from treated and untreated EFB. The lignophenols of LP1 and LP2 showed similar results in their characteristics while their molecular weights were 5759 and 5866, respectively. There was no significant difference in the amount of cresol attached to lignin in LP1 and LP2, both being 26±1%. The yields of lignophenols for LP1 and LP2 were almost similar at a value of 61±1%. TMA curves showed that LP1 and LP2 had an apparent change of phase at 166.4ºC and 160ºC, respectively