O-27　Investigation on the utilization of lignin obtained by a pretreatment of palm empty fruit bunches with aqueous maleic acid/n-butanol solution

Abstract

The chemical structure and physical properties of the lignin fraction obtained by the pretreatment of palm empty fruit bunches (EFB), an agricultural waste of the palm oil industry, were evaluated in this study. The pretreatment was performed in a two-phase system with aqueous maleic acid and butanol at 180°C. The extracted lignin was quantitatively soluble in organic solvents such as acetone due to the butylation during pretreatment. The weight average molecular weight decreased from 6,400 to 1,200 with increasing pretreatment time up to 45 min. The concentration of aliphatic hydroxyl groups was low (0.99 mmol/g), comparing with the relatively high concentration of aromatic hydroxyl groups (2.24 mmol/g). Selective esterification of aliphatic hydroxyl groups in the lignin molecule was performed by a catalysis of ionic liquid: 1-ethyl-3-methylimidazolium acetate (EmimOAc). We found that the solubility in organic solvents could be adjusted while remaining a large amount of aromatic hydroxyl groups.