FACILE PRODUCTION OF 4-HYDROXYBENZOIC ACID FROM OIL PALM EMPTY FRUIT BUNCH CELL WALLS BY ALKALI DEGRADATION AT ROOM TEMPERATURE

Abstract

Oil palm empty fruit bunches are biorefinery waste produced from the oil palm factory. Palm lignin is partially ended with p-hydroxybenzoylated structure, which is a promising resource to produce 4-hydroxybenzoic acid. Herein, 4-hydroxybenzoic acid is produced by the degradation of oil palm empty fruit bunch cell walls with sodium hydroxide solution at room temperature without lignin isolation. The 4-hydroxybenzoic acid was obtained as the only main monomeric product from the process. The yield of 4-hydroxybenzoic acid can reach 7.87% based on the amount of oil palm empty fruit lignin. The sodium hydroxide concentration is the most important factor that affects the 4-hydroxybenzoic acid production yield and selectivity. The possible 4-hydroxybenzoic acid production routes were proposed. And the production route is considered to be formed mainly by the cleavage of C-O bonds at the γ-hydroxyl position of the syringyl unit in oil palm empty fruit bunch lignin.