Abundant waste agricultural residues such as oil palm empty fruit bunch (EFB) can provide alternative sources of biomass for producing furfural. The aims of this study were to propose a method of preparing furfural and dissolving pulp (DP) from EFB using prehydrolysis with nitric acid, and to examine how the prehydrolysate, which contains xylan, can be used for furfural production. The furfural yield in the nitric acid prehydrolysate was increased to 6.2% of the EFB material weight by dehydration with an acid catalyst. Nitric acid prehydrolysis followed by soda cooking under atmospheric pressure was also applied to the preparation of DP. The obtained pulp was then bleached by using peroxymonosulfuric acid (Psa), chlorine dioxide (D0, D1), and hydrogen peroxide (Ep) in the elementary chlorine-free Psa-D0-Ep-D1 sequence. The pulp demonstrated a brightness of 90.4% ISO and a viscosity of 6.5 cP, which met the National Standard of Indonesia, although the xylan content was a little high and the α-cellulose content was 83.0%.

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The process of prehydrolysis followed by soda-anthraquinone (AQ) cooking and totally chlorine-free (TCF) bleaching with peroxymonosulfuric acid (P sa ) was investigated to develop a biorefinery process. Eucalyptus globulus, showing a high syringaldehyde (S a ) to vanillin (V a ) molar ratio after nitrobenzene oxidation, was utilized. Xylooligosaccharide yield in the prehydrolysate (PHL) obtained at 150 °C for 2.5 h reached 7.2% of wood weight, indicating 47% extraction of xylan. Furfural yields increased with acid catalytic dehydration of the PHL to 1.0-1.8% of wood weight; adding an earlier acid post-hydrolysis of the PHL to generate monomeric xylose enhanced furfural production to 4.0%. Soda-AQ cooking, a non-sulfur process affording simpler alkali lignin isolation than kraft cooking, was utilized. Active alkali dosage increment decreased both S a to V a molar ratio (S/V ratio) and S a and V a yields of dissolved lignin. Gel permeation chromatography indicated decreased or increased purified lignin weight-average molecular weight (M w ) upon increased active alkali dosage or prehydrolysis temperature, respectively (e.g., 150 to 170 °C at 18% alkali increased M w 1653 to 2050). Chlorine dioxide (0.083% and 0.042% as active chlorine) inclusion during the 1st and 2nd P sa stages with P sa (0.2% and 0.1% as H 2 SO 5 weight, respectively) improved final bleached pulp viscosity from 6.0 to 7.2 mPa s.

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