The pre-treatment of lignocellulosic biomass produces a liquid stream of hemicellulose-based sugars, which can be further converted to high-value chemicals. Formosolv pulping and the Milox process use formic acid as the fractionating agent, which can be used as the catalyst for the valorisation of hemicellulose sugars to platform chemicals. The objective of this study was to investigate the reaction kinetics of major components in the hemicelluloses fraction of biomass, that is, D-xylose, L-arabinose and D-glucose. The kinetics experiments for each sugar were performed at temperatures between 130 and 170 °C in various formic acid concentrations (10-64 wt %). The implications of these kinetic models on the selectivity of each sugar to the desired products are discussed. The models were used to predict the reaction kinetics of solutions that resemble the liquid stream obtained from the fractionation process of biomass using formic acid.

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10Furfural is a potential platform chemical derived from biomass, which has gained increased 11 attention as a potential substitute for the displacement of petrochemicals and the production 12 of biofuels. The catalytic effect of different metal tri-chlorides (FeCl3, AlCl3 and CrCl3) 13 with formic acid (FA) was investigated for the selective conversion of D-xylose to furfural 14 in aqueous solutions. Reactions were carried out at various temperatures (100-170 o C), FA 15 concentrations (0-65 wt.%), and metal chloride concentrations (0.2-0.8 M). Lyxose was 16 identified as primary intermediate of the conversion of xylose at low temperatures and FA 17 concentrations. A mixture containing 0.4 M AlCl3 and 55 wt.% FA was the most selective 18 and active system for the production of furfural at low temperatures (130 o C, selectivity 19 ≈70-90%). A simplified kinetic model was developed to describe the overall xylose 20 * Corresponding author: Tel.: +353 85 129 68 49. Email address: karla.dussan@nuigalway.ie (K. Dussan) 2 conversion and furfural formation under the selected conditions, offering a valuable tool for 1 process optimisation and design. 2

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A comprehensive study is presented on the conversion of hemicellulose sugars in liquors obtained from the fractionation of Miscanthus, spruce bark, sawdust, and hemp by using formic acid. Experimental tests with varying temperature (130-170 °C), formic acid concentration (10-80 wt%), carbohydrate concentrations, and lignin separation were carried out, and experimental data were compared with predictions obtained by reaction kinetics developed in a previous study. The conversions of xylose and arabinose into furfural were inherently affected by the presence of polymeric soluble lignin, decreasing the maximum furfural yields observed experimentally by up to 24%. These results were also confirmed in synthetic mixtures of pentoses with Miscanthus and commercial alkali lignin. This observation was attributed to side reactions involving intermediate stable sugar species reacting with solubilized lignin during the conversion of xylose into furfural.

Lignin, the second most abundant biopolymer on the planet, has properties that can be widely explored, moving from waste to products with high added value. Therefore, this work aimed to extract and characterize Klason and Kraft lignins from sawdust and black liquor, considered industrial waste. The raw material used was Eucalyptus grandis chips. To obtain Klason lignin according to TAPPI 222 om-02 (2002), part of the chips were transformed into sawdust. To obtain Kraft lignin, another part of the chips passed through a digester to obtain black liquor, which was subsequently subjected to acid precipitation. The characterization of lignins was performed by granulometry analysis, scanning electron microscopy with elemental chemical analysis (EDS), transmission electron microscopy, medium infrared spectroscopy, thermogravimetric analysis and differential calorimetry. Microscopy analyzes showed irregular structures of various shapes, including spherical structures, most evident and frequent in Kraft lignin. The elementary chemical analysis showed that the lignin washing process was satisfactory, due to the small percentage of sulfur detected in the samples. The results of the granulometry confirmed that the lignins had micrometric dimensions. The medium infrared spectra showed the characteristic peaks of the chemical composition of lignin. The thermal analysis showed three ranges of degradation, attributed to the drying of the samples, degradation of the hemicelluloses and the lignin itself. All results confirmed the obtaining of Klason and Kraft lignins. Therefore, the techniques were satisfactory in transforming waste into lignin with the potential for a variety of commercial applications, mainly in the chemical and pharmaceutical industries.

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Cryptomeria japonica is a softwood of Japanese origin known for its versatility wood use. The objective of this work was to characterize the wood of C. japonica for kraft pulping and papermaking. For this, wood chips from a 13-year-old trees of C. japonica and, as reference material, industrial wood chips of Pinus taeda, both from southern Brazil was used. The physical, chemical, fiber dimensions of the woods, the performance of each species in the kraft pulping and the paper physico-mechanical properties was evaluated. The fiber size, wood basic density, extractive content, and holocellulose content of C. japonica were lower than those of P. taeda, on the other hand total lignin and ash in wood were higher. On kraft pulping the performance of the C. japonica wood was superior, with better yields, lower reject content and lower active alkali consumption, despite requiring more active alkali to achieve the desired kappa and presenting higher specific wood consumption. The papers made with the C. japonica pulp presented superior physico-mechanical properties.