Fractionation of lignocellulosic biomass using the OrganoCat process

Abstract

The fractionation of lignocellulose in its three main components, hemicellulose, lignin and cellulose pulp can be achieved in a biphasic system comprising water and bio-based 2-methyltetrahydrofuran (2-MeTHF) as solvents and oxalic acid as catalyst at mild temperatures (up to 140°C). This so-called Organo-Cat concept relies on selective hemicellulose depolymerization to form an aqueous stream of the corresponding carbohydrates, whereas solid cellulose pulp remains suspended and the disentangled lignin is to a large extent extracted in situ with the organic phase. In the present paper, it is demonstrated that biomass loadings of 100 g L −1 can be efficiently fractionated within 3 h whereby the mild conditions assure that no significant amounts of by-products (e.g. furans) are formed. Removing the solid pulp by filtration allows to re-use the water and organic phase without product separation in repetitive batch mode. In this way, (at least) 400 g L −1 biomass can be processed in 4 cycles, leading to greatly improved biomass-to-catalyst and biomass-to-solvent ratios. Economic analysis of the process reveals that the improved biomass loading significantly reduces capital and energy costs in the solvent recycle, indicating the importance of process integration for potential implementation. The procedure was successfully scaled-up from the screening on bench scale to 3 L reactor. The feedstock flexibility was assessed for biomasses containing moderate-to-high hemicellulose content.

Paving the Way for Lignin Valorisation: Recent Advances in Bioengineering, Biorefining and Catalysis

“…[224,235] The" Organocat" process seems to overcome this constraint, whereby fractionation of lignocellulose occurs via the initial oxalic/formic acid-catalysed shellpeeling of lignin and hemicelluloses,i nabiphasic 2-methyltetrahydrofuran/water system. [236,237] Lignin and hemicellulosic fragments are thus immediately partitioned into organic and aqueous phases,r espectively,u pon liberation from the …”

“…In this manner,t he cellulose could be isolated as ap ale yellow solid. [236,237] Organosolv processes may also be performed in the absence of an added acid, with good delignification results. [212, 238.…”

Fractionation for further conversion: from raw corn stover to lactic acid

“…For the possibility to avoid harsh conditions (e.g. strong acids or alkaline) and complex processes, organic acid-catalyzed organosolv methods are promising to fractionate the three components in a more economical and environmentally friendly way1314. Typically, a so-called “organocat process” was reported by Leitner et al ., in which oxalic acid selectively catalyzed the depolymerization of hemicellulose and the dissolution of lignin in a 2-methyltetrahydrofuran-water biphasic system15.…”

Cellulose acetate as a convenient intermediate for the preparation of 5-acetoxymethylfurfural from biomass

“…8 Therefore, in order to evaluate the possible integration of this process into a biorefinery scenario, AMF production by treatment of cellulose acetate obtained by different biomass fractionation schemes was evaluated. Commercial cellulose, Organocat pulp 26 and crude beech wood were acetylated (for details see the ESI †) and used for this purpose. Unlike the case of commercially available cellulose acetate, cellulose acetates with DS >2 were obtained (Table 1) via acetylation, as confirmed by NMR spectroscopy (S1-3 †).…”