Hydrothermal Carbonization of Glucose, Fructose, and Xylose—Identification of Organic Products with Medium Molecular Masses

Abstract

The monosaccharides glucose, fructose, and xylose were subjected to hydrothermal carbonization in aqueous solution at temperatures of 180, 220, and 250 °C for different operating times (30 min to 16 h). Here, 68% to 78% of the organic carbon was converted into hydrochar at 220 °C with glucose and fructose as feedstock, whereas hydrothermal treatment of xylose did not result in significant hydrochar formation under these conditions. The main topic of this contribution was the identification of stable organic products in the process water in the molecular mass range between 120 and 300 Da by means of GC-MS analysis using several derivatization agents. Special attention was paid to polar OH- and COOH-functionalized compounds. The overwhelming majority of identified organic compounds had cyclic structures of which a prominent group included hydroxylated benzofurans. However, the combined yield of products, which might be potential substrates for liquid biofuels, turned out very low.

An evaluation of subcritical hydrothermal treatment of end-of-pipe palm oil mill effluent

“…It is generally accepted that the exothermic reaction which lowers the molecular O/C and H/C ratio is mainly caused by dehydration and decarboxylation (Funke and Ziegler, 2010). This is also in good agreement to the reactions reported by Poerschmann and the team (Poerschmann et al., 2017). The C content of the hydrochar produced was in the range from 55.47% to 66.23% and it was comparable with the C content (20%–78%) of the hydrochar derived from hydrothermal treatment of other compounds (Berge et al., 2011).…”

Biobased Functional Carbon Materials: Production, Characterization, and Applications—A Review

“…Hemicellulose and cellulose are hydrolyzed into simple sugars, which in turn are converted into hydroxymethylfurfural (HMF) via dehydration reaction [ 36 ]. Subsequently, HMF can follow two paths: either it is decomposed into formic and levulinic acid or it polymerizes to form hydrochar via water elimination, aldol condensation and Diels-Alder addition reactions [ 37 ]. There is clear evidence that supports the catalytic effect of protons on the HMF production [ 38 ].…”

Identification of the Soluble Byproducts Formed during the Hydrothermal Conversion of Cellulose Catalyzed by Solid Tungstated Alumina

“…The C atoms of these detected compounds were in the range of 3–12, and the O atoms were in the range of 3–6, quite similar to the soluble compounds formed during the hydrothermal carbonization of glucose. 22 , 28 …”