Xylose, conversion into furfural

In the presence of the H-Mordenite with a Si/Al ratio of 11 as catalyst, a close parallelism is observed with the results obtained for the dehydration of fructose, except that toluene is the co-solvent instead of methyl isobutyl ketone. The transformation of xylose into furfural is easily achieved at 170 °C with a selectivity as high as 90 to 95% as far as the conversion is kept at a low extent, 30 to 40%.[33] At those high temperatures, ion-exchange resins cannot compete with zeolites. 

Although abundant in nature, and although several opportunities have been identified [64], heteropolysaccharides have largely escaped industrial exploitation. Exceptions are the conversion of pentoses into furfural (for temperature-resistant foundry resins) by acid hydrolysis the fermentation of pentoses into single cell protein Torula yeast) the catalytic reduction of xylose to xylitol, a dietary sweetener and the use of larch [Larix sp.)-specific arabinogalactan extracts as dispersants in printing inks. 

An example hereof is the isomerization of xylose with Sn-beta into xylulose and lyxose (27% and 11% yield respectively at 60% xylose conversion). When Br0nsted acids are added to the Sn catalyst, furfural can be formed in a single pot (vide infra) [57]. 

Zhang J, Zhuang J, Lin L, Liu S, Zhang Z. Conversion of D-xylose into furfural with mesoporous molecular sieve MCM-41 as catalyst and butanol as the extraction phase. Biomass Bioenergy 2012 39 73-7. 

Yemi , O., Mazza, G., 2011. Acid-catalyzed conversion of xylose, xylan and straw into furfural by microwave-assisted reaction. Bioresource Technology 102 (15), 7371-7378. 

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