Production of sugar alcohols from real biomass by supported platinum catalyst

• Hydrolytic hydrogenation of real biomass.
• Production of sorbitol and xylitol.
• Reduction of cellulose reactivity by lignin.
• Base catalysis for side-reactions of sugar compounds.
• Alkali-explosion for removal of lignin and inorganic salts.

The influence of lignin and inorganic salts on the catalytic activity was studied in the hydrolytic hydrogenation of real biomass by a supported Pt catalyst. The direct conversion of raw silver grass by Pt/carbon catalyst under H2 pressure produced small amounts of sorbitol (2.8 wt%), xylitol (7.3 wt%), and other sugar alcohols. It has been suggested that lignin reduces the reactivity of cellulose, as lignin exists together with cellulose in the biomass and both compounds are insoluble in water. Moreover, even weak bases drastically change the product distribution with more by-products such as EG and PG. Bases enhance the decomposition of sugar intermediates and sorbitol. The removal of lignin and inorganic salts by alkali-explosion and neutralization raises the contents of cellulose and hemicellulose, thus increasing the yields of sorbitol (13 wt%) and xylitol (14 wt%) in the hydrolytic hydrogenation reactions.

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