Process intensification via catalytic one-pot conversion of hemicelluloses to sugar alcohols

The growing use of plant biomass as resource for energy harvesting or feedstock for 'green' processes requires a better understanding of fundamental reaction mechanisms during the different conversion steps. Difficulties exist due the strong heterogeneity of this renewable resource, which mainly consists of cellulose, lignin and hemicelluloses. This work focuses on the conversion of hemicelluloses, because they are still underrepresented in recent scientific works, compared to the more prominent cellulose or lignin. However, hemicelluloses can make up to 35 % of biomass content and are therefore an attractive feedstock from non-food plant biomass (e. g. wood, grass). Target products are sugar alcohols, which have applications in chemical, food, pharmaceutical and cosmetic industry. One of these polyols is xylitol (E 967), a sugar substitute with anti-cariogenic effect. The production of sugar alcohols is typically realized by at least two process steps: first, cellulose or hemicelluloses are cleaved down to their monomeric sugar contents. These monomers are then further refined by catalytic hydrogenation to sugar alcohols. The overall aim of this research work was to investigate the process intensification via merging the two typically separate processes into one process and system ('one pot'). The scientific work should contribute to a deeper and better understanding of the reaction network and deliver parameter recommendations for an efficient 'one pot' process. The results of this thesis help to understand and describe the reaction network during conversion of hemicelluloses to sugar alcohols in 'one-pot' processes. This work covers hydrolysis, hydrolytic hydrogenation & transfer-hydrogenation, kinetic modeling and a novel combination of bio- and chemo-catalysis.