1.3.1 METHOD

1.3 WP1.2 Chemocatalytic conversion of biomass-based sugars to

lactic acid

1.3.1 METHOD

This part of the work package aimed for the chemically catalyzed conversion of biomass-based sugars to biochemicals, i.e. lactic acid or ethyl lactate. Selected raw materials were glucose, fiber sludge, fiber sludge hydrolysate and spruce hydrolysate. Fiber sludge was provided by Domsjö Fabriker AB, fiber sludge hydrolysate by RISE Processum AB and spruce hydrolysate by Sekab AB. The project was started with the development of an analytical method (HPLC-RI, Pirttimaa 2020) for the analysis of biochemicals as well as sugars. Also, the chemical composition of the fiber sludge was determined (Lappalainen et al., 2019).

Conversion of raw materials to biochemicals was studied with 1-step conversion reaction performed in a pressure reactor (HEL’s DigiCAT, Figure 12) or in a microwave reactor (Biotage Initiator, Figure 13). Heterogeneous activated carbon-supported metal oxide catalysts or homogeneous metal chlorides or sulfuric acid were used to catalyze the reactions. Water or ethanol was used as the solvent for the conversion reactions. Reaction products were analyzed with HPLC-RI, HPLC-PDA or GC-MS. Schematic representations of the studied reactions are presented in Figures 12 and 13.

Figure 12. Chemical conversion of biomass to biochemicals in pressure reactor catalyzed by activated carbon supported catalysts. Water or ethanol was used as the solvent

Figure 13. Chemical conversion of biomass to biochemicals in microwave reactor catalyzed by Brønsted and Lewis acids. Water was used as the solvent