Biobaserade kemikalier genom fragmentering av skogens råvara med hjälp av fotolys

Important results from the project

The purpose was to investigate whether UV light from LEDs can break bonds in forest raw materials. One goal focused on building photoreactors and we have now three photoreactors with wavelengths of 265, 280 and 310 nm. Another goal was to find the optimal wavelength. Our results on sawdust and technical lignin showed that the formation of platform chemicals depends on the wavelength but also on the solvent. The solvents we have tested so far are water, ethanol, acetonitrile and ethyl acetate. We are currently working on optimizing the solvent and wavelength to increase the yield.

Expected long term effects

Upon exposure of UV light, we observed the formation of formic acid, acetic acid, methanol and aldehydes in sawdust from softwood and technical lignin. The formation of these promising platform chemicals that can substitute their fossil-based counterparts is dependent on the solvent and the wavelength. Our current focus is now on to optimize these parameters to increase the yield. To further enhance the reactions, the use of photocatalysts will be investigated.

Approach and implementation

Sawdust fractions with a narrow size distribution and technical lignin (Kraft and Organosolv) were dispersed in different solvents. UV light of 265, 280 and 310 nm was transported into the reaction vessel using optical fibers. To optimize the exposure of UV light, the dispersions were stirred during the reaction. The solutions were analysed with FTIR, UV, GCMS and NMR and the solid sawdust material with solid-state NMR. We are currently looking into other techniques that could be useful to further analyze and quantify the formed reaction products and to follow the reaction in real-time.