Catalysts Fe-SBA-15 for depolymerization of hemicellulose

Iron-containing catalysts based on mesostructured silicate SBA-15 were synthesized via the co-condensation method in an acidic medium (1.6 M HCl) with initial gel Fe/Si molar ratios of 5, 15, and 20%. Powder X-ray diffraction, nitrogen sorption, and electron microscopy confirmed that the synthesized catalysts retain the ordered hexagonal mesostructure characteristic of SBA-15. X-ray fluorescence analysis revealed that the iron content in the final samples does not exceed 0.06 mol%. For pure SBA-15, fiber length is ~2 μm with a thickness of ~0.2 μm. Introducing an iron precursor into the synthetic solution elongated the particles of iron-containing catalysts to 10–30 μm, while thickness remained virtually unchanged. The catalysts were tested in the hydrolysis and oxidation with atmospheric oxygen of soluble hemicellulose sugars from aspen wood, isolated via hydrolytic treatment. The maximum formic acid yield reached 25.8 wt% (150°C, 5 h).