Tin, molybdenum and tin-molybdenum oxides: Influence of Lewis and Bronsted acid sites on xylose conversion

• Published in: Catalysis today 2022-07, Vol.394-396, p.125-132
• Main Authors: dos Santos, Thatiane V., da Silva Avelino, Débora Olimpio, Pryston, Dhara B.A., Meneghetti, Mario R., Meneghetti, Simoni M.P.
• Format: Article
• Language: English
• Subjects: Acid sites; Biomass; Catalyst; Impregnation; Mixed oxide; Xylose
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2021.10.018

In this study, tin oxide (SnO2), molybdenum oxide (MoO3) and a mixed oxide based on tin and molybdenum (respectively, Sn100, Mo100 and SnMo25, synthesized by the impregnation method) were applied in xylose conversion. The best results were obtained employing Mo100 and SnMo25. In the presence of SnMo25, after 0.5 h, xylose conversions of 39.5%, 34.1% and 63.4% were obtained, respectively, at 110, 130 and 150 °C. For Mo100, conversions of 49.6%, 71.8% and 85.3% were attained under the same reaction conditions, showing that Mo100 provided the best conversion results. However, with the use of this catalyst there was an increase in the amount of soluble and insoluble polymeric material. In terms of the soluble products formed from xylose, depending on the reaction condition were detected xylulose (X), lyxose (L) and furfural (FUR), glyceraldehyde (GL), pyruvaldehyde (PYR), glycoaldehyde (GLYC), dihydroxyacetone (DHA), lactic acid (AL), levulinic acid (LA) and acetic acid (AA). However, with the use of Sn100 or without a catalyst (systems with low conversions) there was mainly the formation of lyxose. The use of Mo100 and SnMo25 (systems which exhibit high acidity) leads mainly to isomerization, epimerization and dehydration reactions, as in the case of the retro-aldol pathway and furfural conversion, highlighting the importance of Lewis and Bronsted acid sites in relation to modulating the selectivity of the systems. [Display omitted] •Individual and mixed metal oxide of tin and molybdenum were synthesized.•Catalysts were applied in xylose conversion.•Mo100 and SnMo25 lead to best xylose conversion.•Lewis and Bronsted acid sites can modulate the selectivity.