Síntese e caracterização de óxidos mistos a base de estanho e nióbio para conversão da frutose em insumos químicos

Abstract

The development of selective and efficient catalytic systems in the transformation of sugars into products of industrial interest have been widely studied, with special attention to heterogeneous catalysts, due to their numerous advantages. In this work, we investigated a series of mono- and/or bimetallic oxides based on Sn and Nb that were synthesized by co-precipitation methods, modeled by surfactant and modified Pechini. The structural, textural and acid-base properties were fully characterized. Among them, the mixed oxides achieved conversions higher than those observed for the pure oxides (SnO2 (CPT) = 58.2 %, Nb2O5 (CPT) = 70.2 %, SnNb (CPT) = 81.3 %; SnO2 (CTAB) = 60.5%, Nb2O5 (CTAB)=75.8%, SnNb (CTAB)= 93.4%; SnO2 (G) = 56.8%, Nb2O5 (G) = 59.6 %, SnNb (G) = 75.7 %; SnO2 (EG) = 48.3 %, Nb2O5 (EG)= 51.6 %, SnNb (EG)= 78.5%). These results were achieved within 6 hours of reaction. The percentages obtained can be justified due to the balance between the Lewis and Bronsted acid sites, which is essential to make these catalysts more versatile for applications in biorefinery processes. Furthermore, the catalysts show promising selectivity to 5-hydroxymethylfurfural (5-HMF). Reuse and leaching tests were also carried out and with the data obtained we can affirm that these systems are robust, remaining stable for four cycles, without structural modifications, which denotes that they are promising in the transformation of carbohydrates. (the formulas that are in the summary cannot be viewed in this field)