Zr supported on non-acidic sepiolite for the efficient one-pot transformation of furfural into gamma-valerolactone

The growing demand of energy needs the search for alternative energy sources different to fossil fuels. The use of biomass as energy source is one of the most studied, because there are high value products that can be produced from biomass. One of these products is gamma-valerolactone, that can be obtained from furfural, which is a biomass derived product. To transform furfural into gamma-valerolactone is necessary a bifunctional catalyst and a hydrogen source. In this work, gamma-valerolactone was obtained from furfural using 2-propanol as solvent and as hydrogen donor on Zr supported on sepiolite catalysts. It was demonstrated that sepiolite, which is a cheap material, can be used to develop efficient catalysts to produce high yields to gamma-valerolactone from furfural in one-pot. The cat-alysts that presented the highest yield to gamma-valerolactone were the ones with intermediate Zr-content (9-17 wt% ZrO2). The highest TOFs have been obtained by those catalysts with Zr-loading up to 9 wt% ZrO2, in which the ZrO2 nanoparticles are well dispersed on the support and no formation of large clusters of ZrO2 has been observed. Lewis and Bronsted acid sites are essential in the catalysts to produce the reactions to transform furfural into gamma-valerolactone in one-pot, although in the present work, low concentration of Bronsted acid sites were observed in the catalysts. A possible positive role of basic sites to promote some intermediate steps has been also proposed. The catalytic results obtained are in the order of catalysts with Zr supported on zeolitic supports.