# Selective Dehydration of Pentoses and Hexoses of Ulva rigida to Platform Chemicals Using Nb2O5 and ZrO2 Supported on Mesoporous Silicas as Heterogeneous Catalysts

## TL;DR

This paper explores using metal oxide catalysts on mesoporous silicas to efficiently convert sugars from green algae into valuable chemicals.

## Contribution

The study introduces new heterogeneous catalysts for selective dehydration of sugars from Ulva rigida into platform chemicals.

## Key findings

- HMS-supported Nb2O5 achieved 77.8% furfural yield after 4 hours at 180°C.
- The catalysts showed high stability and could be reused up to five times with minimal performance loss.

## Abstract

Furfural and 5-hydroxymethylfurfural are considered as essential platform molecules for the chemical industry, acting as precursors and intermediates of numerous products. They are produced from pentoses and hexoses, respectively, in an acid medium. In this work, biomass from a green macroalgae, Ulva rigida, was treated under acidic conditions provided by heterogeneous catalysts in order to promote the dehydration of its monosaccharides into furfural and 5-hydroxymethylfurfural. Particularly, two functionalized mesoporous silicas, HMS and SBA-supported metal oxides (Nb2O5 and ZrO2), were used as catalysts. Their textural, structural, and acid properties were deeply studied, providing excellent BET surface areas (ranging 424 to 1204 m2/g) and a high concentration of acid sites (220–460 µmol/g), which then translated into great catalytic performances (77.8% and 64.1% of furfural and HMF molar yields, respectively, using HMS-Nb) after a 4 h of reaction time at 180 and 160 °C, respectively. The catalyst showed excellent stability and recyclability as it could be reused for up to five reaction runs with only a slight decrease in performance.