# Chromium-Doped Biomass-Based Hydrochar-Catalyzed Synthesis of 5-Hydroxymethylfurfural from Glucose

## TL;DR

This study explores using chromium-doped hydrochar catalysts to efficiently convert glucose into HMF, a valuable chemical, with the best performance from a bagasse-derived catalyst.

## Contribution

The novel contribution is the development of Cr-doped biomass-based hydrochar catalysts for high-yield HMF synthesis from glucose.

## Key findings

- Cr5BHC180 from bagasse achieved a 64.5% HMF yield under optimized conditions.
- Catalyst activity declined after four cycles due to pore blockage and acid site coverage.
- Regeneration via calcination restored HMF yield to 50.5%.

## Abstract

5-Hydroxymethylfurfural (HMF) is a versatile carbohydrate-derived platform chemical that has been used for the synthesis of a number of commercially valuable compounds. In this study, several chromium (Cr)-doped, biomass-derived hydrochar catalysts were synthesized via the one-pot method using starch, eucalyptus wood, and bagasse as carbon sources. Then, the performance of these synthesized materials for the catalytic conversion of glucose into HMF was evaluated by, primarily, the yield of HMF. The synergistic interactions between the Cr salt and the different biomass components were investigated, along with their effects on the catalytic efficiency. The differences in the catalytic activity of the synthesized materials were analyzed through structural characterization, as well as assessments of the acid density and strength. Among the catalysts, Cr5BHC180 derived from bagasse presented the highest activity, achieving an HMF yield of 64.5% in an aqueous solvent system of dimethyl sulfoxide (DMSO) and saturated sodium chloride (NaCl) at 170 °C after 5 h. After four cycles, the HMF yield of Cr5BHC180 decreased to 38.7%. Characterization techniques such as N2 adsorption–desorption and Py-FTIR suggested that such a decline in the HMF yield is due to pore blockage and acid site coverage by humic by-products, as demonstrated by the fact that regeneration by calcination at 300 °C restored the HMF yield to 50.5%.