Carrageenan-based green heterogeneous catalyst for production of 5-hydroxymethylfurfural by dehydrating fructose and glucose, M Rezaie, M Dinari, AN Chermahini, M Saraji, A Shahvar Biomass Conversion and Biorefinery,  1-13, 2021

In this research, iota carrageenan (ιC) was cross-linked with N, N-methylene bisacrylamide (MBA) to form ιC-g-MBA, as a new green solid acid catalyst. The catalyst structure and morphplogy were explored using FT-IR, TGA, BET, FESEM, and XRD techniques. It was used in 5-hydroxymethylfurfural (5-HMF) production by fructose and glucose dehydration. Factors contributing to reaction optimization, such as the solvent, temperature, catalyst amount, and reaction duration, were explored. The optimal conditions of the reaction for fructose dehydration were 160 °C and 1 h as the reaction temperature and time, respectively. It was established that the conversion of fructose and HMF yield was 95.5% and 93.1%, respectively. Similarly, the optimal temperature and time for the reaction of glucose dehydration were 160 °C and 2 h, respectively. Moreover, the HMF yield and glucose conversions were 46% and 93%. Reusability of the catalyst was analyzed, whereupon the catalyst proved capable of being reemployed after four runs.

https://link.springer.com/article/10.1007/s13399-021-02117-1