Post-functionalized cellulose/metal-organic framework composite with sulfonic acid: An efficient, rapid and recyclable bio-based solid acid catalyst for the synthesis of 5-hydroxymethylfurfural.

A new acid catalyst derived from renewable sources was developed using an ultrasound-assisted approach. This involved the formation of a metal-organic framework called MIL-88(Fe) in the presence of carboxymethylated-cellulose (CMC). Subsequently, the catalyst underwent a post-synthetic modification to introduce further acidic -SOH groups into the structure of the CMC/MIL-88(Fe) composite. Various examinations were carried out that validated the successful creation of the CMC/MIL-88(Fe)-SOH catalyst. The effectiveness of the catalyst was assessed in the process of solid acid catalysis, specifically in the dehydration of fructose to produce 5-hydroxymethylfurfural (HMF). Through the employment of Response Surface Method (RSM) optimization, it was determined that utilizing 34 wt% of the catalyst at a temperature of 90 °C for 30 min resulted in a remarkable 98 % HMF yield. The catalyst exhibited good reusability, as it retained its catalytic effectiveness throughout four consecutive cycles. Comparative catalytic investigations involving CMC and CMC/MIL-88(Fe) composite without sulfonation revealed the superior activity of CMC/MIL-88(Fe)-SOH catalyst, emphasizing the collaborative effect of CMC, MIL-88(Fe), and the impact of post-functionalization with -SOH on the performance of the catalyst.