Sulfonic acid-functionalized covalent triazine framework as an efficient and reusable nano-catalyst for dehydration of fructose into 5-hydroxymethylfurfural

Abstract

A novel covalent triazine framework with sulfonic acid functionality (CTF-SO₃H) was synthesized through post-synthetic modification of organic linkers within the CTF using chlorosulfonic acid. The synthesized CTF-SO₃H was evaluated as a solid acid nano-catalyst for fructose dehydration to 5-hydroxymethylfurfural (HMF). Optimization using Response Surface Method (RSM) revealed that optimal conditions of 40 wt% catalyst, 110 °C, and 40 min yielded an impressive 97 % HMF in DMSO. The concentration of –SO₃H in CTF-SO₃H impacted the catalytic activity of CTF-SO₃H nano-catalyst and an improvement was found with increasing –SO₃H grafting level. Kinetic studies indicated that the CTF–SO₃H–mediated fructose-to-HMF dehydration likely follows pseudo-first-order kinetics with a low activation energy of 12 kJ. mol⁻¹ under the studied optimum conditions. Additionally, CTF-SO₃H functions as a heterogeneous catalyst, allowing easy recovery and reuse. This research demonstrates the potential of CTF-derived solid acid catalysts for valorizing biomass carbohydrates.