Polyvinyl Alcohol Functionalized Solid Acid Catalyst DICAT‐1 for Microwave‐Assisted Synthesis of 5‐Hydroxymethylfurfural in Green Solvent

Abstract

AbstractMicrowave‐assisted cyclodehydration of fructose to 5‐hydroxymethylfurfural (5‐HMF) was studied herein over polyvinyl alcohol (PVA)‐functionalized solid acid catalyst DICAT‐1 in low‐boiling green solvents. Of the tested solvent systems [isopropanol (IPA), tert‐butyl alcohol, THF, acetone, CH3CN, DMF, and DMSO], IPA was the preferred low boiling point (LBP) reaction medium, resulting in 95 % fructose conversion and 85 % 5‐HMF yield in 120 s. The characteristic dispersibility and swelling properties of DICAT‐1 in IPA had a significant effect on 5‐HMF yield. The catalyst DICAT‐1 was stable and robust under the reaction conditions and easily recycled. The structural and morphological characteristics of the catalyst were elucidated by FTIR spectroscopy, SEM/energy‐dispersive X‐ray spectroscopy, X‐ray fluorescence spectroscopy, XRD, and N2 sorption analysis. DICAT‐1 has covalently bonded −SO3H active sites, an amorphous nature, and mesoporous surface morphology; these features result in excellent performance in IPA. Estimated values of turnover number, turnover frequency, E‐factor, and process mass intensity categorize the overall process as environmentally safe for the production of 5‐HMF. A catalytic mechanism for 5‐HMF formation on DICAT‐1 is proposed.