Abstract

The most effective parameters for the synthesis of Carbon Dots (CDs) obtained from Water Hyacinth (WH) were found to be 125 ̊C, 35 minutes, and 7 g, with a maximum yield of 18.65%, according to the Design Expert 13.0 program. The phosphonated solid acid catalyst (PCDs) was synthesized by functionalizing CDs with concentrated phosphoric acid (85%) at 150 ̊C for 6 hours and used as a catalyst for producing 5–hydroxymethylfurfural (5-HMF). UV, XRD, SEM, FTIR, TGA elemental analysis, and acid–base titration techniques were used to characterize the CDs and catalyst. The FTIR spectra confirm the synthesized catalyst exhibited functional groups such as -PO3H2, -COOH, and -OH. The Catalytic Performance of PCDs was evaluated in the one-step Microwave-Assisted (MW) conversion of WH into 5-HMF using a biphasic solvent (isopropanol: water), achieving a 73.05% yield at 90 ̊C in 40 minutes using 0.6 g of catalyst. For using crude biomass in 5-HMF production this method offers a green and efficient approach.