Oxidation of 5-hydroxymethylfurfural into 2,5-furandicarboxylic acid over CuO and NiO modified natural sourced hierarchical ZSM-5

Abstract

The platform molecule 2,5-furandicarboxylic acid (FDCA) has potential applications. FDCA can be synthesized through the oxidation of 5-hydroxymethylfurfural (HMF). In this study, HMF oxidation to FDCA was conducted over ZSM-5-based catalysts from natural sources. ZSM-5 was impregnated with CuO and NiO oxide metals to increase their acidity and oxidizing ability. Characterization of the catalyst utilizing x-ray diffraction (XRD), infrared spectrophotometer (FT-IR), scanning electron microscopy-energy dispersive x-ray (SEM-EDX), Brunauer-Emmet-Teller (BET) surface area analysis, and temperature-programmed desorption of ammonia (NH3-TPD) led to the discovery of its physicochemical characteristics. The results showed that synthesized ZSM-5 had hierarchical pores with a surface area of 123.58 m2/g. Impregnation with CuO and NiO increased the acidity by 22.5 and 3.04 % for CuO/ZSM-5 and NiO/ZSM-5, respectively. In a small glass batch reactor, HMF was converted to FDCA, and the products were analyzed using High-Performance Liquid Chromatography (HPLC) to determine the yield of FDCA and the intermediate compounds, such as 5-hydroxymethylfuroic acid (HMFCA), 5-formylfuroic acid (FFCA), and 2,5-diformylfuran (DFF). HPLC results showed no DFF signal, indicating the formation of FDCA from HMF through HMFCA and FFCA. The highest conversion (99.2 %) was obtained using a NiO/ZSM-5 catalyst at a temperature of 130 °C for 4 h, with FDCA yield of 88.9 %.