Insights into Microwave-Assisted Synthesis of 5-Ethoxymethylfurfural and Ethyl Levulinate Using Tungsten Disulfide as a Catalyst

Microwave-assisted synthesis of 5-ethoxymethylfurfural (EMF) and ethyl levulinate (EL) in the presence of tungsten disulfide has been studied for the first time. The catalyst was synthesized at 600 °C in a tubular furnace using elemental tungsten and sulfur to obtain multilayered flakes/sheets of WS2. The textural and morphological properties of the synthesized WS2 catalyst were characterized using XRD, Raman, SEM, SEM-EDX, TEM, TEM-EDX, HR-TEM, SAED, and surface area analyzer, which showed the formation of multiple two-dimensional layers of sheet/flake-type structure. Activity test of the catalyst in a microwave-assisted reaction resulted in 100% fructose conversion and 62% EMF yield for the experiment performed at 160 °C temperature in 15 min. A qualitative analysis of the product samples using GC-MS spectrometry showed the presence of several intermediates and byproducts based on which a mechanistic insight into the production of EMF from fructose has been proposed.