Biomass-Derived Carbohydrates to 5-Ethoxymethylfurfural

The synthesis of liquid fuel and fuel additives from abundant biomass substrates has acquired significant attention in recently. Among these value-added chemicals, 5-Ethoxymethylfurfural (5-EMF) is considered one of the most desirable gasoline alternatives because of its high stability, environmental friendliness, and high energy density of 8.7 kWhL⁻¹. This 5-EMF could be directly produced from different biomass or biomass-derived substrates via etherification reactions in ethanol medium by straightforward synthetic methods using homogeneous catalysts and heterogeneous catalysts. In the current review, the role of different starting materials, homogeneous catalysts, and heterogeneous catalysts in the synthesis of 5-EMF is extensively discussed. Furthermore, the effect of different solvent system viz; single-phase, biphasic solvents, ionic liquids, and deep eutectic solvents (DES), on 5-EMF synthesis has also been discussed. The advantages and challenges of the chemocatalytic synthesis of EMF in different reaction systems are also discussed. We also tried to focus on the most economical way to produce EMF from HMF, and the mechanistic studies are summarized here along with catalyst deactivation data.