Advancements in the synthesis of furfural and phenol from lignocellulosic biomass utilizing waste-derived or naturally occurring catalysts: A mini review

The majority of lignocellulosic biomass is composed of hemicellulose and lignin, which can be efficiently removed by chemical pretreatment with moderate acid catalysts. The production of furfural and phenol from the recovered hemicellulose and cellulose in the presence of a catalyst is an emerging area. Phenol, which is made from lignin, has many industrial uses, and furfural, which is synthesized from hemicellulose, is widely utilized in pesticides, fertilizers, adhesives, and oil refining. The utilization of conventional acid/alkaline catalysts in this production process has limitations, including reactor corrosion, lack of catalyst regeneration, lignin complexity, and high costs. For the development of low-cost biorefineries, it is essential to replace these conventional catalysts with waste-derived compounds to synthesize furfural and phenol. Hence, this review investigates the application of new catalytic systems (highly selective, low energy requisites, and high basicity) made from waste materials (such as limestone, biomass, and shells) as economical and sustainable substitutes in the production of furfural and phenol. Intensified pretreatment techniques for effective recovery of hemicellulose and lignin are also covered in the review.