Advances in 5-hydroxymethylfurfural production from biomass in biphasic solvents

Biomass derived 5-hydroxymethylfurfural (HMF) has emerged as an important platform chemical for the production of value added chemicals and liquid fuels that are currently obtained from petroleum. Although a significant amount of research has been performed over the past decade, the high production cost of HMF is still a bottleneck for its sustainable utilization for making other value added chemicals and fuels on a commercial scale. Among several factors, low product selectivity and high purification cost are major constraints. To address these drawbacks, HMF production methodology in recent years has been directed towards utilization of biphasic media for concurrent extraction of HMF into an organic phase immediately after its formation in the reactive phase. As a result, several dozens of journal and patent articles have appeared, demonstrating the benefit of biphasic media for effective HMF extraction. This review article summarizes the findings of the most recent research articles with critical discussion on the factors that enhance the performance of biphasic media. Particular emphasis has been given to the development of more effective extracting solvents and their beneficial effect in enhancing HMF yield and selectivity, improvement of partition coefficient, mechanistic role of the bi-functional acid catalysts and factors that control high HMF selectivity for solid catalysts.