Sustainable Synthesis of Drop-In Chemicals from Biomass via Chemical Catalysis: Scopes, Challenges, and the Way Forward

A handful of small organics, namely, ethylene, propylene, butadiene, benzene, toluene, xylenes, and methanol, produced from petroleum and other fossilized carbon-based resources, can produce practically all petrochemicals and synthetic organic polymers used in the industrialized societies. The molecules mentioned above, often referred to as primary petrochemicals, must be sourced from renewable carbon feedstock to achieve the long-aspired all-around sustainability in chemical manufacturing. Significant efforts have been devoted to developing efficient chemical–catalytic pathways for selectively converting biomolecules and biopolymers into these petroleum-derived chemical platforms. The processes take advantage of prevalent petrorefinery infrastructure, well-documented synthetic value addition pathways of the chemical platforms, and established markets of the derived products. Relative merits and demerits of various catalytic routes in producing the aforementioned primary petrochemicals from renewable biomass have been deliberated. This review elaborates on the synthetic methodologies available for synthesizing the drop-in replacement of primary petrochemical from renewable biomass, focusing on process selectivity, feedstock selection, and catalyst performance. The critical analyses presented in this review will assist in appraising the research accomplishments to date, identifying the bottlenecks, and realigning the future perspectives.