Carbon recovery from wasted aqueous-phase bio-oil to fuel precursors through aldol-condensation reaction: A comprehensive review

The aldol condensation reaction, capable of forming new C-C bonds from small molecular carbonyl compounds, is gaining attention again for biogenic carbon recovery from discarded aqueous-phase pyrolysis oil of wood to bio-fuels. This comprehensive review describes the aldol condensation reaction based on the literature review and density functional theory studies to efficiently produce biofuel precursors from complex aqueous phase pyrolysis oil and examines the unavoidable effects of water and acid contained in feedstocks on the aldol condensation reaction and catalyst, as key barriers. Additionally, the newly proposed aldol condensation reaction system and recent advances in tandem catalysts are addressed.