Catalytic Synthesis of Imines from Alcohols and Amines

The catalytic synthesis of imines via direct coupling of alcohols and amines has emerged as a sustainable and atom-economical route to value-added compounds. In this tandem process, an alcohol is initially dehydrogenated to the corresponding aldehyde, which then condenses with an amine to form an imine, liberating hydrogen and water as benign by-products. A wide range of heterogeneous catalysts, including transition metal oxides, supported noble metals and magnetic composites, have been engineered to combine redox activity with surface acid-base functionality. Key design parameters include the density of oxygen vacancies, the balance of acidic and basic sites and the metal-support interaction that promotes efficient hydrogen release and subsequent C–N bond formation. Recent advances have further exploited plasmonic excitation and microwave-assisted synthesis to enhance reaction rates under mild conditions. Such developments not only lower energy demands and simplify catalyst recovery but also enable selective transformations under solvent-free or aqueous media. The broad applicability of this methodology spans pharmaceutical intermediates, agrochemical precursors and fine chemicals, underscoring its global significance in green chemical production.

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Catalytic Synthesis of Imines from Alcohols and Amines publication trend

The graph below shows the total number of articles in catalytic synthesis of imines from alcohols and amines across all publications each year (not limited to Nature Index journals).

Technical terms

Acceptorless dehydrogenation: Catalytic removal of hydrogen from a substrate without the need for an external acceptor, producing H₂ as a by-product.

Oxygen vacancy: A point defect in metal oxide lattices where an oxygen atom is absent, creating active sites for adsorption and redox reactions.

Localized surface plasmon resonance (LSPR): Collective oscillation of conduction electrons in metal nanoparticles under light excitation, enhancing electromagnetic fields at the surface.

Acid–base bifunctionality: The presence of both acidic and basic sites on a catalyst surface, enabling sequential activation of reactants.

Turnover frequency (TOF): The number of substrate molecules converted per active site per unit time, a measure of catalytic efficiency.

Redox cycling: Repetitive oxidation and reduction of a catalyst’s surface, facilitating electron transfer and continuous reaction turnover.

References

1. Microwave-Assisted Solvothermal Synthesis of Fe3O4/CeO2 Nanocomposites and Their Catalytic Activity in the Imine Formation from Benzyl Alcohol and Aniline. Catalysts (2020).
2. CeO2 Structure Adjustment by H2O via the Microwave–Ultrasonic Method and Its Application in Imine Catalysis. Frontiers in Chemistry (2022).
3. Hot Electrons, Hot Holes, or Both? Tandem Synthesis of Imines Driven by the Plasmonic Excitation in Au/CeO2 Nanorods. Nanomaterials (2020).