Effect of Microwave Irradiation on the Catalytic Activity of Tetragonal Zirconia: Selective Hydrogenation of Aldehyde

Tetragonal zirconia was synthesized through microwave modified method and screened for the model reaction (hydrogenation of octanal to octanol) in self-design microwave reactor in a solvent-free system. The catalyst shows microwave cooperative activity with high selectivity toward desire products. The same reaction was also performed under conventional heating system in Parr reactor. The microwave protocol was found more effective in term of conversion and selectivity under optimal reaction conditions. The enhance activity is due to enormous reducing sites production on the surface triggered by microwave irradiation. Here, the mechanism of acidic site population on the surface was comprehensively investigated and correlated with catalyst efficiency. The gas chromatographic studies revealed the formation of octanol as a major product while other small peaks reflect the formation of byproducts C16 aldol, C16 α, β-unsaturated aldehyde and C24 acetal. Thus, the tetragonal zirconia can be used for the conversion of aldehyde to alcohol under microwave irradiation efficiently.