Tetranuclear Mn(II) substituted sandwich complex as a recyclable homogeneous catalyst for selective oxidation of styrene to benzaldehyde: Effect of reaction parameters and kinetics

•Sandwich type Mn(II) substituted POMs as catalyst for oxidation of styrene.•High selectivity for aldehyde.•Very high activity in terms of TON.•Recyclable homogeneous catalyst.

An attempt has been made to use tetranuclear sandwich type Mn(II) substituted POMs as catalyst for solvent free liquid phase oxidation of styrene under mild reaction conditions. The present catalytic system considered as an efficient and effective approach in achieving high conversion rate with high turnover numbers (TONs) with single selective product (benzaldehyde (BA)). Surprisingly, synthesized complex behaved as homogeneous catalyst under present reaction conditions. An efficient simple approach was introduced to regenerate catalyst and further reuse up to two cycles. Kinetic investigation reveals that the oxidation reaction of styrene follows a first order kinetics in presence of H2O2 as an oxidant. The influence of temperature on rate constant was also studied and the activation energy was found to be 34.1 kJ mol−1.

Graphical abstractAn attempt has been made to use tetranuclear sandwich type Mn(II) substituted POMs as catalyst for solvent free liquid phase oxidation of styrene under mild reaction conditions.Figure optionsDownload full-size imageDownload as PowerPoint slide