Synthesis and DFT studies of robust heterogeneous Co(III) catalyst for liquid phase oxidation of tetralin

Chitosan based robust heterogeneous catalyst, {Co(III)[Cs-L₁-L₂]Cl₂} was synthesized using two different Schiff base ligands, L₁ [Cs-HACP] and L₂ [ANI-HACP] and CoCl₂·6H₂O metal salt. The synthesized catalyst {Co(III)[Cs-L₁-L₂]Cl₂} was characterized by different analytical techniques like scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), Inductively coupled plasma atomic emission spectroscopy (ICP-AES), Elemental (CHN) analysis, X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area, thermo-gravimetric analysis (TGA), Fourier transform infrared (FTIR), ultraviolet visible near infrared (UV–VIS-NIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Density Functional Theory (DFT) studies. The catalytic performance of {Co(III)[Cs-L₁-L₂]Cl₂} catalyst has been investigated for the oxidation of tetralin using 70% tert-butyl hydroperoxide (TBHP). In the oxidation reaction, tetralin was converted into 1-tetralone, 1-tetralol and some other products. A maximum conversion 84.88% of tetralin with 80.68% selectivity of 1-tetralone (T-lone) and 10.06% selectivity of 1-tetralol (T-lol) was obtained after 6 h at 80 °C. The catalyst was recycled seven times without loss in its catalytic activity. The catalyst {Co(III)[Cs-L₁-L₂]Cl₂} is found to be environmental friendly in nature, easy to separate and recoverable.