Catalytic epoxidation of α-pinene with molecular oxygen using cobalt(II)-exchanged zeolite Y-based heterogeneous catalysts

Abstract

Cobalt cation-exchanged zeolite Y-based catalysts were studied for epoxidation of α-pinene with molecular oxygen in 20–100 psi pressure range using N, N-dimethylformamide (DMF) as a solvent at 373 K. The catalysts characterization with X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS) suggests that cobalt introduced into faujasite zeolite exists in Co(II) state and catalyzes the epoxidation of α-pinene with molecular oxygen. The alkali and alkaline earth metal co-exchanged with Co(II) gives higher conversion than Co(II) alone. Effect of temperature and pressure was also studied to determine the optimum conditions for the reaction. The best results were obtained using NaCsCoY20 with 47% α-pinene conversion and 61% epoxide selectivity at 80 psi pressure and 373 K. Solvent was observed to play important role in epoxidation of α-pinene, and best results were observed in N, N-dimethylformamide as a solvent. Free radical mechanism has been proposed for the epoxidation of α-pinene.