Curbed of molybdenum oxido-diperoxido complex on ionic liquid body of mesoporous Bipy-PMO-IL as a promising catalyst for selective sulfide oxidation

Abstract

In this work, we introduce a novel bipyridinium ionic liquid bridged periodic mesoporous organosilicas (Bipy-PMOs-IL) which is used as the support to immobilize oxygen-rich Molybdenum (VI)-based oxido-peroxido complex (MoO(O2)2@Bipy-PMO-IL). Several techniques such as Small-angle X-ray scattering (SAXS), low angle XRD, FE-SEM (field emission scanning electron microscope), TEM (transmission electron microscope), N2 adsorption-desorption analyses (BET), atomic absorption spectroscopy (AAS), Fourier-transform infrared spectroscopy (FT-IR) and Energy Dispersive X-Ray (EDS or EDX) were used to characterize this nanomaterial. Also, the catalytic activities of the MoO(O2)2@Bipy-PMO-IL as a hybrid catalyst is tested in the selective oxidation of sulfides in water by using H2O2 (30%) as an eco-friendly and green co-oxidant. The as-prepared novel catalyst shows high to excellent performance under optimum reaction conditions at ambient room temperature. The obtained results in this work show several outstanding advantages, such as green conditions, high product yields, easy work-up, easy preparation and acceptable reusability of the catalyst for at least 5 runs. To study the IL effect in immobilization of Mo-complex, in a comparison study, the MoO(O2)2@Bipy-PMO-IL materials and MoO(O2)2@SBA-15 (with simple SiO2 body, no IL) body were employed for sulfide oxidation. After the treatment, the Mo@Bipy-PMO-IL with IL body in channels was reused for subsequent experiments (5 runs), but in Mo@SBA-15 after second run the yield was decreased dramatically.