Schiff Base-Based Molybdenum Complexes as Green Catalyst in the Epoxidation Reaction: A Minireview

Epoxides are class of cyclic ether and have been extensively used in petrochemicals and pharmaceuticals industries as raw materials. Due to this reasons, development of the synthetic strategy of epoxides are getting enormous interest among the research chemists. In terms of "development of the synthetic strategy", the use of a catalyst, especially, Schiff base-based complex is of potential interest due to alternative easy routes and significant advances in metal-mediated pathways giving rise to diverse degree of substrate-reagent interactions. In addition, the synthetic strategy that follows the 12 principles of green chemistry, particularly (i) reduce the use of organic solvent, especially toxic solvents, and (ii) increasing the use of catalysts to obtain selective and quick processes in terms of atom economy, are of great attention now a days. The present review encompasses the Schiff base-based molybdenum complexes as green catalyst in the epoxidation reaction. Molybdenum complexes have grown interest owing to lower cost, environmental protection and commercialization as well as its abundance in different metalloenzymes. On the other hand, molybdenum complexes speed up the O-O bond break of tert-butylhydroperoxide (TBHP); as a result, it accelerates the oxygen transfer process from TBHP to the olefin. This review mainly focused on the catalytic activity of molybdenum-based Schiff base complexes for the epoxidation reaction in water/solvent free condition.

Effective adsorption of amoxicillin by using UIO-66@ Cr-MIL-101 nanohybrid: isotherm, kinetic, thermodynamic, and optimization by central composite design

In this research, the amoxicillin (AMX) removal was studied on a prepared nanosorbent from MOFs. The aim of this research work is to prepare nanohybrids based on metal-organic frameworks (MOFs) as an efficient nanosorbent for the absorption of amoxicillin drug. In this study, UIO-66 nanoparticles (UIO-66 NPs) were prepared from Zirconium (Zr) metal and 1,4-benzene dicarboxylic acid (BDC). Then UIO-66@Cr-MIL-101 nanohybrid was synthesized by hydrothermal method. Structural and physicochemical properties of nanohybrid UIO-66@Cr-MIL-101 were characterized by different analyses such as X-ray diffraction analysis (XRD), fourier transform infrared spectrometer (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), therapeutic goods administration (TGA), and Brunauer-Emmett-Teller (BET). The effect of four fundamental variables effective on adsorption was optimized by the central composite response surface methodology (CCRSM). This parameters including loading percentage of Cr-MIL-101 NPs (10-30%), initial concentration of AMX (20-140 mg L-1), contact time (20-60 min), and pH (20-10). The removal percentage (Re%) of AMX equal to 99.50% was obtained under the following conditions: The loading value of 20% Wt%, the initial concentration of AMX 80 mg L-1, contact time 20 min, and pH = 6. Also, the experimental data were investigated with famous kinetic models and isotherms, and it was observed that AMX removal by nanohybrid is correlated with the PSO kinetic model and Langmuir isotherm.

Catalytic epoxidation of olefins in liquid phase over manganese based magnetic nanoparticles

Epoxidation of olefins stands out as a crucial class of reactions and is of great interest in academic research and industry due to the production of various important fine chemicals and intermediates. Manganese complexes have the potential to catalyze the epoxidation of olefins with high efficiency. Magnetic nanocatalysts have attracted significant attention for immobilizing homogeneous transition metal complexes. Easy separation by external magnetic fields, nontoxicity, and a core shell structure are the main advantages of magnetic nanocatalysts over other heterogeneous catalysts. The method of functionalizing magnetic nanoparticles and of anchoring homogeneous metal complexes has significant effects on catalytic performance. Therefore, a critical review of recent research progress on manganese complexes' immobilization on magnetic nanoparticles for liquid phase olefin epoxidation is necessary. In this work, magnetic nanoparticles are categorized according to their preparation procedures and structures. The physical/chemical properties, catalytic performance for olefin epoxidation, reusability and plausible reaction mechanisms will be discussed, in an attempt to unravel the structure-function relationship and to guide the future study of MNPs' design for olefin epoxidations.

Polymer immobilized tantalum(v)–amino acid complexes as selective and recyclable heterogeneous catalysts for oxidation of olefins and sulfides with aqueous H2O2

Polymer supported peroxotantalate based heterogeneous catalysts served as highly efficient, selective and recyclable catalysts for alkene epoxidation and sulfide oxidation with green oxidant aqueous H₂O₂ under mild reaction conditions.