Graphene oxide supported ionic liquid/Fe complex: a robust and highly stable nanocatalyst

A Pd-containing ionic liquid modified magnetic graphene oxide nanocomposite (Fe3O4/GO-IL-Pd) as a powerful catalyst for the reduction of nitrobenzenes

A novel palladium-containing ionic liquid-modified magnetic graphene oxide nanocomposite (Fe3O4/GO-IL-Pd) is synthesized and its catalytic performance is studied in the reduction of nitrobenzenes. The Fe3O4/GO-IL-Pd nanocomposite was characterized by using FT-IR, PXRD, SEM, EDS, VSM, and TG analyses. These analyses showed good magnetic properties and high stability of the designed composite. Different derivatives of nitrobenzenes were applied as substrates, giving corresponding anilines in high to excellent yields (89-96%) at short reaction times (10-15 minutes). Also, the stability, reproducibility, and reusability of the Fe3O4/GO-IL-Pd nanocomposite were investigated under applied conditions. A leaching experiment was also performed to study the nature of the Fe3O4/GO-IL-Pd catalyst under the conditions used.

Functionalized graphene oxide by 4-amino-3-hydroxy-1-naphthalenesulfonic acid as a heterogeneous nanocatalyst for the one-pot synthesis of tetraketone and tetrahydrobenzo[b]pyran derivatives under green conditions

4-Amino-3-hydroxy-1-naphthalenesulfonic acid-functionalized graphene oxide (GO-ANSA) was prepared and characterized using different spectroscopic, microscopic and analytical methods including energy-dispersive X-ray spectroscopy (EDS), EDS elemental mapping, Fourier-transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and thermogravimetry/differential thermogravimetry analysis (TGA/DTA). The obtained nanomaterial was used as a novel, highly efficient, and reusable solid acid carbocatalyst for the one-pot three-component synthesis of tetraketone, as well as tetrahydrobenzo[b]pyran derivatives via tandem Knoevenagel-Michael reactions under green conditions. All of the derivatives were prepared in EtOH, as a green solvent, under reflux conditions in high to excellent yields and very short reaction times. The nanocatalyst was recovered and reused at least five times without significant reduction in its activity. In addition, the absence of toxic transition metals, high to excellent yields, mild reaction conditions, simple procedure for the separation and purification of products, stability, and recycling of the catalyst are the most important advantages of this green procedure.

Ionic liquid containing high-density polyethylene supported tungstate: a novel, efficient, and highly recoverable catalyst

Synthesis and catalytic application of polymeric-based nanocomposites are important subjects among researchers due to their high lipophilicity as well as high chemical and mechanical stability. In the present work, a novel nanocomposite material involving ionic liquid and high-density polyethylene supported tungstate (PE/IL-WO4 =) is synthesized, characterized and its catalytic application is investigated. The coacervation method was used to incorporate 1-methyl-3-octylimidazolium bromide ([MOIm] [Br]) ionic liquid in high-density polyethylene, resulting in a PE/IL composite. Subsequently, tungstate was anchored on PE/IL to give PE/IL-WO4 = catalyst. The PXRD, FT-IR, EDX, TGA, and SEM analyses were used to characterize the PE/IL-WO4 = composite. This material demonstrated high catalytic efficiency in the synthesis of bioactive tetrahydrobenzo[a]xanthen-11-ones under green conditions. The recoverability and leching tests were performed to investigate the stability and durability of the designed PE/IL-WO4 = catalyst under applied conditions.

Magnetic silica/graphene oxide nanocomposite supported ionic liquid-manganese complex as a powerful catalyst for the synthesis of tetrahydrobenzopyrans

A novel magnetic silica/graphene oxide nanocomposite supported ionic liquid/manganese complex (Fe3O4@SiO2-NH2/GO/IL-Mn) is prepared, characterized and its catalytic application is investigated. The Fe3O4@SiO2-NH2/GO/IL-Mn catalyst was synthesized via chemical immobilization of graphene oxide on Fe3O4@SiO2 nanoparticles followed by modification with ionic liquid/Mn complex. This nanocomposite was characterized by using SEM, TGA, FT-IR, PXRD, EDX, TEM, nitrogen adsorption-desorption, and VSM analyses. The catalytic application of Fe3O4@SiO2-NH2/GO/IL-Mn was studied in the synthesis of tetrahydrobenzo[b]pyrans (THBPs) in water solvent at RT. This nanocatalyst was successfully recovered and reused at least eight times without a significant decrease in its activity.