Synthesis and Characterization of Graphitic Carbon Nitride Supported Tris(Hydroxymethyl)Aminomethanem) G-C3N4/ THAM) as Novel Catalyst for the Synthesis of Poly Hydroquinoline and Pyranopyrazole Derivatives

Here, an impressive heterogeneous catalytic system, graphitic carbon nitride supported tris(hydroxymethyl)aminomethanem) g-C3N4/ THAM) is presented. The novel g-C3N4/ THAM nanocatalysts was characterized by analyzing methods such as FT-IR, EDX, XRD, TGA, and FESEM. Afterward, the performance of fabricated nanocatalyst g-C3N4/ THAM was suitably investigated in multicomponent reactions (MCRs) for the synthesis of 1,4-dihydropyridine and pyranopyrazole derivatives. By optimizing reported nanocatalyst, the corresponding reaction products were obtained with excellent efficiency and then the reversibility process was exanimated. The g-C3N4/ THAM nanocatalyst is environmentally friendly and was catalyzed the reactions in the presence of ethanol as a green solvent.

A versatile heterogeneous photocatalyst: nanoporous gold powder modified with a zinc(II) phthalocyanine derivative for singlet oxygen [4 + 2] cycloadditions

Nanoporous gold was functionalized with a photosensitizer, a zinc(II) phthalocyanine derivative. Such systems are active for the generation of reactive singlet oxygen which can be used for photocatalytic oxidation reactions. This study aims to demonstrate the versatility of such an approach, in terms of substrates and the employed solvent, only possible for a truly heterogeneous catalytic system. The activity of the hybrid system was studied for [4 + 2] cycloadditions of three different types of dienes and a total of eight substrates in two organic solvents and once in water. The highest activity was measured for 1,3-diphenylisobenzofuran, which is also highest in terms of sensitivity for the reaction with 1O2. Trends in conversion could be anticipated based on reported values for the rate constant for the reaction of 1O2. In almost all cases, an amplification of the conversion by immobilization of the sensitizer onto nanoporous gold was observed. The limiting case was ergosterol, which was the largest of all substrates with a van-der-Waals radius of about 2.1 nm. Additional factors such as the limited lifetime of 1O2 in different solvents as well as the hampered diffusion of the substrates were identified. Graphic abstract

A new and efficient methodology for olefin epoxidation catalyzed by supported cobalt nanoparticles

A new heterogeneous catalytic system consisting of cobalt nanoparticles (CoNPs) supported on MgO and tert-butyl hydroperoxide (TBHP) as oxidant is presented. This CoNPs@MgO/t-BuOOH catalytic combination allowed the epoxidation of a variety of olefins with good to excellent yield and high selectivity. The catalyst preparation is simple and straightforward from commercially available starting materials and it could be recovered and reused maintaining its unaltered high activity.

Direct propylene epoxidation with oxygen enabled by photo-electro-heterogeneous catalytic system

Propylene oxide (PO) is a crucial feedstock in the plastic industry. The direct epoxidation of propylene using O2 is considered to be the most promising means of producing PO, but it remains challenging. Here, we report on an integrated photo-electro-heterogeneous catalytic system for propylene epoxidation with O2. Bismuth vanadate (or TiO2) photocatalyst and Co-based electrocatalyst produce H2O2 and titanium silicalite-1 heterogeneous catalyst epoxidises propylene to PO with the in situ generated H2O2. This system enables PO production with O2 as the sole oxidising agent under light irradiation without using H2, a sacrificial agent, or external bias. It stably produces PO for 24 h with high selectivity (≥ 98%) under ambient conditions. These results demonstrate the potential of this new catalytic system to produce chemical compounds in an environmentally benign manner.

Highly porous copper-supported magnetic nanocatalysts: made of volcanic pumice textured by cellulose and applied for the reduction of nitrobenzene derivatives

Herein, a novel designed heterogeneous catalytic system constructed of volcanic pumice magnetic particles (VPMPs), cellulose (CLS) as a natural polymeric matrix, and copper nanoparticles (Cu NPs) is presented.

Hydromagnesite sheets impregnated with cobalt–ferrite magnetic nanoparticles as heterogeneous catalytic system for the synthesis of imidazo[1,2-a]pyridine scaffolds

Sustainable synthesis of imidazo[1,2-a]pyridine scaffolds assisted by hydromagnesite sheets impregnated with cobalt–ferrite (CoFe2O4-HMS) magnetic nanoparticles (MNPs).