One-pot Synthesis of 1-Amidoalkyl-2-naphthols Catalyzed by Polyphosphoric Acid Supported on Silica-coated NiFe2O4 Nanoparticles

Photofixation of N2 to ammonia utilizing Ni@TPP-HPA nanocomposite under visible-light illumination

The production of ammonia as an important raw material in the chemical, agricultural, and food industries has been always a significant concern. However, conventional ammonia production methods require high energy consumption and costs. The photocatalytic rotes use green light sources and cost-effective photocatalysts to obtain ammonia from water under aerobic conditions and preventing production of greenhouse gases in the environment. To produce an effective heterogeneous catalyst, a new tetraphenylporphyrin-heteropolyacid (TPP-HPA) nanohybrid material is synthesized and loaded onto Ni nanoparticles in this work. Then, FE-SEM, EDS, XRD, and FT-IR analyses were applied to characterize the prepared nanohybrid material Ni@TPP-HPA. After that, the new inorganic-organic nanohybrid photocatalyst was introduced as an effective, environmental friendly, and recyclable mediator for N2 photofixation. The results showed that Ni@TPP-HPA is a good photocatalyst for the N2 fixation reaction and can be easily recycled without losing its activity for at least five runs. The Ni@TPP-HPA nanocomposite demonstrated the maximum ammonia generation by 2760 μmol L-1 g-1 under mild conditions when using methanol as a hole scavenger. Additionally, effects of solvent type, temperature, reaction time, irradiation source, solution pH, and other electron scavengers on the rate of NH4+ production were investigated and discussed.

SnO2 nanoparticles: A recyclable and heterogeneous catalyst for Pechmann condensation of coumarins and Knoevenagel condensation–Michael addition of biscoumarins

Recyclable SnO₂ nanoparticles catalyze the Pechmann condensation between phenolic alcohols and β-ketoesters at room temperature in ethanol leading to coumarins. Also, in another study the synthesis of biscoumarins catalyzed by SnO₂ nanoparticles in the reaction between 4-hydroxycoumarin and aldehydes under same condition reactions. The corresponding coumarins and biscoumarins were produced efficiently with facility and excellent yields (93-98%). These approaches display the advantages of benign reaction conditions, non-chromatographic purification procedure, appropriate functional group tolerance and valuable process.

Synthesis, characterization and first application of covalently immobilized nickel-porphyrin on graphene oxide for Suzuki cross-coupling reaction

In this study, nickel(ii)-coordinated 5,10,15,20-tetrakis(aminophenyl)porphyrin (NiTAPP) as a macrocyclic complex was covalently grafted to the edge of graphene oxide (GO) and applied as nanocatalyst in Suzuki cross-coupling reaction.

A magnetic metal–organic framework as a highly active heterogeneous catalyst for one-pot synthesis of 2-substituted alkyl and aryl(indolyl)kojic acid derivatives

A novel magnetic metal–organic framework, NiFe₂O₄@MOF-5, was prepared and demonstrated to be a highly efficient catalyst for the one-pot three-component reaction of aldehyde, indole, and kojic acid.

Ultrasound promoted facile one pot synthesis of highly substituted pyran derivatives catalyzed by silica-coated magnetic NiFe2O4nanoparticle-supported H14[NaP5W30O110] under mild conditions

Application of ultrasonic method as a green source of energy to reduce the reaction times compared to conventional processes. NiFe₂O₄@SiO₂–H₁₄[NaP₅W₃₀O₁₁₀] was used as magnetically separable catalyst for synthesis of pyrans with minimum work up.

Green synthesis of tetrahydrobenzo[b]pyrans, pyrano[2,3-c]pyrazoles and spiro[indoline-3,4′-pyrano[2,3-c]pyrazoles catalyzed by nano-structured diphosphate in water

Preparation of nanostructured diphosphate Na₂CaP₂O₇. Avoiding of any acid catalysts. The prepared catalyst is reusable and eco-friendly. The method is easy and contains simple experimental procedure.