Montmorillonite as a Heterogeneous Catalyst in the Efficient, Mild and One Pot Synthesis of Schiff Bases under Solvent-Free Conditions

Synthesis of N-Benzylideneaniline by Schiff base reaction using Kinnow peel powder as Green catalyst and comparative study of derivatives through ANOVA techniques

The cheap and easy availability of the Kinnow peel waste has reported various applications due to presence of multifunctional groups. Therefore, in present study we explored its application to synthesize N-Benzylideneaniline and its derivatives based on Schiff base reaction. Kinnow peel powder is characterized by FTIR, TEM, SEM, XRD, EDX, and TGA for functional groups, morphology, surface, elements and thermal stability. Benzaldehyde, aniline, and their derivatives such as 4-methyl benzaldehyde, 4-hydroxy benzaldehyde, 4-methoxy benzaldehyde, and 4-methoxy aniline have been used to compare the efficacy of the Schiff base reaction using analysis of variance (ANOVA) and it has been observed that combination of Aniline and benzaldehyde for Schiff base reaction provided 85% yield of relative product.

Generation of N-H Imines from α-Azidocarboxylic Acids through Ru-Catalyzed Decarboxylation

A new method for the synthesis of N-H imines from α-azidocarboxylic acids was developed, which proceeds through decarboxylative C-C bond cleavage catalyzed by a commercial diruthenium complex ([CpRu(CO)₂]₂) under visible light irradiation at room temperature within several minutes. The reactive products undergo condensation, which forms cyclic trimers (2,4,6-trialkylhexahydro-1,3,5-triazines) or linear N,N'-bis(arylmethylidene)arylmethanediamines in quantitative yields. Alternatively, the N-H imines can be trapped with benzylamine and 2-(aminomethyl)aniline, providing stable N-benylimines and tetrahydroquinazolines, respectively. Subsequent oxidation of tetrahydroquinazolines produced quinazolines.

Structural Studies of Multifunctional SrTiO3 Nanocatalyst Synthesized by Microwave and Oxalate Methods: Its Catalytic Application for Condensation, Hydrogenation, and Amination Reactions

The present study deals with the synthesis of SrTiO₃ (STO) nanocatalysts by conventional oxalate and microwave-assisted hydrothermal methods. Thorough characterization of the nanocatalysts synthesized has been done by using various techniques such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy, N₂ physisorption, transmission electron microscopy, total acidity by pyridine adsorption method, and acidic strength by n-butylamine potentiometric titration, respectively. Structural parameters were estimated by Rietveld refinement analysis from XRD data which confirms cubic structure of SrTiO₃. Traces of impurities such as TiO₂ and SrCO₃ were found in conventional catalysts, whereas these are absent in microwave catalyst. Brunauer-Emmett-Teller (BET) surface area of the microwave catalyst was enhanced 14-folds compared to conventional catalyst. Increase in Lewis acid sites and their strength were also observed in STO microwave catalyst. Catalytic performance of the catalysts was evaluated for various reactions, such as Knoevenagel condensation of benzaldehyde, catalytic transfer hydrogenation of nitrobenzene, and amination of benzaldehyde. Catalytic results reveal that microwave-synthesized catalyst showed 100% conversion and selectivity (>99% yield) for the chosen reactions than the conventional catalyst. Excellent catalytic activity of the STO microwave catalyst was due to high BET surface area, pore volume, and acidity of the catalyst, as compared to conventional catalyst. The present study marks the first-time application of perovskite-based SrTiO₃ as a potential multitasking cost-effective catalyst for the above reactions and synthesized using environment friendly microwave synthesis method.

CES as an Efficient Natural Catalyst for Synthesis of Schiff Bases under Solvent-Free Conditions: An Innovative Green Approach

A mild and efficient method has been reported for the preparation of Schiff base ligands through the condensation reaction of various aromatic aldehydes with substituted aromatic amines in the presence of CES (calcined eggshell) as a heterogeneous catalyst under solvent-free conditions. The advantages of this ecofriendly, economic method are simplicity of the reaction procedure, moderate to good product yields, and very short reaction times.