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Through this work, a family of sulfonamide functionalized mesoporous materials as sustainable heterogeneous catalysts has been successfully synthesized by employing sulfaguanidine, sulfathiazole, and sulfadiazine. The samples were fully characterized using a multitechnique approach. Such materials have proved to be highly versatile and catalytically active in both the advances in the hydrogenation of Levulinic acid through heterogeneous catalytic transfer hydrogenation (CTH) and oxidation reactions with a strong emphasis on discussing morphology and structure of versatile catalysts, plausible mechanism, and performance of the catalysts for biomass valorization of renewable feedstock. In particular, the prepared catalytic systems were tested in levulinic acid transformation into γ-Valerolactone, achieving a maximum conversion of 99% and a selectivity of 90% for the sulfaguanidine modified sample. The three nanocatalysts displayed good stability over four reuse cycles, and by considering the results of a hot filtration test, it is confirmed that the nature of the catalysis is heterogeneous as acid-base pairs and functionalized groups on catalytic activation of C–H and C O bonds for transfer hydrogenation of levulinic acid. Moreover, such samples also showed remarkable results in the oxidation of benzyl alcohol towards benzaldehyde, with conversion and selectivity values of 95% and 97%, respectively. The obtained catalytic results are highly promising for biomass upgrading processes, looking forward to a more sustainable future.

Grafting 6-aminopenicillanic acid (6-APA) onto superparamagnetic γ-Fe2O3@SiO2 nanocomposites led to the production of 6-APA/γ-Fe2O3@SiO2 as a novel heterogeneous nanocatalyst. Protonation and deprotonation of 6-APA/γ-Fe2O3@SiO2 nanocomposites were investigated using quantum mechanical calculations. The behaviour of bifunctionality on this catalyst was examined and the results showed that it acts as an acid–base bifunctional system, and the reaction proceeds very well under mild and ambient conditions. The deprotonation of the COOH group is easier than the NH and NH2 groups with respect to the energy data and the results of the molecular electrostatic potential (MEP) analyses. In the presence of the nanocomposite, the protonation of the NH2 group is more favourable than the NH group. It was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), vibrating sample magnetometery (VSM), thermo-gravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FT-IR). This reaction is not only kinetically stable but is also a spontaneous reaction and thermodynamically favored. The superparamagnetic nanocomposite was used in the preparation of 1,4-dihydropyrano[2,3-c]pyrazole derivatives under a one-pot multicomponent reaction. The nanocomposite was recyclable for at least 10 cycles without any loss in the activity.

A mechanochemical protocol was applied to the synthesis of a magnetic material based on iron oxide nanoparticles and Al-SBA-15. Full characterization of the prepared Fe2O3/Al-SBA-15 evidenced the effective functionalization of the aluminosilicate surface. Particularly, TEM analysis revealed that the mechanochemical protocol did not considerable affect the hexagonal ordered structure of Al-SBA-15. DRIFT experiments of Fe2O3/Al-SBA-15 showed interesting acidic properties, which can be further associated to a good catalytic performance. The catalytic behavior of the prepared material was tested in the oxidation of vanillyl alcohol to vanillin, displaying an excellent activity and selectivity. The material resulted to be highly stable in the aforementioned reaction, without considerable decrease of conversion after 10 reuse cycles.

The present work describes two novel magnetic composite catalysts, synthesized by functionalizing the silica/iron oxide composite surface with sulfaguanidine and sulfadiazine. The sulfaguanidine functionalized catalyst was found to be very efficient for multicomponent coupling reactions of phenylacetylene with various aldehydes and amines. The sulfadiazine functionalized catalyst was successfully applied in the synthesis of various 1,8-dioxo-octahydroxanthenes in water. Both the sulfaguanidine and sulfadiazine functionalized catalysts were very active and selective in the alkylation of toluene with benzyl chloride.

The authors regret the missing Scheme 1 in the text (page 3, before physicochemical characterisation) which was corrected at proof stage but absent in the final manuscript. The authors would like to apologise for any inconvenience caused.

Magnetic core-shell Fe2O3@polymer-Pd/Cu nanocomposites (NCs) were developed as efficient and sustainable nanocatalysts for cross-coupling reactions. The designed NCs consisted of three components: i) a magnetic core (Fe2O3 nanoparticle), which allowed the recovery and reuse of the NCs, enhancing thus their attractiveness as green catalysts; ii) a catechol-based polymer coating, chosen because of its strong chelating ability towards metal ions, and its potential to be obtained from biomass (lignin depolymerization); and iii) catalytically active metal nanoparticles (Pd and Cu NPs) immobilized via in situ formation onto the polymeric shell. As-prepared Pd-based NCs successfully catalyzed Suzuki-Miyaura cross-coupling reactions, achieving yields between 87% and 97% in only 20–40 min depending on the aryl halides and boronic acid derivatives. Similarly, Cu-based NCs exhibited a quite good catalytic efficiency (> 80%) in the synthesis of propargylamines via A3 coupling reaction of phenylacetylene with various aldehydes and amines. Importantly, these NCs presented a good reusability, without significant decrease in efficiency after several cycles. However, the major advantage of the designed NCs is the lower Pd or Cu content (1.5 wt% and 2.6 wt%, respectively) as compared to most of the reported similar catalysts (between 3 – 6 wt% for Pd and > 5 wt% for Cu), which is a key challenge in view of developing cost-effective and environment-friendly catalysts while maintaining a high efficiency.

Catalyst design and surface modifications of magnetic nanoparticles have become attractive strategies in order to optimize catalyzed organic reactions for industrial applications. In this work, silica-coated magnetic nanoparticles with a core-shell type structure were prepared. The obtained material was successfully functionalized with sulfathiazole groups, which can enhance its catalytic features. The material was fully characterized, using a multi-technique approach. The catalytic performance of the as-synthesized material was evaluated in 1) the oxidation of benzyl alcohol to benzaldehyde and 2) the microwave-assisted alkylation of toluene with benzyl chloride. Remarkable conversion and selectivity were obtained for both reactions and a clear improvement of the catalytic properties was observed in comparison with unmodified &gamma, Fe2O3/SiO2 and &gamma, Fe2O3. Noticeably, the catalyst displayed outstanding magnetic characteristics which facilitated its recovery and reusability.