Waste-to-wealth: biowaste valorization into valuable bio(nano)materials

The waste-to-wealth concept aims to promote a future sustainable lifestyle where waste valorization is seen not only for its intrinsic benefits to the environment but also to develop new technologies, livelihoods and jobs. Based on the concept of waste valorization and circular economy, this review aims to provide an overview of present trends and future potential in the conversion of residues from different food sectors into valuable bio(nano)material

Synthesis of a magnetic polystyrene-supported Cu(II)-containing heterocyclic complex as a magnetically separable and reusable catalyst for the preparation of N-sulfonyl-N-aryl tetrazoles

In this work, a cost-effective, environmentally friendly, and convenient method for synthesizing a novel heterogeneous catalyst via modification of polystyrene using tetrazole-copper magnetic complex [Ps@Tet-Cu(II)@Fe3O4] has been successfully developed. The synthesized complex was analyzed using TEM (transmission electron microscopy), HRTEM (high resolution-transmission electron microscopy), STEM (scanning transmission electron microscopy), FFT (Fast Fourier transform), XRD (X-ray diffraction), FT-IR (Fourier transform-infrared spectroscopy), TG/DTG (Thermogravimetry and differential thermogravimetry), ICP-OES (Inductively coupled plasma-optical emission spectrometry), Vibrating sample magnetometer (VSM), EDS (energy dispersive X-ray spectroscopy), and elemental mapping. N-Sulfonyl-N-aryl tetrazoles were synthesized in high yields from N-sulfonyl-N-aryl cyanamides and sodium azide using Ps@Tet-Cu(II)@Fe3O4 nanocatalyst. The Ps@Tet-Cu(II)@Fe3O4 complex can be recycled and reused easily multiple times using an external magnet without significant loss of catalytic activity

Advances in Magnetic Nanoparticles-Supported Palladium Complexes for Coupling Reactions

Carbon‒carbon (C‒C) and carbon‒heteroatom (C‒X) bonds that form via transition-metal-catalyzed processes have been extensively used in the organic synthesis and preparation of natural products and important compounds such as heterocycles, biologically active molecules, and dendrimers. Among the most significant catalysts, magnetic nanoparticles-supported palladium complexes are very effective, versatile, and heterogeneous catalysts for a wide range of C‒C and C‒X coupling reactions due to their reusability, thermal stability, and excellent catalytic performance. In this review, recent advances to develop magnetic nanoparticles supported palladium complexes, including their preparation, characterization, catalytic application, and reusability in the formation of both C‒C and C‒X bonds, by authors such as Sonogashira, Heck, Suzuki‒Miyaura, and Stille, and a few examples concerning N-arylation, S-arylation, and Csp2-P coupling reactions are discussed

Facile fabrication of magnetically separable palladium nanoparticles supported on modified kaolin as a highly active heterogeneous catalyst for Suzuki coupling reactions

Baran, Talat ( Aksaray, Yazar )In this study, Fe3O4 loaded Schiff base modified kaolin was prepared as a new support and palladium nanoparticles were anchored on it without any additional reducing agent (Pd NPs@Kao/Fe3O4/Pyr). Characterization studies demonstrated that Pd NPs@Kao/Fe3O4/Pyr was successfully designed and the size of particles was about 25 nm. Pd NPs@Kao/Fe3O4/Pyr was then utilized as catalyst in the preparation of biaryl compounds via Suzuki cross coupling reactions. Catalytic tests showed that Pd NPs@Kao/Fe3O4/Pyr acted as a highly active heterogeneous nanocatalyst in the coupling reaction of aryl iodides, bromides and chlorides containing different functional groups. Moreover, it was found that Pd NPs@Kao/Fe3O4/Pyr was successfully used in consecutive recycling tests and gave an 89% yield even after ten runs. In addition to the high catalytic behavior and reusability, Pd NPs@Kao/Fe3O4/Pyr have some advantages such as i) capability of application for various halides containing different functional groups, ii) ease of purification of final product and iii) simple work-up

Pd/CoFe2O4/chitosan: A highly effective and easily recoverable hybrid nanocatalyst for synthesis of benzonitriles and reduction of 2-nitroaniline

Baran, Talat ( Aksaray, Yazar )In this study, a novel catalyst system with high activity and easy recoverability was successfully prepared through the deposition of Pd nanoparticles (NPs) onto designed sustainable hybrid beads containing magnetic cobalt ferrite and chitosan (Pd/CoFe2O4/chitosan). The catalytic potential of Pd/CoFe2O4/chitosan hybrid nanocatalyst was then assessed in i) preparation of benzonitriles via aryl halides cyanation and ii) reduction of 2nitroaniline (2-NA). Various aryl iodides and bromides were successfully cyanated by Pd/CoFe2O4/chitosan hybrid nanocatalyst with excellent reaction yields within 3 h. In addition to the production of benzonitriles, the hybrid nanocatalyst showed excellent activity by reducing 2-NA in 65 s. It was proved that the Pd/CoFe2O4/chitosan hybrid nanocatalyst outperformed many catalysts used in the cyanation of aryl halides and catalytic reduction of 2-NA previously reported in the literature. Moreover, it was found that the designed Pd/CoFe2O4/chitosan hybrid nanocatalyst was easily and effectively separated from the reaction mixture using an external magnet and reused several times in catalytic reactions without considerable loss of catalytic activity

Green synthesis of palladium nanocatalyst derived from the β-cyclodextrin used as effective heterogeneous catalyst for cyanation of aryl halides

Baran, Talat ( Aksaray, Yazar )In this study, preparation of highly stable palladium nanoparticles (Pd NPs) on Schiff base modified β-cyclodextrin (β-CD-Sch) in the absence of reducing agents has been successfully carried out. Pd NPs@β-CD-Sch has then been applied as nanocatalyst in the synthesis of benzonitriles via cyanation reaction using K4Fe(CN)6, which is a low cost, commercially available and non-toxic cyanide source. A series of benzonitriles containing different substrates were successfully fabricated with 77–98% yields using Pd NPs@β-CD-Sch. Moreover, Pd NPs@β-CD-Sch catalyst was quantitatively recovered and reutilized several times, showing good reaction yields. This work revealed that i) prepared β-CD-Sch is an effective stabilizer for the fabrication of Pd NPs and ii) Pd NPs@β-CD-Sch catalyst play an important role in the fabrication of benzonitriles

Facile synthesis of palladium nanoparticles immobilized on magnetic biodegradable microcapsules used as effective and recyclable catalyst in Suzuki-Miyaura reaction and p-nitrophenol reduction

This study reports (i) preparation and characterization of palladium nanoparticles (Pd NPs) stabilized on magnetically separable chitosan/agar microcapsules (Pd NPs@Fe3O4/CS-AG microcapsules) and (ii) investigation of catalytic behaviors of the prepared nanoparticles in Suzuki-Miyaura C-C cross-coupling reactions and reduction of p-nitrophenol (p-NP). Fourier transforms infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), elemental mapping, inductively coupled plasma-optical emission spectrometry (ICP-OES) and thermogravimetry/derivative thermogravimetry (TG/DTG) techniques were used for analyzing the Pd NPs@Fe3O4/CS-AG microcapsules. Characterization studies showed that Pd NPs@Fe3O4/CS-AG microcapsules were successfully synthesized and the size of the particles was in the range of 28–39 nm. Pd NPs@Fe3O4/CS-AG microcapsules displayed highly effective catalytic performance in the conversion of various aryl halides into the corresponding biaryl derivatives by Suzuki-Miyaura reaction under solvent-free conditions in 5 min. Pd NPs@Fe3O4/CS-AG microcapsules were also successfully employed in p-NP reduction to p-aminophenol (p-AP) in water at room temperature in 180 s. Moreover, reproducibility studies showed that Pd NPs@Fe3O4/CS-AG microcapsules were highly efficient and could be used many times in both catalytic reactions due to their magnetically separable nature. According to the results of this work, Pd NPs@Fe3O4/CS-AG microcapsules are highly efficient, economical, practical and environmentally superb catalysts for Suzuki-Miyaura reaction and p-NP reduction. © 2019Aksaray Üniversitesi Qom Islamic Azad UniversityWe gratefully acknowledge the Aksaray University, Iranian Nano Council and the University of Qom for the support of this work

Cyanation of aryl halides and Suzuki-Miyaura coupling reaction using palladium nanoparticles anchored on developed biodegradable microbeads

Baran, Talat ( Aksaray, Yazar )This work reports i) green synthesis of palladium nanoparticles (Pd NPs) on the developed biodegradable microbeads as stabilizers, featuring chitosan, agarose and beta-cyclodextrin, ii) investigation of the catalytic role of the Pd NPs prepared in the Suzuki-Miyaura and iii) cyanation reactions. Pd NPs@microcapsules (CAP) convert a series of aryl halides to biphenyl compounds with yields ranging from 79 to 98%. Pd NPs@CAP is highly active in the cyanation of different aryl bromides and iodides using K4[Fe(CN)6] and is used to prepare benzonitriles with a yield of up to 97%. More importantly, Pd NPs@CAP is easily recovered from the reaction mixture and successfully reused seven consecutive times in the Suzuki-Miyaura and cyanation reactions. This significant features of Pd NPs@CAP are i) ease of purification of desired biaryls and benzonitriles and ii) production of no by-products in both catalytic reaction

Facile preparation of nanostructured Pd-Sch-delta-FeOOH particles: A highly effective and easily retrievable catalyst for aryl halide cyanation and p-nitrophenol reduction

Iron based compounds are good candidates as supports to immobilize different transition metals due to their eco-friendly nature, capability of facilitating chemical modifications, inexpensiveness, high stability and easy recoverability. In this study, palladium nanoparticles (Pd NPs) were successfully stabilized on designed Schiff base modified delta-FeOOH particles as a highly effective and readily recoverable heterogeneous catalyst (Pd-Sch-delta-FeOOH nanocatalyst). The catalyst was fabricated via a facile multi-step approach without utilizing any additional reducing agents. The Pd-Sch-delta-FeOOH was characterized by Fourier transforms infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET). Characterization studies confirmed that the prepared small sized Pd NPs were spherically shaped and well dispersed on the surface of Schiff base modified delta-FeOOH. The catalytic efficiency of Pd-Sch-delta-FeOOH nanocatalyst was then tested in the preparation of benzonitriles through cyanation of aryl halides using K-4[Fe(CN)(6)] has been utilized as a cyanation agent and also reduction of p-nitrophenol (p-NP) using NaBH4 as the reducing agent. Benzonitriles were characterized using GC-MS. Catalytic studies showed that benzonitriles were obtained in good reaction yields in the presence of heterogeneous Pd-Sch-delta-FeOOH nanocatalyst (87-98%). It was found that Pd-Sch-delta-FeOOH was also a useful nanocatalyst for p-NP reduction at ambient temperature in eco-friendly media within 2 min. The reduction rate for p-NP with Pd-Sch-delta-FeOOH was measured via UV-Vis spectroscopy from 250 nm to 550 nm. Furthermore, Pd-Sch-delta-FeOOH nanocatalyst was able to remain active for six successive runs due to its recyclable/reusable nature