•Ni2+-O-CMCS-CCs was synthesized for lysozyme purification.•Adsorption of 244.6 and 15.3 mg/g was reached with Ni2+ and without Ni2+ particles.•More than 95% of adsorbed lysozyme was desorbed in ...about 20 min.•The same column was showed 35 adsorption-desorption cycles.
We synthesized Ni2+-attached O-Carboxymethyl chitosan Schiff base complexes embedded composite cryogels (Ni2+-O-CMCS-CCs) by means of polymerization of gel-forming precursors at subzero temperatures. Prepared affinity cryogel showed excellent adsorption performance for lysozyme selected as model protein to test adsorption parameters, demonstrating an adsorption capacity of 244.6 mg/g (15.3 mg/g for Ni2+ minus O-CMCS-CCs), with fast adsorption equilibrium within 30 min and good reversibility. The performance of Ni2+-O-CMCS-CCs for lysozyme was also evaluated by SDS-PAGE, and a purification efficiency of 86.9% with 89.5% purification yield was determined. The swelling test, FT-IR, and SEM analysis were carried out for the characterization of Ni2+-O-CMCS-CCs. At the end of 35 adsorption-desorption cycles, there was no significant change in the adsorption capacity.
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•Magnetically separable sporopollenin-based Pd(II) catalyst observed superior reusability.•Outstanding TON and TOF value was reached; 99.000, 1.237.500.•The catalyst showed an ...excellent performance in Suzuki coupling reactions.
In any catalysis system, regeneration of the used catalyst is of great importance to reduce the cost of industrial applications. However, recovery of the used catalyst from the reaction medium is a difficult task and this can hinder regeneration process. Magnetic separation has emerged as an effective tool to overcome the recovery problem. Hence, in this study a magnetically recoverable sporopollenin-based Pd catalyst has been designed and used in synthesis of biaryl compounds via Suzuki coupling reaction. The thermally stable catalyst exhibited excellent catalytic behaviour without giving any by-products. It is noteworthy that despite their low product yield of aryl chlorides in coupling reactions, remarkable product yields which are comparable to those of aryl bromides and iodides were recorded for aryl chlorides. With very low catalyst loading (1×10−3mol%), the catalyst gave TOFs values exceeding one million; i.e., 1.237.500 in very short reaction time. Due to its magnetically separable nature, the catalyst could be recovered from the reaction media easily by increasing the reusability of the catalyst. Even in tenth run biphenyl yield dropped from 99 to 93%.
In this study, a novel highly efficient, recoverable, sustainable, and thermally stable Schiff base polymer-Pd(II) catalyst was designed for Suzuki coupling reactions in synthesis of biaryl compounds ...for the first time. Firstly, a novel Schiff base polymer containing phenol, Poly(4-((pyridine-2ylimino)methyl)benzene-1,3-diol) (P (4-PMB)), which was used as a support material in catalyst design, was synthesized in aqueous alkaline medium via oxidative polycondensation of 4-((pyridine-2-ylimino)methyl)benzene-1,3-diol (4-PMB) with NaOCl oxidant. The effects of oxidant concentration, polymerization temperature, and time on yield and molecular weight of the polymer were investigated. The structures of the synthesized compounds were illuminated by UV–Vis, FTIR, 1HNMR, XRD, TG/DTG, and SEM/EDAX methods. Then, Pd(II) complex of P (4-PMB) was produced, and its catalytic performance was tested in the synthesis of various biaryl compounds by Suzuki reactions using microwave irradiation technique which is a highly effective, fast, solvent-free and green method. The designed Pd(II) catalyst exhibited superior catalytic effect against syntheses of various biaryl compounds with high conversion yields (99%) and very low catalyst loading (0.01 mol%) for 5 min. Recyclability and reproducibility tests showed that the catalyst could be reused for seven successive runs without any great loss of its catalytic performance (84%).
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•A novel highly efficient and thermally stable Schiff base polymer-Pd(II) catalyst was designed.•The catalyst was used for Suzuki coupling reactions in synthesis of biaryls.•Suzuki reactions were performed using solventless microwave irradiation method.•The catalyst exhibited superior catalytic effect against various biaryls for 5 min.•The catalyst could be reused for seven successive runs (84%).
In this paper we described the fabrication, characterization and application of a new biopolymer (chitosan)-based pincer-type Pd(II) catalyst in Suzuki cross coupling reactions using a non-toxic, ...cheap, eco-friendly and practical method. The catalytic activity tests showed remarkable product yields as well as TON (19800) and TOF (330000) values with a small catalyst loading. In addition, the catalyst indicated good recyclability in the Suzuki C-C reaction. This biopolymer supported catalyst can be used with various catalyst systems due to its unique properties, such as being inert, green in nature, low cost and chemically durable.
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•A new pincer-type Pd(II) catalyst was obtained using chitosan biopolymer.•The catalyst gave outstanding TONs of up to 19800 and TOFs of up to 330000.•This chitosan-based pincer-type Pd(II) catalyst showed a better recycle performance.
Removal of organic pollutants such as aromatic nitro compounds and dyes from wastewaters is very significant for environment, and the best strategy is their reduction/degradation in the presence of a ...metal catalyst. In this study, a new palladium nanocatalyst (GA-Sch-Pd) was prepared derived from modified gum arabic and characterized by FT-IR, TGA, FE-SEM, EDS, TEM, and XRD analyses. Then, the catalytic potential of GA-Sch-Pd nanocatalyst was tested in the catalytic reductions of different organic pollutants such as o-nitroaniline (o-NA), p-nitrophenol (p-NP), p-nitro-o-phenylenediamine (p-NPDA), p-nitroaniline (p-NA), congo red (CR), methylene blue (MB), and methyl orange (MO) by using NaBH4 in water. These tests showed GA-Sch-Pd nanocatalyst had high activity against reduction of nitroarenes and organic dyes at very short reaction durations. Moreover, GA-Sch-Pd nanocatalyst was easily separated and reused for several times. This study shows that GA-Sch-Pd nanocatalyst has a high potential for remediation of environmental pollutants in wastewaters.
•GA-Sch-Pd was fabricated as a heterogeneous nanocatalyst.•GA-Sch-Pd nanocatalyst was characterized by FT-IR, TGA, XRD, SEM, EDS, and TEM analyses.•GA-Sch-Pd was used as a nanocatalyst for the reduction of nitroarenes and organic dyes in water.•GA-Sch-Pd nanocatalyst displayed good stability and reusability.
This study reports the synthesis of two new water soluble O-carboxymethyl chitosan Schiff bases (OCMCS-5 and OCMCS-6a) and their Cu(II) and Pd(II) complexes. Characterizations of these complexes were ...carried out with FTIR, elemental analysis, 13C CPMAS, UV–vis, magnetic moment and molar conductivity techniques. The degrees of substitution (DS) for OCMCS-5a and OCMCS-6a were determined to be 0.48 and 0.44 in elemental analysis. The solubility test revealed that OCMCS-5a and OCMCS-6a dissolved thoroughly in water. The surface morphologies of chitosan (CS), OCMCS-5a, OCMCS-6a and their complexes were studied with SEM-EDAX. Thermal stability of the synthesized compounds was evaluated by TG/DTG and their crystallinity values were investigated with powder X-ray diffraction. Cu(II) and Pd(II) contents of the complexes were estimated with ICP-OES. The characterization studies demonstrated that the thermal stability and crystallinity values of the OCMCS-5a and OCMCS-6a were lower than those of CS.
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•Synthesis and characterization O-carboxymethyl chitosan Schiff bases Pd(II) complexes.•Characterization of the biarlys were by using GC–MS and 1H NMR.•Thermal studies indicate that ...catalysts are suitable for C–C coupling reactions.•OCMCS-3aPd and OCMCS-4aPd showed good activity in Suzuki coupling reactions.•Catalysts were highly efficient even after ten runs.
In this study, two new O-carboxymethyl chitosan Schiff bases supported Pd(II) catalyst were synthesized (OCMCS-3aPd and OCMCS-4aPd). The catalysts were characterized with FTIR, TG/DTG, SEM/EDAX, XRD, ICP-OES, UV–vis, magnetic moment and molar conductivity. The catalytic activities of these catalysts were tested in the synthesis of biaryl compounds by Suzuki cross-coupling reactions. Characterizations of the biaryls were performed with GC–MS and 1H NMR. In synthesis of the biaryl compounds in the presence of the Pd(II) catalyst, high selectivity was observed; no homo-coupling byproducts were detected in the spectra. A reusability test demonstrated that the catalysts were highly efficient even after ten run. The mercury poisoning and leaching tests indicated that the catalysts have heterogeneous nature.
In this study a new chitosan based water soluble Schiff base was produced through carboxymethylation of chitosan and its Pd(II) complex were synthesized and characterized by FTIR, 1H NMR, 13C CP-MAS ...NMR, TG/DTG, SEM/EDAX, XRD, ICP-OES, UV–Vis, magnetic moment measurements, molar conductivity measurements. The catalytic activity of the complex was tested in Suzuki coupling reactions for synthesis of biaryls containing various substrates. The identifications of the biarlys were performed by 1H NMR and GC–MS. The catalytic activity tests revealed that high selectivity was achieved with a small addition of the catalyst. Moreover by-product formation was not observed in the spectra of 1H NMR and GC–MS. Mercury poisoning and leaching test confirmed that the catalyst has heterogeneous character. The reusability tests showed that the catalyst did not lose its activity after six runs.
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•The catalyst showed high selectivity and high TON and TOF values.•Pd(II) catalyst exhibited longer lifetime and had higher thermal stability.•The chitosan supported catalyst has heterogeneous nature.
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•Catalase-like activity of biomaterial supported Pd catalyst decreased by only 12.9% at the end of 10 cycle.•Synthesis of biarlys using free solvent at 4min under MW was ...succeeded.•TON and TOF values for both applications determined high.•Suzuki reaction exhibited high selectivity and no homo-coupling by-products.
The aim of this study is to analyze the synthesis of a new chitosan supported Pd catalyst and examination of its catalytic activity in:
1.Suzuki coupling reactions by improving a simple, fast, and solvent-free microwave method.2.H2O2 decomposition reaction to find out its redox potential.
Pd catalyst was synthesized using chitosan as a biomaterial and characterized with FTIR, TG/DTG, XRD, 1H NMR, 13C NMR, SEM-EDAX, ICP-OES, Uv–vis spectroscopies, and magnetic moment, along with molar conductivity analysis. Biomaterial supported Pd catalyst indicated high activity and long life time as well as excellent turnover number (TON) and turnover frequency (TOF) values in Suzuki reaction. Biomaterial supported Pd catalyst catalyzed H2O2 decomposition reaction with considerable high activity using comparatively small loading catalyst (10mg). Redox potential of biomaterial supported Pd catalyst was still high without negligible loss (13% decrease) after 10 cycles in reusability tests. As a consequence, eco-friendly biomaterial supported Pd catalyst has superior properties such as high thermal stability, long life time, easy removal from reaction mixture and durability to air, moisture and high temperature.
In this study, mono-imine was synthesized (3a and 4a) via a condensation reaction between 2,4-pentadion and aminobenzoic acid (meta or para) in alcohol (1:1). The second-imine (CS-3a and CS-4a) was ...obtained as a result of the reaction of the free oxo groups of mono-imine (3a and 4a) with the amino groups on the chitosan (CS). Their structures were characterized with FTIR and (13)C CP-MAS. Then, the water soluble forms of CS-3a and CS-4a were obtained through oxidation of the hydroxide groups on the chitosan to carboxymethyl groups using monochloracetic acid (O-CMCS-3a · 2H2O and O-CMCS-4a · 2H2O). Thus, the solubility problem of chitosan in an aqueous media was overcome and Cu(II) complexes could be synthesized more easily. Characterization of the synthesized O-carboxymethyl chitosan Schiff base derivatives and their metal complexes, O-CMCS-3a-Cu(OAc)2 · 2H2O and O-CMCS-4a-Cu(OAc)2 · 2H2O, was conducted using FTIR, UV-Vis, TG/DTA, XRD, SEM, elemental analysis, conductivities and magnetic susceptibility measurements.
