Catalyst For Oxidation Of Sulfides Research Articles

Construction of Cobalt-Containing Polyoxovanadate-Based Inorganic-Organic Hybrids as Heterogeneous Catalysts for the Selective Oxidation of Sulfides.

In order to develop efficient catalysts for the selective oxidation of sulfides, in this work, two polyoxovanadate-based inorganic-organic hybrids, [Co(H2O)3(3-bpfb)0.5(V2O6)]·(3-bpfb)0.5 (1) and [Co(H2O)2(4-bpfb)0.5(V2O6)] (2) [3-bpfb = N, N'-bis(3-pyridylformamide)-1, 4-benzenediamine, 4-bpfb = N, N'-bis(4-pyridylformamide)-1, 4-benzenediamine], were isolated under hydrothermal conditions. The structures of 1 and 2 embodied two kinds of different cobalt-containing polyoxovanadate-based inorganic chains. Compound 1 contained a one-dimensional inorganic zigzag chain created by the aggregation of {V2O6} clusters with each other, on which Co (II) ions were fixed. But it was an inorganic dimeric chain constructed from two linear {V2O6} cluster-based chains gathered by Co (II) ions in 2. The 3-bpfb and 4-bpfb ligands, as the bidentate linkers, coordinated with two Co (II) ions from adjacent chains to organize them into two-dimensional layers. The hydrogen bonds made important contributions to the formation of supramolecular structures of the two compounds. The two compounds served as heterogeneous catalysts and exhibited efficient activity for the selective oxidation of sulfide to sulfoxide and could be reused at least six times without loss of catalytic activity and stability.

Keggin-type polyoxometalates/Amberlite nanocomposites as efficient catalysts for the aqueous oxidation of sulfides: Crucial roles of mono-iron and mono-manganese substituents

The condensation of Keggin-type polyoxometalates including H3PW12O40, H3PMo12O40, and their Mn(III) and Fe(III) derivatives with nano-structured Amberlite, nanoAmbN(Me)3Cl led to the formation of electrostatically immobilized polyoxometalates on the anion exchange polymer with a size less than ca. 70 nm. The nanocomposites were characterized by FT-IR, XRD, solid state diffuse-reflectance and solution UV–vis spectroscopy, TGA, BET and FESEM-EDX-Mapping and used for the oxidation of sulfides with periodate under aqueous and non-aqueous conditions. In spite of the small difference between the catalytic activity of H3PMo12O40 and H3PW12O40, the corresponding mono-iron and manganese substituted derivatives showed significantly different catalytic activities. Furthermore, nanoAmbN(Me)3@PW11MnO39 showed a high selectivity towards sulfone (72 %), compared to the highly chemoselective formation of sulfoxide in the presence of nanoAmbN(Me)3@PW11FeO39. NanoAmbN(Me)3@PW11FeO39 as the best catalyst of the series was recovered and reused at least six times for the oxidation of methyl phenyl sulfide. The increased catalytic activity of the iron-containing polyoxometalates than that of the corresponding manganese compounds was attributed to the Jahn-Teller distortion around the manganese(III) center.

Synergy between NiWO4 and chitosan for the development of catalysts for sulfide oxidation

In this work, catalysts based on composite films composed by chitosan with disordered NiWO4 (10, 20, and 40 % w/w) were synthesized for their application in the oxidation of sulfides to sulfones. The catalysts were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), optical profilometry, and contact angle measurements. Optimization of the catalytic conditions was performed using thioanisole as the standard molecule, resulting in optimal conditions of 50°C, 1 h, 10 mg catalyst loading, 8 equivalents of H2O2 as oxidant, and acetonitrile as solvent. The results obtained were superior to those with crystalline NiWO4 (highly ordered), highlighting the crystallinity of the system as a key factor in the development of new catalysts. The catalyst exhibited high stability over successive catalytic cycles, and scaling up to 50 times was achieved. Additionally, the reaction scope showed good conversion for a variety of different sulfides, indicating the robustness of the catalyst. Analysis of the catalytic mechanism through scavenger tests and spectroscopic probes revealed that reactive oxygen species (ROS) are responsible for the oxidation of sulfides to sulfones. Furthermore, it was observed that the synergy between NiWO4 and chitosan is crucial for the effective generation of ROS in this reaction.

A heterogeneous catalyst for oxidation of sulfides using a Mn(II) unsymmetrical Schiff base complex immobilized on MCM-41

An unsymmetrical Mn(II) Schiff base complex was attached to MCM-41. The synthesized catalyst was characterized by powder X-ray diffraction (XRD), nitrogen adsorption/desorption isotherms, inductivity coupled plasma (ICP), Fourier Transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The immobilized Schiff base complex was an efficient catalyst for oxidation of sulfides with hydrogen peroxide. In addition, this green oxidation system was used to oxidize various sulfides and the results showed that sulfoxides were the major products. Finally, the reuse of the catalyst was also investigated

Correction to “Thermoresponsive Polymeric Nanoparticles as Efficient Pickering Interfacial Catalysts for Selective Oxidation of Sulfides”

Correction to “Thermoresponsive Polymeric Nanoparticles as Efficient Pickering Interfacial Catalysts for Selective Oxidation of Sulfides”

Thermoresponsive Polymeric Nanoparticles as Efficient Pickering Interfacial Catalysts for Selective Oxidation of Sulfides

Thermoresponsive Polymeric Nanoparticles as Efficient Pickering Interfacial Catalysts for Selective Oxidation of Sulfides

Natural bentonite/cellulose/vanadium novel complex nanopolymer complex catalyst: Synthesis, characterization, and oxidation activity of several organic compounds

The first bentonite catalyst for oxidation of sulfides and oxidative coupling of thiols was fabricated. This novel catalyst was included natural bentonite, extracted cellulose from wheat wastes, and vanadium complex (Cell/Bent@V nanocomposite). It was characterized using SEM, TEM, ICP, AFM, XRD, XPS, and FT-IR. Further, oxidation of primary and secondary of alcohols were considered to show its catalytic potential for the various substrates. High yield, excellent conversion, and selectivity were observed for oxidation reactions catalyzed by Cell/Bent@V nanocomposite. Cel/Ben/V nanocomposite was shown the excellent stability and activity confirming by SEM, XRD, and FT-IR of recycled catalyst. Finally, the effect of ultrasonic irradiation instead of stirring on the oxidation reaction was evaluated. The high yields and conversions in the less times were observed.

3-(Sulfamic acid)-propyltriethoxysilane on biochar nanoparticles as a practical, biocompatible, recyclable and chemoselective nanocatalyst in organic reactions.

Recyclable and inexpensive catalysts, waste regeneration, use of available and safe solvents are important principles of green chemistry. Therefore, in this project, biochar nanoparticles (BNPs) were synthesized by the pyrolysis method from chicken manure. Then, 3-(sulfamic acid)-propyltriethoxysilane (SAPES) was immobilized on the surface of BNPs (SAPES@BNPs). The prepared catalyst (SAPES@BNPs) was used as a commercial, practical, biocompatible and reusable catalyst in the selective oxidation of sulfides to sulfoxides. Further, the catalytic application of SAPES@BNPs was explored in the multicomponent synthesis of tetrahydrobenzo[b]pyrans under mild and green conditions. BNPs were characterized using SEM, TGA and XRD techniques. SAPES@BNPs were characterized using SEM, FT-IR spectroscopy, WDX, EDS, TGA, and XRD techniques. Particle size distribution was obtained by histogram graph. SAPES@BNPs can be recovered and reused several times. The purity of the products was studied using NMR spectroscopy.

Nickel(II) unsymmetrical Schiff base complex immobilized into three dimensional mesoporous silica KIT-6: a novel and efficient catalyst for selective oxidation of sulfides to sulfoxides

Nickel(II) unsymmetrical Schiff base complex immobilized into three dimensional mesoporous silica KIT-6: a novel and efficient catalyst for selective oxidation of sulfides to sulfoxides

Catalysts based on nickel salt heteropolytungstates for selective oxidation of diphenyl sulfide

Abstract Nickel salts of Keggin heteropolytungstates with the general formula Ni x A y W12−y O39or40 (A = Si/P) were synthesized and studied as bulk catalytic materials or supported ones by deposition on modified and functionalized clay minerals (pillared layered clay and porous clay heterostructure). Characterizations by Raman, 31P and 29Si-NMR, and ESEM-EDS techniques showed that pure and supported systems preserved the Ni/W ratio and the expected structural properties of heteropolyanions. These materials were evaluated as catalysts in the selective oxidation of sulfides to sulfoxides or sulfones, using aqueous hydrogen peroxide and mild reaction conditions. The bulk materials, with a higher content of Ni, displayed a remarkable catalytic behavior in the oxidation of diphenyl sulfide (Ni3PW11NiO40H, 90% conversion in 15 min at 75°C, 100% sulfone selectivity in 3 h). Supported catalysts, particularly the non-functionalized PCH (Ni2SW12O40/PCH), showed excellent activity, with also being selective in the oxidation of sulfide to sulfoxide (87% conversion, 88.9% sulfoxide selectivity). The reuse of these materials was studied in the optimum reaction conditions, resulting in similar activity and selectivity.

Introducing Structural Diversity: Fe2(MoO4)3 Immobilized in Chitosan Films as an Efficient Catalyst for the Selective Oxidation of Sulfides to Sulfones

AbstractThis work reports how the immobilization of Fe2(MoO4)3 in chitosan films affects the oxidation reaction of sulfide derivatives to sulfates in the dark, resulting in good yields and excellent selectivity. As demonstrated, a variety of substituted sulfides were tolerated even in the presence of oxidative‐sensitive functional groups, leading to a regioselective application of the catalyst under mild reaction conditions and guaranteeing its reuse for at least 6 cycles without losing its catalytic performance. Specifically, films containing 1 mg of Fe2(MoO4)3 per ml of chitosan showed a yield and selectivity of 99 %. The key success of the selective oxidation was associated with the presence of the hydroxyl radical, ⋅OH, and the Fe3+/Fe2+ Fenton‐like process. As a proof of concept, the selective oxidation of sulfides to the corresponding sulfones was performed to demonstrate the synergistic effect between Fe2(MoO4)3 and chitosan. This work offers a design strategy for efficient catalysts that may extend to other semiconductors and oxidation processes.

Hollow Ag/Mn(btc): As highly efficient catalyst for oxidation of sulfides to sulfoxides

Hollow Ag/Mn(btc): As highly efficient catalyst for oxidation of sulfides to sulfoxides

PH-controlled assembling of POM-based metal–organic frameworks for use as supercapacitors and efficient oxidation catalysts for various sulfides

Two 3D POM-based metal–organic frameworks were prepared, which can be applied as electrode materials for supercapacitors, as well as efficient heterogeneous catalysts for the selective oxidation of sulfides to their corresponding sulfoxides.

New pyrimidine-amide-tetrazole ligand derived polyoxometalate-based copper complexes as catalysts for sulfide-sulfoxide transformation and electrochemical sensors

A new organic ligand was constructed by linking pyrimidine and tetrazole group through amide bond and used to build POM-based metal–organic complexes that can be used as catalysts for the catalytic oxidation of sulfides and electrochemical sensors.

Decagram-scale synthesis of heterometallic Ag/Ti cluster as sustainable catalyst for selective oxidation of sulfides

Atomically precise heterometallic clusters constitute a new family of model catalysts for understanding the fundamental catalysis process widely occurred in supported nanocatalysts, however, their syntheses and structure/composition modulations are nonetheless daunting challenges. Herein, three novel heterometallic Ag/Ti clusters with different Ag-doping ratios, Ag4Ti14, Ag4Ti6 and Ag4Ti2, have been readily synthesized in decagram-scale quantities through ligand engineering strategy. Thereinto, Ag4Ti2 can be efficiently prepared within 3 h in a quite high yield > 95 %. More remarkably, Ag4Ti2 shows unprecedented catalytic activity (>90 % conversion within 1 min) and selectivity (nearly 100 %) towards oxidation of thioethers with a wide substrate scope even including notorious 2-chloroethyl ethyl sulfide (CEES) at room temperature (turnover frequency = 11,880 h−1), which is mainly attributed to its full-surface-exposure-doping Ag atoms (affinity for binding of substrate) on TiO support and their cooperativity, whereas the other two are not the same case. Moreover, the Ag4Ti2 is highly robust in catalysis process and can be readily recovered and reused at least six cycles without observable loss of activity and selectivity, enabling this cluster hold great promise in industrial applications. This work not only establishes a general method to scale-up synthesis of Ag/Ti clusters but also provides an atom-precise model catalyst to understand the structure–property correlations of real-world conventional nanocatalysts such as silver doped-TiO2 nanoparticles.

Anderson-type polyoxometalate-based sandwich complexes bearing a new “V”-like bis-imidazole-bis-amide ligand as electrochemical sensors and catalysts for sulfide oxidation

By introducing a new “V”-like semirigid bis-imidazole-bis-amide ligand, 4,4’-bis(1<i>H</i>-imidazole-4-carboxamide)phenylmethane (L), into a reaction system containing Anderson-type polyoxoanions, three polyoxometalate-based metal–organic complexes (POMOCs) with different metal ions were successfully synthesized under solvothermal conditions. The as-prepared POMOCs [Zn₂L₂(H₂O)₄][Zn(H₂O)₂(TeMo₆O₂₄)]·9H₂O (<strong>1</strong>), [Ni(H₂O)₆][Ni₂L₂(H₂O)₂[AlMo₆(OH)₆O₁₈]₂]·9H₂O (<strong>2</strong>), and [Co(H₂O)₆][Co₂L₂(H₂O)₂[AlMo₆(OH)₆O₁₈]₂]·11.5H₂O (<strong>3</strong>) show sandwich-like supramolecular structures. Complexes <strong>2</strong> and <strong>3</strong> are isostructural, having two [ML(H₂O)₂]²⁺ chains with [AlMo₆(OH)₆O₁₈]³⁻ polyoxoanions as pendants arranged in an interdigital mode to construct the sandwich-like architecture, whereas in complex <strong>1</strong> the anionic [Zn(H₂O)₂(TeMo₆O₂₄)]⁴⁻ chain is sandwiched by two cationic [ZnL(H₂O)₂]²⁺ chains to generate the supramolecular structure. POMOCs <strong>1</strong>–<strong>3</strong> display excellent electrochemical sensing behavior for Cr(VI), Fe(III), BrO₃⁻, and NO₂⁻ ions and efficient catalytic performance in sulfide oxidation. The effect of the central metal on the electrochemical sensing and sulfide oxidation performance and that of the special architecture of <strong>1</strong> on the detection ability are discussed.

Tribromide immobilized on surface of magnetic nanoparticles modified tris(triazine-triamine): A versatile and highly active catalyst for oxidation of sulfides and oxidative coupling of thiols

In this article, we show that tribromide heterogenized on the surface of silica-coated magnetic nanoparticles modified with N2,N4,N6-tris(aminomethyl)-1,3,5-triazine-2,4,6-triamine [Fe3O4@SiO2-tris(triazine-triamine)-Br3] is a novel and efficient reusable nanocatalyst for the oxidation of sulfides to sulfoxides and oxidative coupling of thiols to disulfides using hydrogen peroxide as green oxidant. The structure of the as-fabricated Fe3O4@SiO2-tris(triazine-triamine)-Br3 was characterized by a series of spectroscopic techniques including FT-IR spectroscopy, SEM, TEM, EDX, VSM, XRD and TGA techniques. TEM and SEM analysis confirmed that the typical silica shell thickness was assessed to be around 20 nm. Recycling studies revealed that the Fe3O4@SiO2-tris(triazine-triamine)-Br3 could be easily recovered by a simple magnetic separation and recycled at least 6 times without deterioration in catalytic activity.

Hepta-Zr-Incorporated Polyoxometalate Assembly.

Driven by the synergistic-directing effect of the lacunary fragments, [B-α-GeW9O34]10- and [B-α-GeW11O39]8-, an unprecedented hepta-Zr-substituted polyoxometalate (POM) assembly K2Na6H10(Hpy)3[SbZr7O6(OH)4(B-α-GeW9O34)2(B-α-GeW11O39)2]·28H2O (1) was made under hydrothermal condition and structurally characterized. Of which, a unique hepta-Zr cluster, [SbZr7O6(OH)4]15+ core, was built by two trilacunary [B-α-GeW9O34]10- fragments and two monolacunary [B-α-GeW11O39]8- fragments and further arranged in a mode of a vertical cross and formed a pseudo-tetrahedron geometry. Compound 1 features the first Zr7-cluster-substituted POM. Moreover, 1 is an effective heterogeneous catalyst for the catalytic oxidation of sulfides into the corresponding sulfones with H2O2, manifesting distinguished conversion, excellent yield, and desired recyclability.

A highly efficient heterogeneous catalyst for selective oxidation of sulfides derived from an open-framework copper borovanadate containing a unique crown-shaped anion.

A novel 3D open-framework copper borovanadate with a unique crown-shaped anion [(VIVO)8(VVO)4B32O64(OH)8]12- and the largest ratio of Cu2+/borovanadate anions (6/1) has been successfully synthesized and systematically studied. The compound not only possesses high stability in a wide pH range of 3.2-10.8 (DMF solution), but also exhibits excellent catalytic activities for selective oxidation of sulfides.

Fabrication of La (III) supported on CoFe2O4 MNPs: a novel and efficient heterogeneous catalyst for selective oxidation of sulfides and synthesis of symmetrical disulfides

Fabrication of La (III) supported on CoFe2O4 MNPs: a novel and efficient heterogeneous catalyst for selective oxidation of sulfides and synthesis of symmetrical disulfides