Eco-friendly Heterogeneous Catalyst Research Articles

Preparation of nanodiamond anchored on copper tannic acid as a heterogenous catalyst for synthesis of 1,4-benzodiazepines derivatives

In this research, a new and eco-friendly heterogeneous catalyst (ND@Tannicacid-Cu) was synthesized based on nanodiamond and copper tannic acid via esterification process. The as-prepared catalyst was characterized by Fourier transforms infrared spectroscopy (FT-IR), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and X-ray diffraction (XRD) methods. The catalytic efficacy of the intended catalyst was examined by one-step three-component reaction of 1,4-benzodiazepine derivatives from a mixture of ortho-phenylenediamine, aromatic aldehydes, and dimedone under mild conditions. In all instances, corresponding 2,4-benzodiazepines derivatives were synthesized with high efficiency, short reaction time, straightforward work up procedure, no requirement for column-chromatography, and cost-effective catalyst. The heterogeneous catalyst was easily recycled using fillers, and it can be reused for eight cycles without significantly diminishing its performance.

Intercalation of Well-Dispersed Fe2 O3 with SnO2 toward Durable Peroxymonosulfate Activation to Eliminate Antibiotics: Performance and Mechanism.

Sustainable Fe2 O3 /SnO2 with fine interfacial feature derived from FeSnO(OH)5 was prepared and employed for elimination contaminants. The synergistic effect between Fe2 O3 and SnO2 endowed a remarkable degradation performance for tetracycline degradation. Well dispersed SnO2 can function as fine protective layer to enhance the anchoring of iron ions. In addition, SnO2 with excellent conductivity can accelerate electron transfer on the surface of Fe2 O3 , further activation PMS. Approximately 89.3% of tetracycline (TC) was removed in Fe2 O3 /SnO2 /PMS system, which was higher than alone Fe2 O3 /PMS (73.2%) and SnO2 /PMS (39.7%) systems. The operating parameters were evaluated and studied. Electron paramagnetic resonance (EPR) and quenching tests manifested that 1 O2 was primary active specie, and ⋅OH, ⋅SO4 - and ⋅O2 - were participated in the degradation process. Besides, degradation pathways were proposed by identifying the intermediate products. This work is expected to offer a potential design for construction eco-friendly heterogeneous catalyst toward wastewater treatment.

Retraction Note: The synthesis of SBA-Pr-3AP@Pd and its application as a highly dynamic, eco-friendly heterogeneous catalyst for Suzuki–Miyaura cross-coupling reaction

Retraction Note: The synthesis of SBA-Pr-3AP@Pd and its application as a highly dynamic, eco-friendly heterogeneous catalyst for Suzuki–Miyaura cross-coupling reaction

New ecofriendly heterogeneous nano-catalyst for the synthesis of 1-substituted and 5-substituted 1H-tetrazole derivatives

A novel ecofriendly heterogeneous catalyst containing Schiff base coordinated Cu(II) covalently attached to Fe3O4@SiO2 nanoparticles through imidazolium linker [Fe3O4@SiO2-Im(Br)-SB-Cu (II)] was synthesized and characterized by using various techniques. The catalytic efficiency of this nano-catalyst was tested in water in the synthesis of tetrazole derivatives using two one-pot multicomponent reaction (MCR) models: The synthesis of 1-aryl 1H-tetrazole derivatives from the reaction of aniline, triethyl orthoformate, and sodium azide and the synthesis of 5-aryl 1H-tetrazole derivatives from the reaction of benzaldehyde, hydroxy amine hydrochloride, and sodium azide. The investigation showed that (i) The catalyst is highly efficient in the synthesis of tetrazole derivatives with high yield (97%) in aqueous medium and mild temperatures; (ii) The catalytic effectiveness is due to the synergy between the metallic center and the imidazolium ion and (iii) The reuse advantage of the catalyst without contamination or significant loss (12% of loss range) in the catalytic activity.

Reduction in Free Fatty Acid Concentration in Sludge Palm Oil Using Heterogeneous and Homogeneous Catalysis: Process Optimization, and Reusable Heterogeneous Catalysts

Acid catalysts including Amberlyst 15 and sulfuric acid were used for heterogeneous and homogeneous catalyst reactions respectively, to reduce high free fatty acid (FFA) in sludge palm oil (SPO) using an esterification process. The goal of this research was to reduce high FFA content in SPO to less than 1 wt.% FFA so that it can be employed as a raw material in a transesterification process to produce biodiesel. Amberlyst 15 is an eco-friendly catalyst with many benefits, such as being reusable and generating non-toxic waste after reactions, compared to homogeneous catalysts, although the reaction time of the homogeneous catalyst was faster than the heterogeneous catalytic reaction. Therefore, esterification reactions with a heterogeneous and homogeneous catalytic reaction were carried out to examine conversion of FFA. The heterogeneous catalytic reaction decreased the FFA content from 89.16 wt.% to 1.26 wt.% under the recommended conditions of 44.7 wt.% methanol, 38.6 wt.% Amberlyst 15 catalyst loading, and 360 min reaction time. For homogeneous catalytic reaction, the FFA content of 1.03 wt.% was achieved under the recommended conditions of 58.4 wt.% methanol, 16.8 wt.% sulfuric acid, and 79.7 min reaction time. Furthermore, the results of the reusability research demonstrate that the heterogeneous catalyst may be reused for at least nine cycles. This research showed the promising potential of using SPO non-edible oil for biodiesel production by employing an eco-friendly heterogeneous catalyst for cost-effective environmental remediation.

Pd/RHA and Pd/BPA as Eco-Friendly Heterogeneous Catalysts: Microwave-Assisted C–S Cross-Coupling Reaction in DMF

AbstractFirst time, Pd-Rice Husk Ash (Pd/RHA) and Pd-Banana Peel Ash (Pd-BPA) were used as eco-friendly catalysts in the C–S cross-coupling reaction of 5-bromo-2,1,3-benzothiadiazole with various benzene thiols in DMF under microwave irradiation at 75 °C, 200 W (100 psi) for 15–25 min. These catalysts were produced from agro-industrial wastes, such as rice husk ash and banana peel ash. These can be recycled and reused up to five catalytic cycles without loss of catalytic efficiency.

Hybrid Alginate-Brushite Beads Easily Catalyze the Knoevenagel Condensation On-Water.

An innovative hybrid organic–inorganic material composed of alginate–brushite xerogel beads was successfully applied for the catalysis of the Knoevenagel condensation. The catalyst was derived from phosphated alginate xerogel microspheres formed from the ionotropic gelling effect of phosphated alginate. To this end, alginate was phosphated by the addition of diammonium hydrogen phosphate in a 1% w/w alginate gel. The phosphated alginate was subsequently precipitated by chelation of Ca2+ cations, generating a phosphated alginate hydrogel microsphere, which was washed and dried, forming hybrid organic–inorganic xerogel beads as a crystalline phosphate-rich mineral fraction covered by alginate. X-ray diffraction analysis revealed that the crystalline inorganic matrix of the material was composed predominantly of brushite. SEM analysis revealed plate-like, ribbon-like, or needle-like morphologies in the hybrid alginate–brushite beads. The hybrid material was tested as a catalyst for Knoevenagel condensation, which was performed ″on-water″ under mild conditions with aromatic aldehydes and activated methylene compounds, giving high yields (up to 97%). The reaction rate and product yield increased together with the reaction temperature for all reagents. The recyclable solid catalyst was effective for three runs, revealing the potential of the innovative hybrid catalyst as an eco-friendly heterogeneous catalyst.

One-pot multi-component synthesis of five substituted tetrahydropyridine derivatives promoted by a new natural-based biopolymeric catalyst as a green, reusable and eco-friendly heterogeneous catalyst

One-pot multi-component synthesis of five substituted tetrahydropyridine derivatives promoted by a new natural-based biopolymeric catalyst as a green, reusable and eco-friendly heterogeneous catalyst

Recent Progresses in the Multicomponent Synthesis of Dihydropyridines by Applying Sustainable Catalysts Under Green Conditions.

The synthesis of dihydropyridines, valuable molecules with diverse therapeutic properties, using eco-friendly heterogeneous catalysts as a green alternative received significant consideration. By selecting appropriate precursors, these compounds can be readily modified to induce the desired properties in the target product. This review focused on synthesising diverse dihydropyridine derivatives in single-pot reactions using magnetic, silica, and zirconium-based heterogeneous catalytic systems. The monograph describes preparation techniques for various catalyst materials in detail. It covers facile and benign magnetic, silica, zirconium-based, and ionic liquid catalysts, exhibiting significant efficacy and consistently facilitating excellent yields in short reaction times and in a cost-effective way. Most of the designated protocols employ Hantzsch reactions involving substituted aldehydes, active methylene compounds, and ammonium acetate. These reactions presumably follow Knoevenagel condensation followed by Michael addition and intra-molecular cyclisation. The multicomponent one-pot protocols using green catalysts and solvents have admirably increased the product selectivity and yields while minimising the reaction time. These sustainable catalyst materials retain their viability for several cycles reducing the expenditure are eco-friendly.

Waste Musa paradisiaca plant: An efficient heterogeneous base catalyst for fast production of biodiesel

Exploration of economically viable and environmentally benign solid base-catalyzed transesterification of oil is extremely important to significantly reduce the cost of biodiesel. In this study, heterogeneous base catalysts from the peel, trunk and rhizome of Musa paradisiaca (Malbhog) were prepared by burning the dry materials followed by calcination at 550 °C for 2 h. The catalysts were investigated for biodiesel production using jatropha oil as a feedstock. Catalysts were characterized using powder X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FT-IR), Brunauer–Emmett–Teller (BET), Energy dispersive X-ray (EDX), Field emission scanning electron microscope (FESEM), X-ray photoelectron spectrometer (XPS) and HRTEM (High resolution transmission electron microscope). EDX and XPS studies exhibited that M. paradisiaca trunk catalyst possessed higher potassium content than the peel and rhizome catalysts. M. paradisiaca trunk catalyst displayed better efficacy which yielded 97.65% of biodiesel at 65 °C only in 9 min of reaction time using 5 wt % of catalyst and 9:1 MTOR (methanol to oil ratio). Basicity of catalyst was found in the increasing order of 1.39 mmol g−1 (rhizome) < 1.43 mmol g−1 (peel) < 1.59 mmol g−1 (trunk) with turnover frequency of 46.16 min−1 (rhizome) < 56.85 min−1 (peel) < 68.24 min−1 (trunk). Activation energies using M. paradisiaca peel, trunk and rhizome catalysts were found to be 48.68, 47.56 and 48.93 kJ mol−1. All the three catalysts from the waste M. paradisiaca plant are contributing almost similar activities in the catalysis with remarkable efficacies. The catalyst was successfully reused up to the 3rd reaction cycle with 91.23% of biodiesel yield. Biodiesel was characterized using FT-IR, 1H NMR, 13C NMR and GC-MS. Biodiesel properties and its (Na + K) and (Ca + Mg) concentrations were found to be within the limit of ASTM D6751 and EN 14214 standards. This study will provide a low-cost, renewable and eco-friendly heterogeneous base catalyst for efficient biodiesel production at a large-scale.

Enhanced heterogeneous Fenton-like degradation of refractory organic contaminants over Cu doped (Mg,Ni)(Fe,Al)2O4 synthesized from laterite nickel ore

The heterogeneous Fenton-like catalyst (Mg,Cu,Ni)(Fe,Al)2O4 was synthesized via a coprecipitation method using laterite nickel ore leaching solution as raw material. The effects of CuCl2·2H2O addition and calcination temperature on the microstructures and degradation properties of the obtained products were investigated. Results showed that higher calcination temperature could promote the migration of Cu2+ ions from CuO to the spinel ferrite lattice and occupied octahedral sites. The degradation efficiencies (η) of various types of low-concentration dyes and tetracycline were higher than 95%, which was mainly due to the accelerated generation of OH radicals by the synergistic effect of Fe3+ and Cu2+ ions in octahedral sites of the formed (Mg,Cu,Ni)(Fe,Al)2O4. Moreover, after five consecutive degradation cycles, the η of RhB was still close to 100%, TOC removal efficiency was maintained around 40% and the concentrations of metallic ions in degraded solutions were all lower than the national effluent discharge standard (GB8978-1996), confirming the as-obtained (Mg,Cu,Ni)(Fe,Al)2O4 was an eco-friendly heterogeneous Fenton-like catalyst with excellent stability and reusability. This study may provide an effective reference for large scale preparing efficient heterogeneous Fenton-like catalysts from natural minerals in treating the wastewater contaminated by refractory organics.

The Synthesis of SBA-15-Pr-3AP@Pd and its Application as a Highly Dynamic, Eco-Friendly Heterogeneous Catalyst for Suzuki-Miyaura Cross-Coupling Reaction

The Synthesis of SBA-15-Pr-3AP@Pd and its Application as a Highly Dynamic, Eco-Friendly Heterogeneous Catalyst for Suzuki-Miyaura Cross-Coupling Reaction

Investigation of snail shell waste as potential and eco-friendly heterogeneous catalyst for synthesis of 1-(benzothiazolylamino) methyl-2-naphthols derivatives

Abstract From a sustainable point of view, available in Morocco and cheaper, we recycled the snail shell waste (aragonite) as a potential and an eco-friendly heterogeneous catalyst for the development and the synthesis of 1-(benzothiazolylamino) methyl-2-naphthols derivatives, via one-step condensation of three reactants of the substituted aromatic aldehydes, β-naphthol with 2-aminobenzothiazole under solvent-free conditions at 85 °C. The characterization of the products (4a-g) was carried out by different analysis techniques such as: Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (1H NMR and 13C NMR), high resolution mass spectrometry (HRMS) and elementary analysis. The investigations of the snail shell waste in organic reactions were showed excellent yields, very short times, ease of handling, positive aspects, great stability, reuse and environment respect, respectively.

RETRACTED ARTICLE: The synthesis of SBA-Pr-3AP@Pd and its application as a highly dynamic, eco-friendly heterogeneous catalyst for Suzuki–Miyaura cross-coupling reaction

The hexagonal mesoporous organic–inorganic hybrid as a new nanocatalyst was prepared by the treatment of SBA-15 with (3-chloropropyl)triethoxysilane, the 2,4,6-triamino pyrimidine ligand, and then PdCl2 to obtain the SBA-15-propyl-triamino pyrimidine@Pd called as SBA-Pr-3AP@Pd, which was examined through Suzuki–Miyaura cross-coupling reaction by several aryl halides and phenylboronic acid under mild conditions in high yield.

Transesterification of commercial waste cooking oil into biodiesel over innovative alkali trapped zeolite nanocomposite as green and environmental catalysts

Four types of green alkali modified clinoptilolite (K, Na, Ca, and Mg) were prepared using green tea extracts as novel types of eco-friendly heterogeneous basic catalysts in the transesterification of commercial waste cooking oil into biodiesel. The modified products displayed significant enhancement in the total basicity, surface area, ion exchange capacity, and the morphological properties. The modified samples of K/clinoptilolite (K/Clino), Na/clinoptilolite (Na/Clino), Ca/clinoptilolite (Ca/Clino), and Mg/clinoptilolite (Mg/Clino) showed promising catalytic activities achieving biodiesel yields of 93.6%, 95.2%, 96.4%, and 98.7%, respectively. The best yields were recognized using 4 wt, % as catalysts loading, 16:1 as methanol-to waste oil molar ratio, and at 70 °C as temperature. The best transesterification intervals were identified at 120 min, 120 min, 180 min, and 150 min for K/Clino, Na/Clino, Ca/Clino, and Mg/Clino, respectively. The modified products also demonstrated high reusability properties and the resulted biodiesel in their transesterification systems are of technical properties within the accepted limits of EN 14214 and ASTM D-6751 standards.

Trisaminomethane–cobalt complex supported on Fe3O4 magnetic nanoparticles as an efficient recoverable nanocatalyst for oxidation of sulfides and C–S coupling reactions

In this work, trisaminomethane–cobalt complex immobilized onto the surface of Fe3O4 magnetic nanoparticles was successfully prepared via a simple and inexpensive procedure. The prepared nanocatalyst was considered a robust and clean nanoreactor catalyst for the oxidation and synthesis of sulfides under green conditions. This ecofriendly heterogeneous catalyst was characterized by Fourier transform infrared spectroscopy, X‐ray diffractometry, energy‐dispersive X‐ray spectroscopy, inductively coupled plasma‐atomic emission spectroscopy, thermogravimetric analysis, vibrating sample magnetometry, X‐ray mapping, scanning electron microscopy, and transmission electron microscopy techniques. Use of green medium, easy separation and workup, excellent reusability of the nanocatalyst, and short reaction time are some outstanding advantages of this method.

Facile fabrication, characterization and efficient photocatalytic activity of surfactant free ZnS, CdS and CuS nanoparticles

In this research, some metal sulfide nanoparticles (NPs) including ZnS, CdS and CuS NPs were prepared by a simple and low-cost co-precipitation method for the photocatalytic degradation of Bromothymol blue dye (BTB) under natural sunlight irradiation. The synthesized materials were characterized by XRD, FT-IR, UV-vis DRS, PL, TGA, SEM and TEM techniques for the investigation of structural, electronic, thermal, and morphological properties. The optical absorption and the band gaps of the ZnS, CdS, and CuS NPs were calculated as 3.62 eV, 2.21 eV, and 1.16 eV from the UV-vis DRS. XRD results demonstrate the cubic structure of ZnS NPs, CdS NPs, and the hexagonal structure of CuS NPs in the polycrystalline nature. The spherical shape and size of the NPs are observed in the range of 5–12 nm from the XRD and TEM analysis. The FTIR spectra reveal that the functional groups are associated with the synthesized materials by the metal-sulfur (Zn-S, Cd-S, and Cu-S) vibration bands. The CdS NPs exhibited a more efficient photocatalytic activity for the BTB dye degradation than the ZnS and CuS NPs. Similarly, the results on the photostability for the degradation of BTB indicate that the CdS NPs exhibited the activity and stability for up to 5 cycles which are better than those of the ZnS and CuS NPs, consistent with their tiny size and extremely effective reacting surface area. Hence, the semiconducting materials are expected to have the potential as a highly efficient, cost-effective and eco-friendly heterogeneous catalyst for industrial applications.

Catalytic synthesis of organic cyclic carbonate through CO2 fixation and production of β-amino alcohol via ring opening of epoxides under green condition by polystyrene embedded Al(III) catalyst

Development of low cost, eco-friendly heterogeneous catalyst for the production of value added organic compounds has been drawn a considerable attention to the synthetic chemists in recent era. Keeping the above idea in our mind, we have design and synthesized a polymer anchored Al(III) composite from modified Merrifield resin. The composite was characterized properly by FT-IR spectra, SEM, EDAX, elemental analysis, ICP-AES and PXRD studies. The low cost material is very efficient heterogeneous catalyst for the production of fine organic chemicals such as organic cyclic carbonates and 2-amino alcohols under green and mild reaction conditions. Organic cyclic carbonates were synthesized through the insertion of carbon dioxide into epoxides at room temperature under solvent free condition. The developed protocol of catalytic synthesis of cyclic carbonates is sustainable, eco-friendly and cost-effective. Moreover atmospheric carbon dioxide is utilized here. Besides, the catalyst is very much efficient to produce 2-amino alcohol from ring opening of epoxides by nucleophilic attack of amine under solvent free condition and at room temperature. This polymer anchored Al(III) can be recovered and reused easily. The catalyst preserved its catalytic intensity even after use of eight successive catalytic cycles.

Chitosan–silica sulfate nanohybrid: a highly efficient and green heterogeneous nanocatalyst for the regioselective synthesis of N-alkyl purine, pyrimidine and related N-heterocycles via presilylated method

The presilylation of purine and pyrimidine nucleobases as well as other related N-heterocycles with HMDS utilizing chitosan–silica sulfate nanohybrid (CSSNH) is described. CSSNH is proved to be a useful, highly efficient and eco-friendly heterogeneous nanohybrid catalyst for silylation of nucleobases. The presilylated nucleobases then underwent the reaction with different sources of carbon electrophiles to afford the desired N-alkyl-substituted derivatives in good-to-excellent yields. CSSNH exhibits several advantageous involving ease of handling and preparation, low cost, reusability and environmental benignity. These unique properties render the CSSNH to be an ideal candidate for use in green industrial processes.

Pyridiniumporphyrazinato oxo-vanadium tribromomethanide as a new source of Br+ catalyst for the chemo and homoselective oxidation of sulfides and benzylic alcohols

The present study describes the design and synthesis of novel nano N-bromo porphyrazin (N-bromo tetra-2,3-pyridiniumporphyrazinato oxo-vanadium tribromomethanide [VO(TPPABr)] CBr3) as an efficient, recyclable and thermal stable heterogeneous catalyst for chemo and homoselective oxidation of sulfides to sulfoxides and benzyl alcohols to benzaldehydes. This ecofriendly heterogeneous catalyst was fully characterized by FT-IR spectra, UV–Vis spectra, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermal gravimetric analysis (TGA), energy-dispersive X-ray spectroscopy (EDX) and elemental analysis (CHN). The synthesized catalyst exhibited a high-performance and considerable reusability.