Ultrasound-promoted green approach for the synthesis of sulfonamides using natural, stable and reusable Natrolite nanozeolite catalyst at room temperature

Optimized Preparation of Nanosized Hollow SSZ-13 Molecular Sieves with Ultrasonic Assistance

Because of its unique eight-membered ring pore structure and the arrangement of cations in its structure, the SSZ-13 molecular sieve has a higher affinity for CO2 than other gases, meaning it has attracted more attention than other porous materials for CO2 adsorption. However, the expensive template and long preparation time limits the industrial production of SSZ-13. In this work, a hollow structure was successfully introduced into the nanosized SSZ-13 molecular sieve with ultrasonic treatment. The effects of the amount of seed added and the ultrasonic time on the structure were investigated. When the amount of seed added was 0.5 wt.% and the ultrasonic time was 60 min, the sample showed a hollow cubic crystal with a diameter of about 50 nm. The specific surface area reached 791.50 m2/g, and the mesoporous ratio was 66.3%. The samples were tested for CO2 adsorption performance at 298 K. It was found that the hollow sample prepared in this work has higher CO2 adsorption capacity compared with the SSZ-13 zeolite prepared with conventional methods. When the adsorption pressure was 0.27 bar, the adsorption amount reached 2.53 mmol/g. The hollow SSZ-13 molecular sieve reached a CO2 adsorption capacity of 4.24 mmol/g at 1 bar.

Utilization of plant-derived Myricetin molecule coupled with ultrasound for the synthesis of gold nanoparticles against breast cancer

Phytochemical mediated synthesis of nanoparticles has gained great interest in the field of cancer therapeutics. We attempted a simple and stable synthesis of gold nanoparticles (AuNPs) with Myricetin (Myr) adopting ultrasound-assisted method. Further, we evaluated anticancer activity of the synthesized nanoparticles. The physico-chemical properties of biosynthesized Myr-AuNPs were characterized by UV-visible spectrophotometer, Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and particle size analysis. The study reports of Myr-AuNPs showed spherical-shaped particles with a size of < 50 nm. Stability of the particles was increased in various physiological media. Furthermore, the graph theoretical network analysis of Myr-AuNPs indicated that the probable binding with the mTOR is an effective target for breast cancer cells. In silico molecular docking study of Myr-AuNPs in human mTOR kinase was found to be strong binding. The IC₅₀ value of Myr-AuNPs was calculated as 13 μg mL^-1 against MCF-7 cell line. The AO/EB and DAPI stainings confirmed the anticancer activity by Myr-AuNPs-treated cells showed a good proportion of dead cells evidenced with formation of pro-apoptotic bodies. In addition, Myr-AuNPs exhibited depolarization of mitochondrial membrane potential and production of reactive oxygen species. This study proves that Myr-AuNPs holds great promise to use against breast cancer as a potent anticancer drug. Graphical abstract A schematic representation for the biosynthesis of Myr-AuNPs.

Systematic comparison of sono-synthesized Ce-, La- and Ho-doped ZnO nanoparticles and using the optimum catalyst in a visible light assisted continuous sono-photocatalytic membrane reactor

In the present work, La-ZnO, Ho-ZnO and Ce-ZnO nanoparticles were synthesized by sonochemical method to use as catalysts in visible light photocatalysis, sono-photocatalysis and visible light sono-photocatalysis/membrane separation (SPMS) processes for degradation of an organic pollutant. The effect of doping source, mass ratio of doping source to the precursor of ZnO synthesis, pH, sonication temperature and time, and calcination temperature and time was investigated in visible light photocatalytic activity of the prepared lanthanides-doped ZnO nanoparticles using Taguchi design. The optimum conditions for the nanoparticles synthesis were obtained at 8 wt% of cerium nitrate, pH 10, sonication time for 1 h at 60 °C and calcination for 3 h at 300 °C. FE-SEM, EDS, XRD, PL and DRS analyzes were used to identify the characteristics of Ce-ZnO as the optimum catalyst. The Ce-ZnO nanoparticles were used to remove Reactive Orange 29 (RO29) solution via sono-photocatalysis process under the visible light irradiation. The effect of initial pH of solution, catalyst dosage, light intensity (power of applied lamp(s)), initial concentrations of inorganic salts such as Na₂CO₃, NaCl and Na₂SO₄ on the decolorization efficiency was investigated. Finally, a continuous flow visible light SPMS reactor was used in the presence of Ce-ZnO catalyst and polypropylene hollow fiber membrane for treatment of dye solution. In the best conditions of SPMS reactor, 97.84% of dye removal was achieved. GC-Mass, COD and TOC analyses were used to approve degradation and mineralization of RO29 using the SPMS process. Moreover, the prepared Ce-ZnO nanocomposite was shown the favorable antibacterial behavior against positive and negative bacteria.

Rapid ultrasound assisted hydrothermal synthesis of highly pure nanozeolite X from fly ash for efficient treatment of industrial effluent

Nanoporous green materials like nanozeolite has been in focus for their superb efficiency to treat industrial wastewater. The study reports ultrasound assisted hydrothermal method as a very fast method to convert industrial fly ash from different sources of eastern India to nanozeolite X for efficient removal of toxic dyes and metals from industrial effluent. The pure nanosized zeolite X was synthesized rapidly at 20 min of ultrasound treatment after alkali fusion. The efficiency of nanozeolite X was determined in terms of the adsorption capacity towards various divalent ions such as Zn²⁺, Cu²⁺, Cd²⁺, Pb²⁺, Ni²⁺, Ca²⁺, and Mg²⁺ as well as various dyes such as methylene blue, crystal violet, indigo carmine, and Congo red. In comparison to commercially available microporous Zeolite X (a maximum of 120.43 mg g^-1 for Pb²⁺ and 134.62 mg g^-1 by for methylene blue), all synthesized nanozeolite X shows high adsorption capacity for metals (a maximum of 196.24 mg g^-1 for Pb²⁺) as well as dyes (193.45 mg g^-1 for methylene blue). Highly pure nanozeolite X has shown immense potential for treatment of real time industrial wastewater.

A review of engineering aspects of intensification of chemical synthesis using ultrasound

Cavitation generated using ultrasound can enhance the rates of several chemical reactions giving better selectivity based on the physical and chemical effects. The present review focuses on overview of the different reactions that can be intensified using ultrasound followed by the discussion on the chemical kinetics for ultrasound assisted reactions, engineering aspects related to reactor designs and effect of operating parameters on the degree of intensification obtained for chemical synthesis. The cavitational effects in terms of magnitudes of collapse temperatures and collapse pressure, number of free radicals generated and extent of turbulence are strongly dependent on the operating parameters such as ultrasonic power, frequency, duty cycle, temperature as well as physicochemical parameters of liquid medium which controls the inception of cavitation. Guidelines have been presented for the optimum selection based on the critical analysis of the existing literature so that maximum process intensification benefits can be obtained. Different reactor designs have also been analyzed with guidelines for efficient scale up of the sonochemical reactor, which would be dependent on the type of reaction, controlling mechanism of reaction, catalyst and activation energy requirements. Overall, it has been established that sonochemistry offers considerable potential for green and sustainable processing and efficient scale up procedures are required so as to harness the effects at actual commercial level.

Effect of low frequency ultrasound on the surface properties of natural aluminosilicates

Structural and surface properties of different natural aluminosilicates (layered, chain and framework structural types) exposed of 20 kHz ultrasound irradiation (0-120 min) in aqueous and 35 wt%. aqueous H2O2 dispersions were studied by X-ray diffraction (XRD), dynamic light scattering (DLS), nitrogen adsorption-desorption, thermal analysis, and Fourier transform infrared spectroscopy (FTIR) techniques. It was confirmed that sonication caused slight changes in the structure of investigated minerals whereas their textural properties were significantly affected. The aqueous dispersions of montmorillonite (Mt), clinoptilolite (Zlt), glauconite (Glt) and palygorskite (Pal) were represented by several particles size fractions according to DLS-study. Ultrasound irradiation produced a decrease of the average particle diameter by 4-6 times in water and by 1.3-5 times in H2O2 dispersions except for Pal, which underwent strong agglomeration. A significant increase of total pore volume and pore diameter was observed for Glt sonicated in H2O2 dispersions whereas for Pal mainly micropore volume sharply increased in both aqueous and H2O2 dispersions.

Ultrasound-promoted one-pot three component synthesis of tetrazoles catalyzed by zinc sulfide nanoparticles as a recyclable heterogeneous catalyst

Ultrasound irradiation was applied for the appropriate and rapid synthesis of 1-substituted tetrazoles through cyclization reaction of various primary amines, sodium azide and triethyl orthoformate. This reaction was effectively catalyzed by ZnS nanoparticles as an efficient, recoverable and reusable catalyst. Compared with conventional methods, this method has the considerable advantages such as shorter reaction times, easier work-up, purer products with high yields and mild conditions. The ZnS nanoparticles catalyst is an excellent instance to replace Brønsted acids for the preparation of 1-substituted tetrazole derivatives in very short reaction times with excellent yields. The catalyst can be recovered and reused several times without significant loss of its catalytic activity.

Green synthesis of Pd/CuO nanoparticles by Theobroma cacao L. seeds extract and their catalytic performance for the reduction of 4-nitrophenol and phosphine-free Heck coupling reaction under aerobic conditions

We report the green synthesis of palladium/CuO nanoparticles (Pd/CuO NPs) using Theobroma cacao L. seeds extract and their catalytic activity for the reduction of 4-nitrophenol and Heck coupling reaction under aerobic conditions. The catalyst was characterized using the powder XRD, TEM, EDS, UV-vis and FT-IR. This method has the advantages of high yields, elimination of surfactant, ligand and homogeneous catalysts, simple methodology and easy work up. The catalyst can be recovered from the reaction mixture and reused several times without any significant loss of catalytic activity.

Preparation of carbon supported CuPd nanoparticles as novel heterogeneous catalysts for the reduction of nitroarenes and the phosphine-free Suzuki–Miyaura coupling reaction

This paper reports on the synthesis and use of C/CuPd bimetallic NPs as heterogeneous catalysts for the phosphine-free Suzuki–Miyaura coupling and the reduction of nitroarenes.

Preparation of Au nanoparticles by Anthemis xylopoda flowers aqueous extract and their application for alkyne/aldehyde/amine A3-type coupling reactions

This paper reports on the green synthesis of gold nanoparticles (Au NPs) by Anthemis xylopoda flowers aqueous extract without the addition of surfactant agents and their application as stable catalysts for the synthesis of propargylamines.

Green synthesis of a natrolite zeolite/palladium nanocomposite and its application as a reusable catalyst for the reduction of organic dyes in a very short time

A natrolite zeolite/palladium (natrolite zeolite/Pd) nanocomposite has been successfully synthesized applying a simple in situ reduction method using an aqueous extract of fruits of Piper longum as a reducing and stabilizing agent.

Synthesis and catalytic activity of carbon supported copper nanoparticles for the synthesis of aryl nitriles and 1,2,3-triazoles

Various substituted aryl nitrile and 1,2,3-triazole derivatives were prepared by using carbon supported copper nanoparticles (C/Cu NPs) as a heterogeneous catalyst under ligand-free conditions, which provided good to excellent yields.

Synthesis, characterization, structural, optical properties and catalytic activity of reduced graphene oxide/copper nanocomposites

This paper reports on the synthesis and use of copper nanoparticles supported on reduced graphene oxide, as separable catalysts for N-arylation of phenylurea with aryl halides under ligand-free and microwave conditions. Also, the structural and optical properties are studied.

Green synthesis, optical properties and catalytic activity of silver nanoparticles in the synthesis of N-monosubstituted ureas in water

We report the green synthesis of silver nanoparticles by using Euphorbia condylocarpa M. bieb root extract for the synthesis of N-monosubstituted ureas in water. UV-visible studies show the absorption band at 420 nm due to surface plasmon resonance (SPR) of the silver nanoparticles. This reveals the reduction of silver ions (Ag+) to silver (Ago) which indicates the formation of silver nanoparticles (Ag NPs). This method has the advantages of high yields, simple methodology and easy work up.

Copper Iodide Nanoparticles-Catalysed Cyanation of Aryl Halides Using Non-Toxic K4[Fe(CN)6] in the Presence of 1,2-Bis(5-Tetrazolyl)Benzene as an Efficient Ligand

Cyanation of aryl bromides were carried out with K4[Fe(CN)6] in the presence of catalytic amounts of a copper salt and 1,2-bis(5-tetrazolyl)benzene as a ligand under thermal conditions. This method has the advantages of high yields, simple methodology and easy work up.

Copper Complex-catalysed C–N Coupling Reaction of Aryl Iodides with Nitrogen-containing Heterocycles

An efficient method for the copper-catalysed arylation of nitrogen-containing heterocycles is reported using 3-(diphenylphosphino) propanoic acid as a ligand in combination of CuCl. The C–N coupling reactions afford various N-arylated products in good to excellent yields.

CoFe2O4 Nanoparticles as a Magnetically Recoverable and Reusable Catalyst for the Synthesis of Arylaminotetrazoles and 5-aryloxytetrazoles

An efficient and direct method is described for the synthesis of 5-arylamino-1 H-tetrazoles (Isomer A) or 1-aryl-5-amino-1 H-tetrazoles (Isomer B) and 5-aryloxytetrazoles from arylcyanamides or cynates with nano CoFe2O4 as a reusable and efficient heterogeneous catalyst. Isomer A was obtained from arylcyanamides carrying electron-withdrawing substituents on the aryl ring, while isomer B was produced with electron-releasing groups. The significant advantages of this methodology are high yields, elimination of dangerous and harmful hydrazoic acid, simple work-up procedure and the recovery and reusability of the catalyst.