Carbon-Coated Magnetic Iron Oxide Nanoparticles as Green Catalysts for Aromatic Nitration

2020 ◽  
pp. 2150008
Author(s):  
Meera Parthasarathy ◽  
Srikanth Adigopula ◽  
Harichandana Gownivari ◽  
Gnanaprasanna Mudhivedu ◽  
Anitha Vasudevan ◽  
...  

Nitration of aromatic compounds is an important industrial process, which creates significant environmental pollution because of the harsh mineral acid catalysts. In this work, we report the synthesis and application of magnetic iron oxide nanoparticles as green catalysts for aromatic nitration. Magnetic iron oxide nanoparticles were synthesized by co-precipitation method and tested for nitration reactions on selected aromatic substrates, phenol, benzaldehyde, methylbenzoate, [Formula: see text]-cresol and [Formula: see text]-cresol. For the nitration reactions, sodium nitrite was used as the nitro-source and hydrogen peroxide as the oxidant. Effect of reaction conditions like, solvent, temperature and microwave treatment were studied. The magnetic nanoparticles were found to be more stable after coating with a carbon shell by a one-pot carbonization method. The reactions were fast with good product yield under solvent-free microwave conditions. The nano-catalyst was recovered magnetically after the reaction and reused for three batches of nitration, without significant loss in catalytic activity. The nanoparticles were characterized using scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), X-ray diffractometry (XRD) and FTIR spectroscopy.

2019 ◽  
Vol 57 (3A) ◽  
pp. 160
Author(s):  
Minh-Tri Nguyen-Le ◽  
Dinh Tien Dung Nguyen ◽  
Sophia Rich ◽  
Ngoc Tram Nguyen ◽  
Cuu Khoa Nguyen ◽  
...  

Advances in nanotechnology in recent years has led to a number of diverse applications of nanomaterials. Magnetic iron oxide nanoparticles (Fe3O4 NPs), a representative of magnetic nanomaterials, has gained much attention of many researchers all over the world due to their unique properties such as superparamagnetism, biocompatibility and high magnetic saturation. With such properties, Fe3O4 NPs can be exploited in many fields, particularly biomedicine related fields such as cellular therapy, tissue repair, drug delivery, magnetic resonance imaging, hyperthermia and magnetofection. However, owing to their self-aggregation of Fe3O4 NPs, it is necessary to coat Fe3O4 NPs with a stable and biocompatible silica layer. Therefore, in this report, Fe3O4 NPs were synthesized via a co-precipitation method using iron (II)/ iron (III) chloride, ammonia and trisodium citrate. Then, the silica layer was coated onto Fe3O4 NPs through the hydrolysis and condensation of tetraethyl orthosilicate (TEOS) in ethanol. The as-synthesized samples were charaterized with the infrared (IR) spectroscopy, X-ray diffraction (XRD) spectroscopy, thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The results proved that silica was successfully coated on Fe3O4 NPs. The particle sizes measured by TEM were found to be about 12 nm in diameter for Fe3O4 NPs and 45 nm in diameter for silica coated Fe3O4 (SiO2@Fe3O4) NPs, while the dynamic diameters measured by DLS for Fe3O4 NPs and SiO2@Fe3O4 NPs were 15.7 and 65.8 nm, respectively. Both Fe3O4 NPs and SiO2@Fe3O4 NPs were superparamagnetic materials in which Fe3O4 NPs have higher magnetic saturation (45.8 emu/g) than the other (13.4 emu/g).This study examines the: ……...Advances in nanotechnology in recent years has led to a number of diverse applications of nanomaterials. Magnetic iron oxide nanoparticles (Fe3O4 NPs), a representative of magnetic nanomaterials, has gained much attention of many researchers all over the world due to their unique properties such as superparamagnetism, biocompatibility and high magnetic saturation. With such properties, Fe3O4 NPs can be exploited in many fields, particularly biomedicine related fields such as cellular therapy, tissue repair, drug delivery, magnetic resonance imaging, hyperthermia and magnetofection. However, owing to their self-aggregation of Fe3O4 NPs, it is necessary to coat Fe3O4 NPs with a stable and biocompatible silica layer. Therefore, in this report, Fe3O4 NPs were synthesized via a co-precipitation method using iron (II)/ iron (III) chloride, ammonia and trisodium citrate. Then, the silica layer was coated onto Fe3O4 NPs through the hydrolysis and condensation of tetraethyl orthosilicate (TEOS) in ethanol. The as-synthesized samples were charaterized with the infrared (IR) spectroscopy, X-ray diffraction (XRD) spectroscopy, thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), transmission electron microscopy (TEM) and dynamic light scattering (DLS). The results proved that silica was successfully coated on Fe3O4 NPs. The particle sizes measured by TEM were found to be about 12 nm in diameter for Fe3O4 NPs and 45 nm in diameter for silica coated Fe3O4 (SiO2@Fe3O4) NPs, while the dynamic diameters measured by DLS for Fe3O4 NPs and SiO2@Fe3O4 NPs were 15.7 and 65.8 nm, respectively. Both Fe3O4 NPs and SiO2@Fe3O4 NPs were superparamagnetic materials in which Fe3O4 NPs have higher magnetic saturation (45.8 emu/g) than the other (13.4 emu/g).


Author(s):  
Sema Salgın ◽  
Uğur Salgın ◽  
Nagihan Soyer

: In this study, magnetic iron oxide nanoparticles were synthesized by cost effective and an easy co-precipitation method. The effects of reaction parameters such as the mole ratio of Fe2+/Fe3+ (1/1, 1/2 and 1/3) and the base type (NaOH and NH4OH) on the average hydrodynamic diameter, zeta potential, chemical and morphological structure and saturation magnetization values of magnetic iron oxide nanoparticles were systematically investigated. Magnetic iron oxide nanoparticles synthesized at the mole ratio of 1/2 using NH4OH base gave better results in terms of particle size and particle shape, magnetization value. In order to prevent the formation of different phases in the co-precipitation method, an alternative approach was developed and the reaction was performed using inert supercritical CO2 atmosphere.


2013 ◽  
Vol 58 (4) ◽  
pp. 2011-2015 ◽  
Author(s):  
VERÓNICA PAREDES-GARCÍA ◽  
NÉSTOR TOLEDO ◽  
JULIANO DENARDIN ◽  
DIEGO VENEGAS-YAZIGI ◽  
CARLOS CRUZ ◽  
...  

2021 ◽  
Author(s):  
Sivakami M ◽  
Renuka Devi K ◽  
Renuka R

Abstract Green synthesis of nanoparticles is the method with eco-friendly, cost-effectiveness, and ease of resource availability approach. Nowadays, magnetic nanoparticles need increased due to its use in magnetic sensing, medical imaging, waste water treatment, and antibiotic drugs. In this report, the ecofriendly green synthesis of magnetic iron oxide nanoparticles were efficiently synthesized by using Murraya koenigii leaves extract. UV-visible spectrum revealed the surface Plasmon resonance band at 240 nm and analyzed the formation of iron oxide nanoparticles. X-ray diffraction pattern determined its high crystalline nature with strong intense peaks. Fourier Transform Infra-Red spectrum illustrated the Fe and O bonding stretching vibration. The particle size distribution graph showed the formed particles are in nanometer range. Transmission Electron Micrographs realized the spherical shaped iron oxide nanoparticles with its size at 10–25 nm. The energy dispersive X-ray spectrum and mapping analysis revealed the purity of prepared nanoparticles with only Fe and O presence. The vibrating sample magnetometer analysis showed the paramagnetic behavior of prepared magnetic iron oxide nanoparticles. The antimicrobial assay revealed potent inhibition of iron oxide nanoparticles on various human pathogens. The antioxidant, anti-inflammatory and anti-diabetic assays revealed the biomedical behavior of iron oxide nanoparticles.


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