RSM process optimization of biodiesel production from rapeseed oil and waste corn oil in the presence of green and novel catalyst.

In the scenario of global warming and pollution, the green synthesis and use of biodiesel has acquired utmost priority. Due to several limitations of homogeneous catalysis, organobase immobilized heterogeneous catalyzed production of biodiesel has come out as a favored route. The present report demonstrates the design and synthesis of Peganum harmala spice seed extract modified GO-CuFe2O4 (SSE@GO-CuFe2O4) nanocomposite as an organobase functionalized high surface area magnetic nanocatalyst. Pistachio leaves were used in the green reduction of precursor salts to synthesize CuFe2O4 NPs. The as-synthesized nanomaterial was characterized physicochemically by Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-Ray analysis (EDX), elemental mapping, transmission electron microscopy (TEM), X-Ray diffraction (XRD), thermogravimetric analysis (TGA) and vibrating sample magnetometer techniques (VSM). Subsequently, the catalyst was explored in the efficient synthesis of biodiesels by trans-esterification of two substrates, the rapeseed oil and waste corn oil. The optimum conditions for biodiesel production were determined through response surface methodology based on Box-Behnken design including the study of calibration curves and 3D contour plots. Easy separation and workup, use of green medium, excellent reused for several times and short reaction time are outstanding benefits of this study.

Biosynthesis of CuO nanoparticles using aqueous extract of herbal tea (Stachys Lavandulifolia) flowers and evaluation of its catalytic activity.

Plant derived biogenic synthesis of nanoparticles (NP) has been the recent trend in material science as featured sustainable catalysts. A great deal of the current nanocatalytic research has been oriented on the bio-inspired green catalysts based on their wide applicability. In this context, CuO NPs are synthesized following a green approach using an herbal tea (Stachys Lavandulifolia) flower extract. The phytochemicals contained in it were used asthe internal reductant without applying harsh chemicals or strong heat. The derived nanoparticles also got stabilized by the biomolecular capping. The as-synthesized CuO NPs was characterized over FT-IR, FE-SEM, EDS, TEM, XRD, TGA and UV-Vis spectroscopy. These NPs were exploited as a competent catalyst in the aryl and heteroaryl C-heteroatom (N, O, S) cross coupling reactions affording outstanding yields. The nanocatalyst was isolated and recycled in 8 consecutive runs with reproducible catalytic activity. Rigidity of the CuO/S. Lavandulifolia nanocomposite was further justified by leaching test and heterogeneity test.

Fabrication of Pd NPs on pectin-modified Fe3O4 NPs: A magnetically retrievable nanocatalyst for efficient C-C and C-N cross coupling reactions and an investigation of its cardiovascular protective effects.

The present report represents the synthesis of a novel Pd NPs immobilized over a natural polysaccharide (pectin) coated Fe3O4 magnetic nanocomposite material (Fe3O4@pectin/Pd) for investigating the cardiovascular protective effects. The biomolecular functionalization not only stabilizes the ferrite nanoparticles from agglomeration but also provides an environment for the biogenic reduction of Pd2+ ions. This protocol is a promising breakthrough for the synthesis of a quasi-heterogeneous catalyst, a bridge between heterogeneous and homogeneous medium. The structure, morphology and physicochemical properties of the material were characterized utilizing various analytical techniques like FT-IR, FE-SEM, TEM, VSM, EDX-elemental mapping, ICP, EDX and XPS. The catalyst showed excellent reactivity in C-C and C-N cross coupling reactions via Suzuki and Buchwald-Hartwig reactions respectively. An array of different biphenyls and aryl amines were then procured by reactions of various aryl halides with phenylboronic acid or secondary amines over the catalyst affording good to excellent yields. The catalyst was easily recoverable using an external magnet and thereafter recycled for several trials with insignificant palladium leaching or loss in catalytic performance. To investigate the cardiovascular protective activities of catalyst, the MTT assay was done on Human Aortic Endothelial Cells (HAEC), Human Coronary Artery Endothelial Cells (HCAEC), and Human Pulmonary Artery Endothelial Cells (HPAEC) cell lines. Nanocatalyst-treated cell cutlers significantly (p ≤ 0.01) decreased the caspase-3 activity, and DNA fragmentation. It raised the cell viability and mitochondrial membrane potential in the high concentration of Mitoxantrone-treated HAEC, HCAEC, and HPAEC cells. According to the above findings, nanocatalyst can be administrated as a cardiovascular protective drug for the treatment of cardiovascular diseases after approving in the clinical trial studies in humans.

In situ biogenic synthesis of Pd nanoparticles over reduced graphene oxide by using a plant extract (Thymbra spicata) and its catalytic evaluation towards cyanation of aryl halides.

An eco-friendly biosynthesized Pd NP anchored Thymbra spicata extract-modified graphene oxide (Pd NPs/rGO-T. spicata) nanohybrid material has been introduced. Initially, the herb, Thymbra spicata extract was immobilized on the surface of GO via their natural adhering capability. The polyphenolic function grafted in situ prepared RGO acted as the natural reductant of Pd precursor. The as-prepared nanocomposite (Pd NPs/rGO-T. spicata) was characterized using Fourier transform infrared (FTIR), UV-vis, X-ray diffraction (XRD), inductively coupled plasma (ICP), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), high resolution transmission electron microscopy (HRTEM), Fast Fourier Transform (FFT), Raman spectroscopy and EDX elemental mapping techniques. It has been observed that the Pd NPs with perfect crystal structure, uniform shape and size were dispersed homogeneously on the rGO surface. The material showed excellent water dispersibility due to the hydrophilicity of biomolecules attached over them, which is very essential in heterogeneous catalysis. The T. spicata contained biomolecules served as effective capping, reducing and stabilizing agents for the uniform immobilization of Pd precursors on graphene sheet surface without aggregation. The catalytic activity of this nano hybrid was assessed comprehensively in the cyanation of aryl halides with a wide range of substrates using K4[Fe(CN)6] as a cheap source of cyanide. The model reaction resulted outstanding catalytic performance with a great reusability of the catalysis.

Sonochemical in situ immobilization of Pd nanoparticles on green tea extract coated Fe3O4 nanoparticles: An efficient and magnetically recyclable nanocatalyst for synthesis of biphenyl compounds under ultrasound irradiations.

This work describes (i) an eco-friendly approach for in situ immobilization of Pd nanoparticles on the surface of Fe3O4 nanoparticles, with help of green tea extract and ultrasound irradiations, without using any toxic reducing agents and (ii) development of ultrasound assisted simple protocol for synthesis of biphenyl compounds. The structural, morphological and physicochemical characteristics of the catalyst were determined by different analytical methods including inductively coupled plasma (ICP) analysis, Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometry (VSM). Catalytic performance of Pd/Fe3O4 NPs as magnetic and heterogeneous catalyst was evaluated in synthesis of various biphenyl compounds throughout Suzuki coupling reactions by using the ultrasound-assisted method that was developed in this study. The Pd/Fe3O4 NPs demonstrated a noticeable catalytic activity by giving high product yields. Furthermore, the heterogeneous nanocatalyst was successfully recovered up to six times without significant activity loss. Additionally, with respect to conventional coupling reactions, the ultrasound-assisted synthesis reactions presented the advantages of green conditions, short reaction times, high yields and easier work-up.

In situ green synthesis of Ag nanoparticles on herbal tea extract (Stachys lavandulifolia)-modified magnetic iron oxide nanoparticles as antibacterial agent and their 4-nitrophenol catalytic reduction activity.

For first time, we designed an environment friendly technique novel hybrid magnetic nanocomposite with the potency of both reducing and stabilizing agent for immobilization of metal nanoparticles. Stachys lavandulifolia extract having a lot of carbonyl and phenolic hydroxyl functional groups can be applied in the Fe3O4 NPs modification. Furthermore, in aqueous solution, the complexation feasibility of polyphenols with silver ions can enhance the capacity and surface properties of the Fe3O4@S. lavandulifolia NPs for sorbent and in situ reduction of silver ions. So, as both the stabilizing and reducing agent, the novel magnetic nano-sorbent (Fe3O4@S. lavandulifolia NPs) has potential ability for silver nano particles immobilization to create a novel magnetic silver nanocatalyst. So that, no additional reductants, toxic reagents and intricate instruments are needed to prepare the catalyst. The morphology, structure, and physicochemical properties were elucidated by several analytical methods like, field emission scanning electron microscope (FESEM), high resolution transmission electron microscopy (HRTEM) images, energy-dispersive X-ray spectroscopy (EDS), vibrating sample magnetometer (VSM), X-ray diffraction analysis (XRD), X-ray photoelectron spectroscopy (XPS), FT-IR spectroscopy, and inductively coupled plasma (ICP). As recyclable nanocatalyst, Fe3O4@S. lavandulifolia/Ag indicated high catalytic activity for 4-nitrophenol (4-NP) reduction at ambient temperature. Ultimately, the Fe3O4@S. lavandulifolia/Ag antibacterial properties was examined against two bacteria (Staphylococcus aureus (Staph. aureus) and Escherichia coli (E. coli)) and indicated its antibacterial activities against gram negative (E. coli) bacteria and gram positive (Staph. aureus).

Green synthesis and characterizations of gold nanoparticles using Thyme and survey cytotoxic effect, antibacterial and antioxidant potential.

Nowadays, green chemistry methods are noticeable for synthesis metal nanoparticles due to affordable, easy and high reaction rate. In the present study gold nanoparticles (Au NPs) were eco-friendly synthesized using Thyme extract at the room temperature for 30 min to provide non-toxic, which can be used for different applications. Identifying properties of synthesized gold nanoparticles was done by various analytical technique including UV-Vis absorption spectroscopy approved presence of Au NPs in the solution, the functional groups of Thyme extract in the reduction and capping process of Au NPs are determined by FT-IR, Crystalline with the fcc plane approved by X-ray diffraction (XRD) pattern, energy dispersive spectroscopy (EDS) determined existence of elements in the sample, surface morphology, diverse shapes and size of present Au NPs were showed by scanning electron microscopy (SEM), atomic force microscopy (AFM) and Transmission electron microscopy (TEM). Beginning and end destroy temperature of the gold nanoparticles were determined by thermal gravimetric spectroscopy (TGA). In addition, antibacterial, antioxidant, and cytotoxicity properties of Au NPs were studied. Antibacterial activity of Au NPs was investigated on gram-positive (Bacillus) and gram-negative (Escherichia coli) by disk diffusion; also MIC (Minimum Inhibitory Concentration) and MBC (Minimum Bactericidal Concentration) were determined. DPPH free radical scavenging assay was used for antioxidant property and compared to butylated hydroxy toluene (BHT) as a standard antioxidant that showed high antioxidant activity. Synthesized Au NPs have great cell viability in a dose-depended manner and demonstrate that this method provided nontoxic for synthesis gold nanoparticles. The average diameter of synthesized Au NPs was about 35 nm.

Green synthesis of palladium nanoparticles mediated by black tea leaves (Camellia sinensis) extract: Catalytic activity in the reduction of 4-nitrophenol and Suzuki-Miyaura coupling reaction under ligand-free conditions.

The present study was conducted to synthesize palladium nanoparticles (Pd NPs) through a facile and green route using non-toxic and renewable natural black tea leaves (Camellia sinensis) extract, as the reducing and stabilizing agent. The as-prepared Pd@B.tea NPs catalyst was characterized by UV-vis spectroscopy, X-ray diffraction (XRD), fourier transformed infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). The Pd@B.tea NPs catalyst could be used as an efficient and heterogeneous catalyst for Suzuki coupling reactions between phenylboronic acid and a range of aryl halides (X=I, Br, Cl) and also the reduction of 4-nitrophenol (4-NP) using sodium borohydride in an environmental friendly medium. Excellent yields of products were obtained with a wide range of substrates and the catalyst was recycled 7 times without any significant loss of its catalytic activity.