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Prussian blue (transition metal mixed valence complex) has been accomplished as an eco-friendly and efficient for the synthesis of high quality biodiesel production using Watermelon (Citrullus vulg...

The dysprosium (Dy) (1.12, 2.24, 3.33 and 4.02 at.%) modified zinc oxide (ZnO) nanoparticles were synthesized by simple chemical co-precipitation method. The prepared nanoparticles were analyzed by EDAX, TEM, FTIR, EPR, VSM and dielectric studies. The energy dispersive analysis of X-rays confirms the presence of Dy, Zn and O in the prepared samples. The transmission electron micrographs of the prepared samples show that the particles are spherical in nature with average size 22–18 nm. The shifting of Zn–O peak towards lower frequency side in the FTIR spectra of the prepared samples confirms the substitution of Dy ion in the ZnO lattice. EPR investigations exhibit paramagnetic signals at g- 1.956, 2.04 and 2.323. The magnetic properties of the synthesized Dy doped ZnO NPs reveal weak ferromagnetic behavior. The studies on electrical properties of the prepared samples provided new and interesting information on the contribution of grains, grain boundaries and interfacial polarization on dielectric parameters and electrical conductivity.

Ce-doped ZnO nanoparticles (NPs) with different Ce doping concentrations (0, 0.96, 1.96, 2.52 and 3.12 at.% of Ce) were prepared by the chemical co-precipitation method. Energy-dispersive analysis of X-rays confirms the presence of Ce in Ce-doped ZnO nanoparticles. Raman spectra revealed the hexagonal wurtzite structure of pure and Ce-doped ZnO nanoparticles and presence of various defects. The photoluminescence spectra exhibited enhanced violet and blue emission peak intensities for 0.96 at.% of Ce, while broad band green emissions decreased with Ce content. Electron paramagnetic resonance (EPR) studies revealed the presence of oxygen vacancies (V O), zinc vacancies (V Zn) and Ce3+ ions in the prepared ZnO nanoparticles. VSM studies showed room temperature ferromagnetism (RTFM) in the Ce-doped ZnO NPs. The substituted Ce3+ions found to induce RTFM along with V O, V Zn in correlation with the results obtained from the EPR, PL and Raman studies. The variation of dielectric constants (e r), dielectric loss (e″) and ac conductivity (σ ac) as a function of frequency and Ce concentration is studied using ‘Maxwell–Wagner Model.’

The reaction kinetics of Prussian blue (PB)/NaNO2 initiated for the nitration of phenols by in aqueous bisulfate and acetonitrile medium indicated first-order dependence on [phenol], [NaNO2], and [PB]. An increase in [KHSO4] accelerated the rate of nitration under otherwise similar conditions. The rate of nitration was faster in the solvent of higher dielectric constant (D). Observed results were in accordance with Amis and Kirkwood plots [log k′ vs. (1/D) and [(D − 1)/(2D + 1)]. These findings together with the linearity of plots, log k′ versus (vol% of acetonitrile (ACN)) and mole fraction of (nx) ACN, probably indicate the importance of both eloctrostatic and nonelctrostatic forces, solvent–solute interactions during nitration of phenols. Reaction rates accelerated with the introduction of electron-donating groups and retarded with electron-withdrawing groups, which are interpreted by Hammett's theory of linear free energy relationship. Hammett's reaction constant (ρ) is a fairly large negative (ρ < 0) value, indicating attack of an electrophile on the aromatic ring. Furthermore, an increase in temperature decreased the reaction constant (ρ) values. This trend was useful in obtaining isokinetic temperature (β) from Exner's plot of ρ versus 1/T. Observed β value (337.8 K) is above the experimental temperature range (303–323 K), indicating that the enthalpy factors are probably more important in controlling the reaction.

Ultrasonic sonication and microwave irradiation exhibited pronounced effects on crystalline Mn(II) carbonate catalyzed biodiesel production using watermelon (Citrullus vulgaris) seed oil and alcohol (fibrous flesh) as exclusive green feedstock. Both ingredients, alcohol and oil, necessary for biodiesel production are extracted from watermelon fruit. Mn(II) carbonate and watermelon fruit, which are used for transesterification, are inexpensive, easily available and environmentally safe. The reactions occurred smoothly under conventional conditions and afforded good product yields. However, microwave assisted and ultrasonically assisted reactions exhibited highly significant reduction in reaction times with a trend: microwave assisted (35 min) << ultrasonically assisted (2.0 h) << conventional (8.0 h). The whole exercise is operationally simple, environmentally safe, energy saving, time saving and green, which fits well into the green chemical principles of Anastas and Warner.

Zeolite Y was found to be an efficient catalyst for a facile nitration of aromatic compounds with acetonitrile as the solvent in the presence of small amounts of HNO3 at room temperature. The reactions afforded mono-nitro derivatives of aromatic compounds in about three hours under stirred conditions with high yields and regioselectivity. The reaction times drastically reduced to about 20 min under sonication and to about 20 s under microwave irradiation. Zeolite is recovered after completion of the reaction and recycled for three to four times without any problem. The approach is particularly appropriate for the conversion of unsaturated cinnamic acids into nitrostyrenes.

Ultrasonic and microwave-assisted practical methods have been developed for the nitration of phenols using metal nitrates in aqueous polyethylene glycol (PEG) media. Solvent is recycled three times for reproducibility. It was recycled with minimum loss and decomposition. Developed protocols were cost effective, simple and efficient, which afforded nitration products in good to excellent yields. The observed hyperchromic/hypochromic shifts in the UV/VIS spectra of metal nitrates in PEG solutions could be due to the plausible in situ formation of “PEG-bound M(II) nitrate” and thereby the release of nitronium ion () during the course of reaction when metal nitrate [M(II)nitrate] is added to PEG. Nitronium thus formed most likely is captured by aromatic compound to afforded nitro aromatics.

This research work presents the synthesis, characterization, evaluation of the antibacterial and anticancer activity of ZnO nanopowders prepared by solution combustion method using the bio fuels Punica granatum L and Tamarindus indica L. The X-ray diffractograms of all the samples revealed the hexagonal Wurtzite structure with the standard JCPDS pattern of zincite [36–1451]. Surface morphology of the samples was studied by SEM. Particle shapes and sizes were determined by TEM. Qualitative phytochemical screening of the aqueous fruit extracts of Punica granatum L and T. indica L revealed the presence of many phyto-components in them. Toxicity of the nanopowders was tested on Gram-negative Escherichia coli MTCC 7410 and Pseudomonas aeruginosa MTCC 7903 by disk diffusion method. Minimum inhibitory concentration was determined by microbroth dilution technique. Anticancer activity of ZnO powders was tested against breast cancer cell line MCF-7 by MTT assay. The cytotoxicity was assessed by hemolytic activity.

Pure and erbium (1.30, 1.79, 2.83 and 3.53 at. %) doped ZnO nanoparticles are synthesized by wet chemical co - precipitation method. The synthesized s amples are characterized by powder X - ray diffraction (XRD), energy - dispersive analysis of X - rays (EDAX), transmission electron microscopy (TEM), Raman spectroscopy, UV - visible diffusion reflectance spectroscopy (DRS) and LCR Impedance spectroscopy. The XRD measurements confirmed the hexagonal wurtzite structure of all samples and size of the particle is found to be decreased with Er content. TEM images show spherical shape with more agglomeration in Er doped ZnO nanoparticles. Raman spectra confirmed the he xagonal wurtzite structure of pure and Er doped ZnO nanoparticles with E 2 (high) mode at 438 cm - 1 and presence of other possible defects. UV - visible DRS shows decrease in the band gap with increasing Er 3+ in ZnO host. Dielectric constant, dielectric loss f actor and ac conductivity properties were decreased with Er

Thiocyanation of various aromatic and heteroaromatic compounds has been studied using Zeolite H-SDUSY Powder (CBV720) as catalyst and ammonium thiocyanate (NH4SCN) as thiocyanation reagent in aceto...

Prussian blue triggered transesterification of ethylacetoacetate with various alcohols underwent efficiently. The reaction is mild, eco-friendly, and selective with good yields. The proposed reaction pathway depicts the formation of an intermediate by the interaction of β-ketoesters with catalytic site of the Prussian blue, followed by nucleophilic attack of the alcohol at the electrophilic center followed by successive elimination of the proton to give the product. Observed longer reaction times under conventional conditions reduced amazingly under sonication and microwave irradiation followed enhanced yield of products.

Transesterification of β-ketoesters with different alcohols has been studied under conventional and unconventional conditions using the simple desktop chemical cesium carbonate as catalyst. These methods enabled transesterification of β-ketoesters in good yields with dramatic rate acceleration and reduced reaction times. The procedures which used unconventional methods, for example sonication and microwave irradiation, are highly promising compared with conventional procedures.

Nitration of aromatic compounds and cinnamic acids with oxalylchloride/DMF afforded the corresponding nitro derivatives in the presence of KNO3 or NaNO2 under conventional and nonconventional (ultrasonic and microwave) conditions. The present methodology offers several benefits such as excellent yields, simple work-up procedure, and short reaction times. The yields obtained under present methodology are comparable with those obtained from (POCl3/DMF/KNO3 or NaNO2) and (SOCl2/DMF/KNO3 or NaNO2) systems followed by shorter reaction times. The reaction times of sonication and microwave conditions are very shorter than those of the conventional conditions.

Transesterification of β-ketoesters with various alcohols has been studied under conventional and non-conventional conditions using desktop chemicals such as Mn(II) salts as catalysts. These methods offered transesterification of β-ketoesters in good yields with dramatic rate accelerations and reduced reaction times. The developed protocols under nonconventional methods such as sonication and microwave irradiation are highly promising compared with the existing procedures.

Cd1 − xFexTe single crystals were prepared by vapour phase growth method in the composition range of 0 ≤ x ≤ 0.03. Chemical analysis, surface morphology, structural investigations and electrical properties were carried out by EDAX, SEM, XRD, TEM and transport technique, respectively. Microscopic variations between the target and actual compositions were noticed. Morphology studies revealed that dislocation aided growth is active in the present crystals. TEM and XRD studies confirmed that the samples of all compositions crystallized in zinc blende structure, and the lattice parameters varied almost linearly decreases with Fe content. At room temperature, the resistivity of the Cd1 − xFexTe crystals of all compositions (x = 0.01, 0.015, 0.02, 0.025 and 0.03) lies in the range of 3.5–6.5 M Ω, the activation energies lie in the range of 63–133 meV, and the samples were show the ‘p’ type conductivity.

The optical and electrical properties of vapour phase grown crystals of diluted magnetic semiconductor Zn 1 − x Cr x Te were investigated for 0 ≤ x ≤ 0.005. The diffuse reflectance spectra exhibited an increase in the fundamental absorption edge ( E 0 ) with composition x and were also dominated by a broad absorption band around 5200 cm − 1 arising from 5 T 2 → 5 E transition. The 5 T 2 and 5 E levels originate from the crystal field splitting of the 5 D free ion in the ground state. The electrical resistivity measurements revealed semiconducting behaviour of the samples with p-type conductivity in the temperature range of 200–450 K.

Single crystals of Zn1−xCrxTe were grown by vapour phase growth method in the composition range of 0⩽x⩽0.005. Chemical analysis, surface morphology, structural and microhardness studies were carried out by EDAX, SEM, XRD and Vicker's indentation techniques, respectively. Microscopic variations between the target and actual compositions were noticed. Morphology studies revealed that dislocation aided growth is active in the present crystals. XRD studies showed that samples of all compositions crystallized in zinc blende structure, and the lattice parameters varied linearly with x following Vegard's law. Vicker's hardness (Hv) decreased exponentially with x.

Pure and Er (2, 3 and 4 at. %) doped ZnO nanoparticles have been synthesized by chemical co-precipitation method. EDS spectrum confirmed the presence of Zn, O and Er in the synthesized samples. The XRD measurements confirmed the hexagonal wurtzite structure of ZnO for all samples. The crystallite size of the samples decreases with increase in concentration and are compatible with the results that obtained from TEM analysis.EPR spectra exhibitedferromagnetic signals the substitution Er The possible ferromagnetic zinc interstials signal is appeared for 2 at. % of Er dopant. The room temperature ferromagnetic is observed only for 2 at. % of Er while all other samples exhibiting weak ferromagnetic nature.

Polyvinylpyrrolidone capped ZnO and Nd (0.5 and 1 at.%) ZnO nanoparticles have been prepared by chemical co-precipitation method in aqueous media. The as-prepared nanoparticles were subjected to compositional, structural, morphological and photoluminescence studies. EDS confirmed the presence of Nd element in ZnO nanoparticles. X-ray diffraction patterns and TEM studies established that pristine and Nd doped ZnO nanoparticles exhibited wurtzite crystal structure. The average particle size obtained from the XRD and TEM were in good agreement with each other. Photoluminescence studies on Nd doping amplify the defect related emission.

Since conventional conditions require reaction times of 16-24h, the transformation of β-keto ester (I) is investigated under ultrasound or microwave conditions where the latter afford optimal results concerning the time.

Metal-mediated condensation of o-phenylenediamine with bisacetylacetone-ethylenediimine yields 14-membered tetraaza macrocyclic six-coordinate complexes of the type [M(mac)Cl2],[M(mac)SO4·H2O] (where M = FeII, CoII and CuII; mac = macrocyclic ligand formed in the template reaction). The metal ions are coordinated by four azomethine nitrogen atoms bridged by acetylacetone moieties. The electrical conductance magnetic moments, electronic and IR spectral data of all complexes are discussed.

The rate of interparticle vanadium transfer in FCC catalysts as a function of the degree of oxidation of the steaming environment has been determined. The rate of interparticle vanadium transfer is low when the atmosphere in the steamer is reducing, but increases dramatically as the mole % excess oxygen becomes greater than zero. High rate of vanadium transfer is accompanied by a greater loss of surface area and catalytic activity. XPS measurements show that the oxidation state of vanadium increases from +3 when the steamer atmosphere is reducing to +5 when the % excess oxygen is greater than zero. Surface vanadium concentration follows a similar trend. In addition, data from a commercial resid FCCU operating in a partial burn were analyzed. The results of the analyses show that defining a partial burn operation with the flue gas CO/CO 2 ratio is not adequate for characterizing the vanadium oxidation state. Carbon on regenerated catalyst is a better marker for the vanadium oxidation state in the regenerator.