Nanocrystalline zeolite beta and zeolite Y as catalysts in used palm oil cracking for the production of biofuel

Nanocrystalline zeolites with crystal size smaller than 100 nm are potential replacement for conventional zeolite catalysts due to their unique characteristics and advantages. In this study, the synthesis of nanocrystalline zeolite Y (FAU) and nanocrystalline zeolite beta (BEA) under hydrothermal conditions is reported. The effect of crystal size on the physico-chemical characteristics of the zeolite, Y (FAU), and beta (BEA) is reported. The properties of nanocrystalline zeolites Y and Beta with crystal size around 50 nm are compared with the microcrystalline zeolite Y and microcrystalline zeolite beta, respectively. The performance of the nanocrystalline zeolite as a catalyst was investigated in the cracking of used palm oil for the production of biofuel. The nanocrystalline zeolite catalytic activity was compared with the activity of microcrystalline zeolite in order to study the effect of crystal size on the catalytic activity. Both nanocrystalline zeolites gave better performance in terms of conversion of used palm oil as well as selectivity for the formation of gasoline fraction. The increase in surface area and improved accessibility of the reactant in nanocrystalline zeolites enhanced the cracking activity as well as the desired product selectivity.     

Spectroscopic investigations on Tb3+ doped lead fluoroborate glasses

This article presents the optical properties of Tb³⁺ in lead fluoroborate glasses of the type X PbF₂·(89–X)B₂O₃·10 Al₂O₃·1Tb₂O₃ (where X=8, 12, 16, 20, 24, 28, 34 and 36). The standard Judd–Ofelt model was applied to the room temperature absorption intensities of Tb³⁺ (4 f⁸) to determine the phenomenological intensity parameters Ω₂, Ω₄ and Ω₆. These parameters have been used to calculate radiative transition probabilities (A_rad), lifetimes (τ_R) and branching ratios (β_R) for the excited level ⁵D₄. The predicted values of τ_R are compared with the measured values for ⁵D₄ level for eight glass compositions (Glass (A–H)). Among the eight-terbium glasses Glass A with 8 mol% of PbF₂ (as the optimum content) has revealed an intense green emission with maximum life time and higher quantum efficiency. The stimulated emission cross section σ(λ_P) is also evaluated for the ⁵D₄→⁷F_J (J=6, 5, 4 and 3) transitions.     

An efficient protocol for the synthesis of highly sensitive indole imines utilizing green chemistry: optimization of reaction conditions

Novel and highly sensitive indole-based imines have been synthesized. Their synthesis has been compared employing a variety of protocols. Ultimately, a convenient, economical and high yielding set of conditions employing green chemistry have been designed for their synthesis.     

Urine NMR Metabolomic Study on Biochemical Activities to Investigate the Effect of P. betle Extract on Obese Rats

Applied Biochemistry and Biotechnology - The present studies are to evaluate the ability of PB to induce weight loss and urine metabolite profile of Piper betle L. (PB) leaf extracts using...     

Chemically modified screen-printed electrodes as efficient potentiometric sensors for cyclobenzaprine hydrochloride determination in pure and pharmaceutical preparations

Chemically modified screen-printed electrodes (SPEs) with 3,4-dihydroxy-9,10-dioxo-2-anthracenesulfonic acid sodium salt [Alizarin Red (ALZ.R)] and tricresylphosphate (TCP) were fabricated and examined for potentiometric determination of cyclobenzaprine hydrochloride (CZP.HCl) in pure and pharmaceutical samples. The content of ALZ.R in the prepared SPEs varied, which significantly affected their potentiometric response during CZP.HCl estimation. The measured potential value was dependent on the pH of the studied solution. A stable modified SPE sensor was prepared with reproducible readings within 22 days. A wide linear concentration range could be measured with Nernestian slope value of 60.12 ± 0.18 mV decade⁻¹. Based on the recorded analytical parameters of these modified SPEs, a sensitive and reliable detection of CZP.HCl in pharmaceutical samples could be attained.     

A reliable study for extensions of the Bratu problem with boundary conditions

In this paper, we present a reliable study on extensions of the Bratu problem with boundary conditions. The work rests mainly on Adomian decomposition method and Padé approximants. The study shows a variety of approximations, one for each extension. The work highlights the effect of the extensions on the structure of the approximate solutions. Copyright © 2012 John Wiley & Sons, Ltd.     

Facile synthesis,crystal growth,characterization and computational study of new pyridine-based halogenated hydrazones: Unveiling the stabilization behavior in terms of noncovalent interactions

The pyridine-based halogenated hydrazone derivatives (E)-N′-benzylidene-2-[(6″-chloroazin-2″-yl)oxy]acetohydrazide ( 6a ), (E)-N′-(3′-chlorobenzylidene)-2-[(6″-chloroazin-2″-yl)oxy]acetohydrazide ( 6b ) and (E)-N′-(3′-bromobenzylidene)-2-[(6″-chloroazin-2″-yl)oxy]acetohydrazide ( 6c ) have been obtained using 6-chloro-2-hydroxypyridine. The structure of the products ( 6a – c ) has been verified using X-ray crystallography and spectroscopic approaches. A single-crystal X-ray diffraction (SC-XRD) investigation showed that the structures are stabilized by intermolecular attractive forces. Additionally, density functional theory (DFT) has been adopted to explore the structural properties, vibrational spectra, noncovalent interactions and frontier molecular orbitals using the B3LYP/6-311 + G(d,p) level. The nonlinear optical properties of the title compounds were calculated using the CAM-B3LYP/6-311 + G(d,p) level. Frequency analysis confirmed the stability of the molecules, and an excellent correlation was observed between the DFT- and SC-XRD-based structural parameters. The SC-XRD analysis confirmed that the dimers of 6a , 6b and 6c are linked by hydrogen-bonding interactions. Natural bond orbital (NBO) analysis also reconfirmed the strength of intermolecular hydrogen-bonding and hyperconjugative interactions. NBO investigation was also utilized to analyze the atomic charges. Moreover, Fourier transform infrared and natural population analyses endorsed that there are significant N&bond;H⋅⋅⋅O&dbond;C hydrogen-bonding linkages in dimeric structures of the compounds. The hydrogen-bonding network and different sorts of hyperconjugative interactions are the main reasons for the stability of the products in the solid state. The highest occupied and lowest unoccupied molecular orbital energies and first-order nonlinear optical properties of these molecules are reported. The quantum chemical parameters were derived using frontier molecular orbital energies.     

PIXE data analysis by two-dimensional correlation mapping techniques: Analysis of chloride and sulfate ions attack in homemade mortar samples

Chloride and sulfate ions ingress behaviors in concrete are more complex and complicated processes than can be described by Fick's law of diffusion. A new approach based on two-dimensional correlation mapping (2D-CM) and particle-induced X-ray emission (PIXE) spectra was successfully applied to describe their transportation process. The use of hybrid 2D correlation enabled a fast comparison of ions ingress, whereas multiple perturbation correlation spectroscopy enabled the study of compositional factor affecting the ingress process. It was shown that by rearranging the same data in different ways, different techniques of 2D-CM could be applied and new information could be derived. The 2D-CM findings were in line with the classical PIXE analysis and consistent with the underlying physics of the experiments, which suggested that it will be a powerful and fast data analysis tool for PIXE spectra.     

Synthesis of new 4-methyl-3-piperidones via an iron-catalyzed intramolecular tandem isomerization–aldolisation process

A new versatile synthesis of 3-piperidones is described, starting from amino acids. It uses, as a key step, an iron carbonyl-mediated intramolecular tandem isomerization–aldolisation reaction. These new heterocycles appear as useful scaffolds for the total synthesis of various types of bioactive molecules.