Nanostructured Colloidal Solutions of Malachite Green Formulated: Nonlinear Optical Properties and Simulation

Journal of Fluorescence - Malachite green (MG) is a dye that has been presented to use as photosensitizers for photodynamic therapy (PDT). Nonlinear absorption coefficient (β) and nonlinear...     

MCM-41-SO3H: an efficient,reusable, heterogeneous catalyst for the one-pot,three-component synthesis of pyrano[3,2-b]pyrans

Research on Chemical Intermediates - MCM-41-SO3H, ordered mesoporous silica material MCM-41 with covalently anchored sulfonic acid groups, was used as a solid acid catalyst for the convenient,...     

Influence of ionic liquid counterions on activity and selectivity of ethylene trimerization using chromium-based catalysts in biphasic media

In recent years ionic liquids (ILs) have attracted much interest because of their widespread use in various fields. Several trimerization and oligomerization catalysts have been evaluated in ILs with different organic–inorganic hybrid structures. High catalytic activity and selectivity, easy product separation, and recycling of the catalyst are the advantages of a biphasic catalyst system compared to the homogeneous catalysts. In this study, the influence of IL counter-anions on activity and selectivity of the ethylene trimerization catalysts based on Cr-SNS-R was investigated. All synthesized materials were characterized using Fourier-transform infrared spectroscopy, ¹H NMR, ¹³C NMR, UV–Vis. spectroscopy, thin-layer chromatography, and elemental analysis (CHNS). In ethylene trimerization reaction, the dodecyl substituent in the SNS ligand exhibited better activity and selectivity than the butyl substituent. The results revealed that the presence of BF₄⁻ as a counter-anion in the IL led to an increase in activity and selectivity compared to Br⁻ and I⁻ counter-anions. It was found that the BF₄⁻ counter-anion plays a conclusive role in the development of 1-hexene activity and selectivity to a maximum amount of 71,132 g_1-C6/(g_Cr × h) and more than 99%, respectively. Finally, the catalyst was reused thrice without losing its 1-hexene selectivity.     

Intramolecular cyclization of <Emphasis Type="Italic">N</Emphasis>-propargyl anilines: a new synthetic entry into highly substituted indoles

Indole derivatives are an important class of heterocycle found in a large number of natural products and synthetic pharmaceuticals. Given the low cost and easy availability of N-propargyl anilines, synthesis of indole cores from these versatile structural motifs has attracted a lot of attention in the past decade. In this review, we summarize the most representative and interesting reports on this rapidly advancing area, with special emphasis on mechanistic aspects of the reactions.     

Electrochemical behavior of Al2O3/Al composite coated Al electrodes through surface mechanical alloying in alkaline media

The behavior of $A{l}_2{O}_3/Al$ composite coated Al electrodes fabricated by surface mechanical alloying ‘SMA’ was studied. The work was accomplished using Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques in alkaline media $2MKOH$ were done at room temperature. Results show hydroxyl ions accumulate on the surface due to Al deformation micro cavities filling with $A{l}_2{O}_3$ until full charge blockage reached. A barrier cover layer development causing an increase of both resistance and capacitance as it becomes more stable and thinner with exposure time increase. Migrating hydroxyl ion inside micro cavity changed its composition from Al₂O₃ to stable tetrahedral $Al{\left(OH\right)}_4^{?}$ aluminate ions. Therefore future benefits could be reached by developing such surfaces having charge accumulation that enables environmental interaction.     

Thermodynamics and Phase Transition of Topological Dilatonic Lifshitz-Like Black Holes

It is known that scalar-tensor gravity models can be studied in Einstein and Jordan frames. In this paper, a model of scalar-tensor gravity in Einstein's frame is considered to calculate the Lifshitz-like black hole solutions with different horizon topologies. Thermodynamic properties and first order van der Waals-like phase transition are studied, and it is found that the Lifshitz parameter affects the phase structure. In addition, thermal stability is investigated by using the behavior of heat capacity and various methods of geometrical thermodynamics.     

Prediction of Solubility Parameters Based on the Explicit Expression of Statistical Thermodynamics

A robust and efficient procedure is presented for calculating the solubility parameter. An analytical equation for internal pressure is proposed. Through a simple relation reported by Verdier and Andersen (fluid phase equilibrium 231: 125–137, 2005), one can easily find the solubility parameter via our analytical equation for the internal pressure. Also, the radial distribution function (RDF) of a Lennard–Jones LJ (12, 6) fluid, proposed by Xu and Hu (fluid phase equilibrium 30: 221–228, 1986), has been employed to calculate the internal pressure of normal alkanes from methane to decane. Their solubility parameters were evaluated according to the calculated values of the internal pressure. A comparison between the experimental and the estimated values demonstrated a very good agreement between them.     

Fundamentals and some applications of photoelectrocatalysis and effective factors on its efficiency: a review

Effluents of a large variety of industries usually contain important quantities of synthetic organic compounds. The discharge of these compounds in the environment causes considerable non-aesthetic pollution and serious health risk factors. Since conventional wastewater treatment plants cannot degrade the majority of these pollutants, powerful methods for the decontamination of dye wastewaters have received increasing attention over the past decade. In this work, fundamentals and main applications of photoelectrocatalysis as one of the most powerful and recent progresses of emerging photoassisted electrochemical treatments with UV irradiation are studied. The effect of various effective factors such as photoanode type, light source and its intensity, pH solution value, type and concentration of supporting electrolyte, type of cathode electrode, to be moving of photoanode or solution, thicknesses of semiconductor film on the electrode surface, and applied potential on the destruction of pollutants is described. Furthermore, various methods used for TiO₂ modification are mentioned. Also, application of photocatalysts except semiconductors is presented for photoelectrocatalytic aims. Finally, application of photoelectrocatalysis in determination of materials as a new method is discussed.