Experimental Investigations on the Thermal Diffusion Characteristics and Photoluminescence in Multiphase Micro Fluids Containing ZnO Micro Tubes and Fluorescein Dye

Optics and Spectroscopy - Scattering of light by disordered structures is normally detrimental to their applicability in many optoelectronic devices. However, some micro and nanostructures are...     

Mixed-ligand chelate extraction of neodymium(III) with thenoyltrifluoroacetone and various sulphoxides

Mixed-ligand chelate extraction of Nd(III) into benzene with mixtures of thenoyltrifluoroacetone (HTTA) and bis-2-ethylhexyl sulphoxide (B2EHSO) or di-n-octyl sulphoxide (DOSO) or diphenyl sulphoxide (DPhSO) or trioctylphosphine oxide (TOPO) from thiocyanate solutions has been studied. A very high synergistic enhancement of the order 10(3) has been observed in these systems. Thus this mixed-ligand chelate system may be useful in the extraction and separation of Nd(III) from other metal ions. The mechanism of extraction can be explained by a simple chemically based model presented in this paper.     

Synthesis and Bioassay of Ethyl-2- (2-((Diethoxyphosphoryl) (Aryl) Methylamino)Thiazol-4-Yl)-2-(Methoxyimino)Acetates

Abstract

A simple, efficient, and environmentally benign methodology has been accomplished for the synthesis of α-aminophosphonates by one-pot three-component reaction of ethyl-2-amino-α-(methoxy-imino)-4-thiazoleacetate, aldehydes, and diethylphosphite by using Amberlyst-15 as catalyst at room temperature under solvent-free conditions. Their chemical structures were characterized by infrared (IR), NMR (¹H, ¹³C & ³¹P), mass spectral, and elemental analysis. All the title compounds were screened for radical-scavenging activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH), nitic oxide (NO), and hydrogen peroxide (H₂O₂) methods.

Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional text and figures.     

Molybdenum Catalyzed Protective Tetrahydropyranylation of Alcohols and Phenols

Molybdenyl(VI) acetylacetonate is an effective catalyst for the protective tetrahydropyranylation of alcohols and phenols.     

Lignite fired fly ash modified by chemical treatment for adsorption of zinc from aqueous solution

The purpose of the study described in this paper was to compare removal of Zn(II) from aqueous solutions by use of two adsorbents—alkali-modified fly ash (FAN) and alkali and dye-modified fly ash (FAN-MO). The effects of four conditions (solution pH, contact time, initial metal ion concentration, and dose of adsorbent) on removal of Zn(II) at 27 ± 5 °C were studied in batch mode. Adsorption of Zn(II) was greater at pH 4.0 for FAN (76.49 %) and at pH 5.0 for FAN-MO (24.72 %). Maximum adsorption of Zn(II) by FAN and FAN-MO was achieved after 50 min. The linear forms of the Langmuir, Freundlich, Tempkin, D–R, Harkin–Jura, and Frenkel–Halsey isotherms were used for experiments with different concentrations of the metals. Adsorption of Zn(II) ions satisfied the Langmuir isotherm model only. The adsorption capacity of both adsorbents was also investigated by column studies. Adsorption of Zn(II) ions on FAN in column studies (45.33 %) was lower than in batch mode studies. For FAN-MO, adsorption was 37.88 % in column studies, again lower than in batch mode studies. Fly ash modified by alkali had a higher adsorption capacity for Zn(II) ions than fly ash modified by alkali followed by addition of dye.     

Synthesis and in vitro antimicrobial studies of thiodihydropyrimidine derivatives

In the present study, a series of thiodihydropyrimidine derivatives were synthesized from different substituted aromatic aldehydes, ethyl acetoacetate, and urea/thiourea using a bimetallic TUD-1 catalyst. The structures of all the synthesized compounds were characterized by melting point determination, thin layer chromatography (TLC), infrared (IR), ¹HNMR, and ¹³C-NMR values. All the synthesized compounds were screened for their antimicrobial activities against two gram positive bacteria, two-gram negative bacteria, and two fungal strains.     

A quick and regioselective access of spirooxindole-oxazoline by reaction of isatin and isocyanoacetate “on water”

A greener, rapid and regioselective “on water” synthesis of spirooxindole-oxazoline by the reaction of isatin and isocyanoacetate at room temperature is described. The developed protocol has the advantage of being atom-economical, eco-friendly, and benign reaction conditions. Broader substrate scope, experimentally simple procedures, and easy purification of products with high yield further make this method attractive. The synthesized compounds have been fully characterized with spectral analysis.     

Mechanism and linear free energy relationships in the kinetics of formation of bicyclo[3.3.1]nonane derivatives from 1,3,5‐trinitrobenzene,phenyl‐substituted 1‐benzyl‐1‐(ethoxycarbonyl)‐2‐propanones,and triethylamine

The kinetics and mechanism of cyclization of the anionic sigma complex obtained from the reaction of 1,3,5‐trinitrobenzene (TNB) and 1‐benzyl‐1‐(ethoxycarbonyl)‐2‐propanone (BEP) in the presence of triethylamine (NEt₃) have been studied in CH₃CN–CH₃OH (50% v/v). The order of the reaction has been found to be zero in TNB and BEP, unity in NEt₃, and negative and nonintegral in triethylammonium chloride. The rate has been observed to increase slightly with an increase in the concentration of the added salt (tetraethylammonium chloride). The rate constants for the formation of bicyclic adducts from phenyl‐substituted BEP and TNB in the presence of triethylamine have been correlated with σ values. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 43: 467–473, 2011     

Investigations on Pd:SnO2/porous silicon structures for sensing LPG and NO2 gas

P-type porous silicon (PS) structure has been prepared by anodic electrochemical etching process under optimized conditions. Photoluminescence studies of the PS structure show emission at longer wavelengths (red) for the excitation at 365 nm. Scanning electron microscope investigations of the PS surface confirm the formation of uniform porous structure, and the pore diameter have been estimated as 25 μm. Pd:SnO₂/PS/p-Si heterojunction with top gold ohmic contact developed by conventional methods has been used as the sensor device. Sensing properties of the device towards liquefied petroleum gas (LPG) and NO₂ gas have been investigated in an indigenously developed sensor test rig. The response and recovery characteristics of the sensor device at different operating temperatures show short response time for LPG. From the studies, maximum sensitivity and optimum operating temperature of the device towards LPG and NO₂ gas sensing has been estimated as 69% at 180 °C and 52% at 220 °C, respectively. The developed sensor device shows a short response time of 25 and 57 s for sensing LPG and NO₂ gases, respectively. Paper presented at the Third International Conference on Ionic Devices (ICID 2006), Chennai, Tamilnadu, India, Dec. 7–9, 2006.     

MoO2(acac)2-A Mild and Efficient Catalyst for the Deprotection of Acetals

Molybdenyl(VI) acetylacetonate is an effective catalyst for the deprotection of acetals into the corresponding aldehydes and ketones, in good yields.