Home About us Contact
|
Home About us Contact | ||
|
|
||
Tungstophosphoric Acid (tungstophosphoric + acid)
Selected AbstractsOn Water: An Efficient Knoevenagel Condensation Using 12-Tungstophosphoric Acid as a Reusable Green Catalyst.CHEMINFORM, Issue 10 2007Hossien A. Oskooie Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Effective and Regioselective Iodination of Arenes Using Iron(III) Nitrate in the Presence of Tungstophosphoric Acid.CHEMINFORM, Issue 25 2006Mohammad Jafarzadeh Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Fabrication and Application of a Novel Modified Electrode Based on Multiwalled Nanotubes/Cerium(III) 12-Tungstophosphoric Acid NanocompositeELECTROANALYSIS, Issue 11 2008Bin Fang Abstract A novel multiwalled nanotubes (MWNTs)/Cerium(III) 12 - tungstophosphoric acid (CePW) nanocomposite film glassy carbon electrode was prepared in this paper. Electrochemical behaviors of the CePW/MWNTs modified electrode were investigated by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). This modified electrode brought new capabilities for electrochemical devices by combining the advantages of carbon nanotubes, rare-earth, and heteropoly-acids. The results demonstrated that the CePW/MWNTs modified electrode exhibited enhanced electrocatalytic behavior and good stability for the detection of guanine and adenine in 0.1,M PBS (pH,7.0). The experimental parameters were optimized and a direct electrochemical method for the simultaneous determination of guanine and adenine was proposed. The detection limit (S/N=3) for guanine and adenine was 2.0×10,8,M and 3.0×10,8,M, respectively. Further, the acid-denatured calf thymus DNA was also detected and the result was satisfied. [source] Bulk and supported tungstophosphoric acid as friendly, efficient, recyclable catalysts for the synthesis of bis-indolylmethanes under solvent-free conditionsHETEROATOM CHEMISTRY, Issue 6 2009Hamid Aliyan The treatment of indole with structurally diverse aldehydes in the presence of catalytic amount of inorganic-supported polyoxometalates, heterogeneous, reusable and efficient catalysts at room temperature gave the corresponding bis-indolylmethanes in excellent yields and shorter reaction times under solvent-free conditions. The catalyst can be reused for several times, but it will be less active. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:325,331, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20554 [source] Facile route for the synthesis of benzothiazoles and benzimidazoles in the presence of tungstophosphoric acid impregnated zirconium phosphate under solvent-free conditionsHETEROATOM CHEMISTRY, Issue 4 2009Hamid Aliyan Rapid and efficient condensation reactions of o -phenylenediamine and o -aminothiophenol with various aldehydes were carried out using tungstophosphoric acid impregnated zirconium phosphate in solvent-free conditions to afford the corresponding 2-substituted arylbenzimidazole and arylbenzothiazole derivatives in good to excellent yields. This procedure constitutes a simple and practical green synthetic method for 2-arylbenzimidazoles and 2-arylbenzothiazoles and their structural analogs. Furthermore, the catalyst can be reused for several times but it will be less active. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:202,207, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20534 [source] Determination of propafenone hydrochloride by flow-injection analysis coupled with resonance light scattering detectionLUMINESCENCE: THE JOURNAL OF BIOLOGICAL AND CHEMICAL LUMINESCENCE, Issue 2 2009Xiaoli Hu Abstract A simple, sensitive and rapid flow injection analysis (FIA) method with resonance light scattering (RLS) was described for the determination of propafenone (PPF). The method was based on the ion-association reaction of 12-tungstophosphoric acid (TP) with propafenone. In pH 1.0 acidic medium, TP reacted with PPF to form an ion-associate complex, which resulted in a significant enhancement of RLS intensity. The maximum scattering peak was located at 340 nm, the RLS intensity was proportional to the concentration of PPF in the range 0.003,9.0 µg/mL, and the detection limit (3,) of 1.0 ng/mL was obtained at a sampling rate of 60 samples/h. The feasible reaction conditions and FIA parameters for the system were optimized. The method proposed in this paper shows satisfactory reproducibility with a relative standard deviation (RSD) of 2.1% for 10 successive determinations of 2.0 µg/mL PPF. The present method had been successfully applied to the determination of PPF in serum samples and pharmaceutical samples. The results obtained were in agreement with the method used in the Chinese Pharmacopoeia. Copyright © 2008 John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||