Presence Of Phosphotungstic Acid Research Articles

Partitioning of Americium(III) in Polyethyleneglycol based Aqueous Biphasic Systems in Presence of Phosphotungstic Acid

Partitioning of Americium(III) in Polyethyleneglycol based Aqueous Biphasic Systems in Presence of Phosphotungstic Acid

Chemical preparation of polyaniline containing heteropolyanions

Polyaniline containing anions of phosphotungstic acid has been prepared in a one-step reaction involving oxidation of aniline with ammonium persulfate in the presence of phosphotungstic acid. The presence of heteropolyanions (so-called structural Keggin units) in the polymer has been confirmed by elemental analysis and IR spectroscopy which showed the existence of the five strongest modes of the inserted anion in addition to the features characteristic of the protonated polyaniline chain. The anions enter the polymer matrix in their highest oxidation state (all tungstens at +6 oxidation level) since EPR spectra show only one single line characteristic of the polyaniline radical with no lines attributable to the reduced form of tungsten. The obtained product seems to be an excellent candidate for application in heterogeneous catalysis involving acid-base processes because, despite the fact that it deteriorates electrically at elevated temperatures, it retains catalytically active Keggin units.

ChemInform Abstract: Aerobic and Anaerobic Photooxidation of p‐Xylene in the Presence of Phosphotungstic Acid and Its Tetrabutylammonium Salt

ChemInformVolume 21, Issue 4 Preparative Organic Chemistry ChemInform Abstract: Aerobic and Anaerobic Photooxidation of p-Xylene in the Presence of Phosphotungstic Acid and Its Tetrabutylammonium Salt D. ATTANASIO, D. ATTANASIO Ist. Teor. Strutt. Elettron. Comportamento Spettrochim. Composti Coord., CNR, Roma, ItalySearch for more papers by this authorL. SUBER, L. SUBER Ist. Teor. Strutt. Elettron. Comportamento Spettrochim. Composti Coord., CNR, Roma, ItalySearch for more papers by this author D. ATTANASIO, D. ATTANASIO Ist. Teor. Strutt. Elettron. Comportamento Spettrochim. Composti Coord., CNR, Roma, ItalySearch for more papers by this authorL. SUBER, L. SUBER Ist. Teor. Strutt. Elettron. Comportamento Spettrochim. Composti Coord., CNR, Roma, ItalySearch for more papers by this author First published: January 23, 1990 https://doi.org/10.1002/chin.199004050Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume21, Issue4January 23, 1990 RelatedInformation

Aerobic and anaerobic photooxidation of p-xylene in the presence of phosphotungstic acid and its tetrabutylammonium salt

Aerobic and anaerobic photooxidation of p-xylene in the presence of phosphotungstic acid and its tetrabutylammonium salt

Ring formation of perfringolysin o as revealed by negative stain electron microscopy

Perfringolysin O revealed ring- and arc-shaped structures in the absence of cholesterol by negative staining electron microscopy, while before activation with cysteine it showed indistinct arcs and irregularly curved sticks but no rings. These structures were observed only at high concentrations (more than 17 000 hemolytic units per ml) and seemed to be particle associates with 20–28 particles (about 4 nm per particle) linked in a circle. The toxin produced an inactive and high molecular weight complex in the presence of phosphotungstic acid, which was isolated by Sephadex gel filtration. These findings suggest that the rings are the toxin-phosphotungstic acid complexes produced during specimen preparation on a grid in vacuo. The toxin lost the properties necessary for ring formation though moderate modification with glutaraldehyde, showing spindle- and egg-shaped particles of about 4 nm in minor and 5 nm in major axis by negative staining. These facts suggest that the aldehyde modifies the binding sites for phosphotungstic acid, which probably are the basic groups of the toxin molecules. In the presence of cholesterol, even at a low concentration, the toxin revealed rings and arcs by negative staining and also by carbon shadowing electron microscopy, although the toxin itself did not show any characteristic structure without phosphotungstic acid. These observations suggest that the rings are the toxin-cholesterol complexes themselves. The toxin-phosphotungstic acid complexes seemed to have a structure of a single layer of particle associates, while that of the toxin-cholesterol complexes may consist of double or triple layers of the associates because its border was thicker and more distinct.