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61.
M. H. Hashmi Ahmad Iftikhar Ajmal Abdur Rashid Tehseen Qureshi 《Mikrochimica acta》1969,57(1):100-107
Summary Cupric chloride-triphenylphosphine complex gives red color witho-phenylenediamine having maximum absorption at 505–520 nm and 0.5g/ml as visual limit of identification. The reaction is specific foro-phenylenediamine and obeys Beer's law (1 to 10g/ml). This reaction provides the basis of a new method for the Spectrophotometric determination ofo-phenylenediamine ing quantities.Ruthenium trichloride-triphenylphosphine complex gives blue color withp-phenylenediamine having maximum absorption at 580 nm and 2g/ml as visual limit of identification. On the basis of this color reaction a Spectrophotometric method for the determination ofp-phenylenediamine in hair dyes is described. The recovery of the dye from commercial preparations is better than 97%. Other organic compounds do not interfere.
Zusammenfassung Kupfer(II)chlorid-triphenylphosphin reagiert mito-Phenylendiamin unter Rotfärbung mit maximaler Absorption bei 505 bis 520 nm und 0,5g/ml als Erfassungsgrenze. Die Reaktion ist für o-Phenylendiamin spezifisch und folgt dem Beerschen Gesetz zwischen 1 und 10g/ml. Sie dient als Grundlage für eine neue Methode der spektrophotometrischen Bestimmung von Mikrogrammengen o-Phenylendiamin.Rutheniumtrichlorid-triphenylphosphin reagiert mit p-Phenylendiamin unter Blaufärbung mit maximaler Absorption bei 580 nm und 2g/ml als Erfassungsgrenze. Auf dieser Grundlage läßt sich p-Phenylendiamin in Haarfärbemitteln bestimmen. In handelsüblichen Präparaten werden mehr als 97% des enthaltenen Farbstoffes gefunden. Andere Verbindungen stören nicht.相似文献
62.
Ahmed Abd El-Fattah Mohamad Nageeb Hassan Ahmad Rashad Mona Marei Sherif Kandil 《International Journal of Polymer Analysis and Characterization》2020,25(5):362-373
Abstract An injectable composite hydrogel composed of polyvinyl alcohol (PVA) and bioactive glass (BG) particles were synthesized by a physical crosslinking approach. The morphology, mechanical properties, and viscoelasticity of the PVA/BG composite hydrogel were characterized. Scanning electronic microscopy (SEM) showed uniform and homogeneous distribution of BG particles throughout the composite hydrogel. The incorporation of 2.5?wt% of BG particles in the composite hydrogel formulations, enhanced the static compressive strength and static elastic modulus by 325% and 150%, respectively. The storage molds (G′) was greater than the loss modules (G′′) at all the frequency range studied, which revealed a self-standing elastic composite hydrogel with a smooth injectability. The PVA/BG composite hydrogel was also implanted subcutaneously in the dorsal region of adult male rats. After 4?weeks of implantation, no inflammatory cells were seen within and around the implant, which indicated that the composite hydrogel was biocompatible. The properties of the synthesized injectable PVA/BG composite hydrogel demonstrate its capability toward bone regeneration. 相似文献
63.
Summary A method for semiquantitative determination of aromatic and,-unsaturated aldehydes such as salicylaldehyde, anisaldehyde, vanillin, veratraldehyde, piperonal, cinnamaldehyde, furfural andp-dimethylaminobenzaldehyde by making circular spots of their isonicotinoyl hydrazones on chromatoplates with circular thin-layer Chromatographic apparatus and their comparison with sensitivity standards has been described. The accuracy is ± 5% and the method is rapid, simple and economical.
Zusammenfassung Ein Verfahren zur semiquantitativen Bestimmung aromatischer und,-ungesättigter Aldehyde wie Salioylaldehyd, Anisaldehyd, Vanillin, Veratrumaldehyd, Piperonal, Zimtaldehyd, Furfural und p-Dimethylaminobenzaldehyd durch Dünnschicht-Ringchromatographie ihrer Isonikotinsäurehydrazone und Vergleich mit Standardchromatogrammen wurde beschrieben. Die Genauigkeit beträgt ±5%.相似文献
64.
Ahmad Banihashemi C. S. Marvel 《Journal of polymer science. Part A, Polymer chemistry》1977,15(11):2667-2672
Polymers made from 2,2′-diiododiphenyl-4,4′-dicarbonyl dichloride, diphenyl ether, and isophthaloyl chloride have been made and converted to the 2,2′-diphenylethynyl derivatives. Introduction of units of isophthaloyl chloride reduced the melting point of these polymers to about 200°C, and they could then be cured by heating. A good glass laminate was prepared and cured from one of the polymers. 相似文献
65.
Mathematical Programming - A Correction to this paper has been published: 10.1007/s10107-020-01587-x 相似文献
66.
Mathematical Programming - A clutter is k-wise intersecting if every k members have a common element, yet no element belongs to all members. We conjecture that, for some integer $$k\ge 4$$ , every... 相似文献
67.
Summary
Bis(cyclopentadienyl)titanium(IV) diisothiocyanate [(Cp)2-Ti(NCS)2] reacts with MCl2 (M = Cu, Pd or Pt), [CuCl(PPh3)3], [RuCl2(PPh3)3] and [RuCl2(DMSO)4] (DMSO = dimethylsulphoxide) giving solid compounds of stochiometry [(Cp)2Ti(-NCS)2MCl2] (M = Cu, Pd or Pt), [(Cp)2Ti(-NCS)2CuCl(PPh3)], [(Cp)2Ti(-NCS)2-RuCl(PPh3)2]Cl and [(Cp)2Ti(-NCS)2RuCl2(DMSO)2]. These products have been characterized by physicochemical and spectroscopic methods. 相似文献
68.
Ahmad Rouhollahi Mohammad Kazem Amini Mojtaba Shamsipur 《Journal of solution chemistry》1994,23(1):63-74
Proton NMR was used to study the complexation reaction between lead ion and 18-crown-6 in a number of binary acetonitrile-water mixtures. Formation constant for the resulting 11 complexes in different solvent mixtures was determined by computer fitting of the chemical shift-mole ratio data. There is an inverse relationship between the complex stability and amount of water in the mixed solvent. The dissociative kinetics of the complex was studied by proton line-shape analysis. The Arrhenius plots showed a distinct isokinetic temperature at about 25°C at which the decomplexation rate is more or less independent of the solvent composition. the complexation rate and the activation parameters E
a
, H and S, for the exchange have been determined and found to be strongly solvent dependent. There is actually a linear relationship between the mole fraction of acetonitrile in the mixed solvent and logarithm of the stability constant as well as activation parameters. 相似文献
69.
Lopez-Martens A Hannachi F Dossing T Schück C Collatz R Gueorguieva E Vieu C Leoni S Herskind B Khoo TL Lauritsen T Ahmad I Blumenthal DJ Carpenter MP Gassmann D Janssens RV Nisius D Korichi A Bourgeois C Astier A Ducroux L Le Coz Y Meyer M Redon N Sharpey-Schafer JF Wilson AN Korten W Bracco A Lucas R 《Physical review letters》1996,77(9):1707-1710