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31.
A spectrophotometric method for determination of a microgram quantity of cerium with N-p-tolyl-p-chlorobenzohydroxamic acid is described. The orange-red-colored complex is extracted from chloroform at pH 9 which absorbs between 460 and 465 nm. Beer's law is obeyed at this wavelength. A clean-cut separation from many commonly occurring metal ions is easily accomplished. The system obeys Beer's law within the range of 0.5–28 ppm of cerium(IV). The molar absorptivity of cerium-N-p-tolyl-p-chlorobenzohydroxamic acid complex is 4.5 × 103 liters mol?1 cm?1. 相似文献
32.
33.
The enantiomeric resolution of (+/-)-ibuprofen into its enantiomers was achieved by TLC on silica gel plate using optically pure (-)-brucine as a chiral selector and acetonitrile-methanol (5:1, v/v) as the solvent system. Spots were located in an iodine chamber. The detection limit was 4.9 microg. The effect of concentration of the chiral selector, temperature and pH on resolution has been studied. 相似文献
34.
Santosh K. Upadhyay Mahesh C. Agrawal 《Monatshefte für Chemie / Chemical Monthly》1979,110(2):413-418
Osmium(VIII) catalysed oxidation of lysine by ferricyanide in excess ferrocyanide shows a complex kinetics. The order in lysine falls, from 1 to 0 while that in ferricyanide increases from 0 to 2 with large increase in lysine concentration. The rates were directly proportional to [Os(VIII)] and {Const.+[Fe(CN)
6
4
]}. A suitable mechanism is proposed and discussed.
Oxidation von lysin mittels ferricyanid in der gegenwart von osmium(VIII)
Zusammenfassung Die von Os(VIII) katalysierte Oxidation von Lysin mit Ferricyanid in überschüssigem Ferrocyanid zeigt eine komplexe Kinetik. Bei starker Steigerung der Lysinkonzentration fällt die Ordnung bezüglich Lysin von 1 auf 0, während bezüglich Ferricyanid eine Erhöhung, von 0 auf 2 festzustellen ist. Die Geschwindigkeitskonstanten waren direkt proportional zu [Os(VII)] und {Const.+[Fe(CN) 6 4 ]}. Es wird ein möglicher Mechanismus vorgeschlagen und diskutiert.相似文献
35.
Noor-ul H. Khan Santosh Agrawal Rukhsana I. Kureshy Sayed H.R. Abdi Surendra Singh Raksh V. Jasra 《Journal of organometallic chemistry》2007,692(20):4361-4366
An efficient method for the addition of trimethylsilyl cyanide (TMSCN) to various aldehydes and ketones has been described using Fe(Cp)2PF6 (2.5 mol%) as a catalyst under solvent free condition. Excellent yields of trimethylsilylether of cyanohydrin up to (94%) was achieved within 10 min. 相似文献
36.
Salicylidene-o-aminobenzothiol and its 5-chloro and 5-bromo derivatives, dibasic tridentate Schiff bases, dervied from the condensation of o-aminothiol and Salicylaldehyde, 5-chloro salicylaldehyde and 5-bromo salicylaldehyde, were used for coordination with Zr(IV), Th(IV) and UO2(VI) metal inos. The I:I (metal-ligand) stoichiometry of these complexes is shown by elemental analysis and conductometric titrations. Molecular structure of these complexes are proved by Infra-red spectroscopy and thermogravimetric analysis. Magnetic susceptibility measurements of Zr(IV), Th(IV) and UO2(VI) complexes show their diamagnetic and octahedral geometry. Results show that all the complexes have solvent molecules in coordination with metal ion. 相似文献
37.
38.
A new crown hydroxamic acid, 5,14-N,N'-hydroxyphenyl-4,15-dioxo-1,5,14,18-tetraaza hexacosane (NHDTAHA) for the extraction and spectrophotometric determination of lanthanum(III) is described. Lanthanum(III) forms a yellow coloured complex with NHDTAHA, which is extracted with chloroform, having molar absorptivity 7.7 x 10(3) 1 mol(-1) per cm at 372 nm. The system obeys Beer's law in the range 1.2-20 ppm of lanthanum. The extract is directly aspirated for ICP-AES measurements, the limits for estimation are 5-140 ppb of lanthanum. Lanthanum has been determined in monazite sand and standard samples. 相似文献
39.
K. S. Sharma K. Bhushan 《Journal of photochemistry and photobiology. A, Chemistry》1987,40(2-3):371-380
The pH dependence of the absorption and fluorescence spectra of Schiff's bases derived from 2-amino-4-phenylthiazole and aniline with substitued 2-hydroxybenzaldehydes was investigated. The pKa values of the Schiff's bases associated with the ground state equilibria were determined spectrophotometrically. The excited state pKa values were also estimated. Their Stokes shifts were also calculated. 相似文献
40.
Anuradha Mishra Malvika Bajpai Sunita Pal Monika Agrawal Sushant Pandey 《Colloid and polymer science》2006,285(2):161-168
The application of Tamarindus
indica seed mucilage (Tam), a food grade polysaccharide, and its acrylamide grafted copolymer as flocculants was assessed for the first time for removal of various types of dyes from model textile wastewater containing azo, basic, and reactive dyes. Acrylamide grafted T. indica mucilage (Tam-g-PAM) was obtained by ceric ion initiated polymerization technique. A series of contact time experiments were conducted to assess the system variables such as concentrations of mucilage and dyes and pH. These flocculants reduce the dye concentration by flocculation and settling. The grafted copolymer, Tam-g-PAM showed better results for dye removal. The optimal flocculant concentration, which was required to effect flocculation, was independent of dye concentration within the range examined. Both the flocculants performed better for removal of azo dyes than for reactive and basic dyes. 相似文献