VOLUME 15, NO4, DEC 1993

ADSORPTION OF URANIUM IN THE PRESENCE OF DIFFERENT CATIONS ON ACTIVATED-CHARCOAL

The adsorption of uranium in the presence of different cations namely Cd2+, Zn2+, La3+, Y3+, Sc3+ on activated charcoal from aqueous solution was studied at room temperature 23 +/- 0.2-degrees-C. Their effect on uranium adsorption has been correlated with the ionic potential, z/r of cations. It was observed that die cations with larger (z/r) reduced the uranium adsorption more than the cation with smallest (z/r) value. The Langmuir and Dubinin-Radushkevich (D-R) isotherm equations have been applied to the data and the values of parameters of these isotherm equations were evaluated. The mean energy of adsorption, E was also calculated from the adsorption energy constant, K' values determined from D-R isotherm equation. Wavelength dispersive X-ray fluorescence spectrometer was used for measuring uranium concentration in solutions.read more

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JAVED HANIF ,RIAZ QADEER ,

DETECTION OF SOURCE OF LOW-MASS PEAKS IN UF6 GASEOUS SAMPLE USING QUADRUPOLE MASS-SPECTROMETER

To determine the source of low mass peaks (0-45 amu) in gaseous Uranium Hexafluoride sample, a qualitative study was made using a Quadrupole Mass Spectrometer QMS 420 equipped with SEM and UHV facilities. The experimental findings indicates that some of these low molecular weights peaks are part of the sample and few fragments of hydrocarbons are added from oil of the diffusion pump. NO+, a product of the ion source is also detected. Many of these peaks also interfere with each other. An attempt is made to determine the origin of these interfering species in the spectrum.read more

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M ASHRAF ATTA ,AQIL KHAN ,S TAJAMMUL HUSSAIN ,

CARBON-MONOXIDE HYDROGEN TITRATION STUDIES ON RUMN ALUMINA-SUPPORTED BIMETALLIC SYSTEM FOR THE DETERMINATION OF METAL-SURFACE AREA

The CO/H-2 titration method was used to determine the metal surface area on Ru:Mn/Al2O3 supported system. This method was based on the assumption that CO is selectively adsorbed to form a monolayer on metal surface but is not adsorbed on the support surface and that all the adsorbed CO is hydrogenated to form CH4 selectively. The data indicate that Mn covers the surface of Ru and hence the no of active sites responsible for the production of CH4 is blocked by the addition of Mn. A continuous decrease in the dispersion of the active metal is discussed in terms of ensemble affect generated by the presence of Mn on the surface of Ru.read more

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S TAJAMMUL HUSSAIN ,

SPECTROPHOTOMETRIC STUDY OF COPPER(II), NICKEL(II) AND PALLADIUM(II) COMPLEXES OF BIS(BENZOYLACETONE)MESO-STILLBENEDIIMINE (BA2S) USING SOLVENT-EXTRACTION TECHNIQUE

The spectrophotometric study of copper(II), nickel(II) and palladium(II) complexes BA2S has been made here. The reagent and metal complexes were characterised by UV, VIS and IR methods [1] by copper, nickel and palladium from an aqueous solution into chloroform using reagent was optimised. The copper, nickel and palladium were extracted upto 94,64, and 97 percentages respectively.read more

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M Y KHUHAWAR ,Z TANWARI ,

MAGNETIC-SUSCEPTIBILITIES OF COPPER(II) COMPLEXES OF TETRADENTATE SCHIFF-BASES

The copper(II) complexes of the tetradentate Schiff bases show normal paramagnetic behaviour at room temperature. The values for effective magnetic moments, mueff, are in the range 1.34-2.41 B.M. which is normal for paramagnetic compounds having d9 configuration. Electronic reflectance spectra show a very broad band around 18000 cm-1 due to d-d transition.read more

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M A BABAR ,M Y KHUHAWAR ,R B BODZAR ,

STUDY OF ALUMINUM GALLIC ACID AND ALUMINUM GALLIC ACID METHYL-ESTER POTENTIOMETRICALLY USING COMPUTER-PROGRAM BEST

Potentiometric studies on complexation reaction between Al3+ (which has recently been implicated in neurological dysfunctions including Alzheimer's disease) and 3,4,5-Trihydroxybenzoic acid (gallic acid) and its methyl ester has been investigated. A computer program BEST was use to analyse the data. It is found that gallic acid form 1:1 complex up to pH 8.5 and a 1:2 complex between pH 8.5 and 11.0. Log beta1 and log beta2 values are 18.76 and 29.52, which are higher than those of Fe3+ complex of the same ligand. The methyl ester of gallic acid forms 1:1, 1:2 as well as 1.3 complexes with log beta1 log beta2 and log beta3 values of 23.8, 33.83 and 39.63 respectively. Implications of these formation constants for polyphenol complexes of Al3+ upon Al absorption and resulting toxicity are discussed.read more

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Z T MAQSOOD ,SHABANA AMIN ,S A KAZMI ,

THE CYCLIZATION OF (Z) AND (E)-3-ETHOXYCARBOYL-4(3'-CHLORO-6'-METHYL-PHENYL)-BUT-3-ENOIC ACID AND SYNTHESIS OF POLYSUBSTITUTED NAPHTHOIC ACID

The condensation of 5-chloro-2-methylacetophenone with diethyl succinate in the presence of potassium t-butoxide gave a mixture of (Z)- and (E)-3-ethoxy-carbonyl-4-(3'-chloro-6'-methylphenyl) but-3-enoic acid. Cyclisation of (E)- and (Z)-half-esters afforded the naphthalene derivative and oxo-indenyl acid via the anhydride formation, respectively. The reaction of (E)-anhydride with aromatic hydrocarbons, amines and anhydrous aluminium chloride in acetylene tetrachloride was also investigated. The IR, 1N-NMR and mass spectra of the products were discussed.read more

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M R MAHMOOD ,

SYNTHETIC STUDIES IN THE FIELD OF OXYAJMALANE ALKALOIDS

Some new oxidation products of ajmalane alkaloids have been synthesized by their reaction with hydrogen peroxide and are characterized by spectroscopic methods.read more

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SYED NAJAM UL HUSSAIN ,ZAHEER AHMAD ,MOHAMMAD ATA ULLAH KHAN ,

REACTION OF ETHYL ARYLIDENECYANOACETATES WITH HYDRAZINE DERIVATIVES

Several new polysubstituted pyrimidine and pyrazole derivative were synthesized via reaction of ethyl arylidenecyanoacetates with different hydrazine derivatives.read more

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LAILA I IBRAHIM ,

AN APPROACH TO THE A RING OF VITAMIN-D VIA SEQUENTIAL CARBOMETALATION ANION CAPTURE

An intramolecular palladium catalyzed carbometalation followed by anion capture achieves construction of model comprising the A ring of vitamin D. The synthesis of appropriate bromoenyne (10) for successful implementation of strategy is also described.read more

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M BAKAVOLI ,M M HERAVI ,