VOLUME 16, NO2, JUN 1994

THERMODYNAMICS OF ADSORPTION OF RHODAMINE-B AND NILE BLUE SULFATE ON ALUMINA FROM AQUEOUS-SOLUTIONS

Adsorption of the cationic dyes: Rhodamine B and Nile Blue Sulphate, from their aqueous solutions, on alumina was investigated. The adsorption of the dyes was found to decrease with the increase in temperature of the solutions. The adsorption isotherms obtained at different temperatures were found to obey the Langmuir isotherm equation. Free energy, entropy and enthalpy of the adsorption were calculated from the isotherms and the values, obtained for these thermodynamic parameters, were interpreted. The thermodynamic data indicate that the adsorption of these dye molecules on alumina is more favourable at high temperature.read more

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F MAHMOOD ,M SALEEM ,A HAMEED ,M AFZAL ,

SPECTROSCOPIC STUDIES OF THE DETERMINATION OF CHAIN GROWTH INTERMEDIATE IN THE FISCHER-TROPSCH SYNTHESIS REACTION ON THE BIMETALLIC SUPPORTED SYSTEM

The ruthenium-manganese bimetallic alloy system was prepared by co-impregnation method from the ionic solution of ruthenium chloride and manganese chloride dispersed on the high surface area aluminium oxide support and reduced to metallic form at 450 degrees C under hydrogen flow. The prepared sample was characterised using BET surface area measurement and atomic adsorption spectroscopy. The prepared sample was then subjected to carbon monoxide hydrogenation reaction in the continuous flow reactor. The sample was then taken out of the reactor and transferred to Secondary ion mass spectrometer, X-ray photo electron spectrometer and Infra red spectrometer for study. The study indicates the presence of CH2 group on the surface. On the basis of this intermediate a mechanism for the formation of higher hydrocarbons in the Fischer Tropsch Synthesis has been postulated. In this manuscript modern spectroscopic techniques have been used in determining the chain growth intermediate for the well known Fischer Tropsch Synthesis used for the production of hydrocarbon products in the Petrochemical Industry.read more

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S T HUSSAIN ,

EFFECT OF TEMPERATURE ON THE VISCOSITY OF DILUTE POLYELECTROLYTE SOLUTIONS

We report the effect of temperature on the viscosity of dilute polyelectrolyte solutions. It has been observed that the reduced viscosity increases with dilution, reaches to a maximum and then decreases in the limit of infinite dilution. Moreover, the maximum decreases and shifts towards higher polymer concentration with increase in temperature. Thermodynamic parameters of viscous flow (Delta G(v), Delta H-v, Delta S-v) have also been calculated and discussed.read more

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K AHAD ,N AHMAD ,A SAEED ,M S KHAN ,

SPECTROSCOPIC STUDIES OF THE COMPLEXES OF UREA WITH GROUP(II) METAL-HALIDES

The infra-red spectra, between 4000-400 cm(-1), and the Raman spectra, between 1700-950 cm(-1), of all the complexes of urea with group II metal halides are recorded to distinguish the mode of coordination of urea in these complexes. The e.s.r. spectra, at both (X) under bar- and Q-band of Mn(II) ions doped in these complexes are reported and the zero-field splitting parameters D and lambda (=E/D) are deduced. For anhydrous complexes, with 1:4 stoichiometery, the observed D and lambda values are consistent with trans-MO(4)X(2) chromophores. Very small values of D observed for the hydrated analogues suggest an MO6(2+) chromophore. For 1:6 complex of CaCl2, the value of D and lambda is exactly similar to that of Ca(urea)(4)Cl-2, suggesting similar structure. For all other complexes of 1:6 stoichiometery, the observed values are consistent with a coordination sphere of six oxygen atoms.read more

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I HUSSAIN ,M GOODGAME ,

PREPARATION AND ESR STUDY OF THE COMPLEXES OF AMINO-ACIDS WITH CALCIUM AND MAGNESIUM

The preparations are reported of the complexes of calcium and magnesium with amino acids; Glycine, beta-Alanine and L-Proline. The complexes have been characterized by elemental analyses. Esr spectra at both X- and Q-band are reported for manganese (II) ions doped in the lattices of these complexes, and the zero-field splitting parameters D and lambda(= E/D) are deduced. The D value observed for Ca(L-pro)(2)Cl-2 is consistent with a trans- CaO4Cl2 chromophore. Very small values of D observed for all the hydrated complexes suggest an MO6(2+) chromophore. Esr spectra of Mg[(Gly)(2)(H2O)(4)](NO3)(2) and Mg[(beta-Ala)(H2O)(4)]Cl-2, closely resemble that of previously reported zinc complex, Zn[(beta-Ala)(2)(H2O)(4)](NO3)(2), which contains octahedral structure with four water molecules and the beta-Alanine molecules occupying the trans-positions.read more

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M GOODGAME ,I HUSSAIN ,

BETA-CYCLODEXTRIN-ENHANCED FLUOROMETRY OF POLYAROMATIC DIALDEHYDE-DERIVATIVES AND ITS APPLICATION TO AMINES AND AMINO-ACIDS DETERMINATION

An investigation of naphthalene-2,3-dicarboxaldehyde (NDA) as a potential derivatising reagent for the fluorimetric determination of amines and amino acids in the presence of beta-cyclodextrin has been conducted. Enhanced fluorescence was observed in most cases. Experimental conditions, including pH of the medium, are optimised for the formation of the fluorescent NDA-derivatives. The fluorimetric determination of amines and amino acids by the beta-cyclodextrin - enhanced fluorimetry is reported along with an expected possible mechanism of these beta-cyclodextrin - included reactions.read more

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J N MILLER ,M AMINUDDIN ,

MICELLAR PHASE-TRANSFER CATALYSIS - A SUITABLE PROCEDURE TO DERIVATIZE CARBOXYLIC-ACIDS IN BIOLOGICAL MATRICES

The potential of micellar-phase transfer catalysis (MPTC) is shown by derivatization of various carboxylic acids with 9-bromomethylacridine (Br MAC). These carboxylic acids were monitored in the pre-column derivatization mode by fluorescence detection in a completely automated system. The application of the methodology to analysis of the biological sample is shown.read more

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A R SAMO ,G A QURESHI ,S A ARBANI ,M A CHIPPA ,M Y KHAHWER ,

EMULSIFIED SUBSTRATE IN FLOW SYSTEM - THE DETERMINATION OF LIPASE ACTIVITY

A fast flow system for the quantitative determination of lipase is described Crude lipase preparation from porcine pancreas is used. The substrate used is p-nitrophenyl laurate emulsion in polyvinylalcohol, p-nitrophenol is quantitated spectrophotometrically at 405 nm. The detection limit is 0.1 U ml(-1) and the sample throughput is 25 hr(-1). The relative standard deviation for 10 injections of 92.5 U ml(-1) was 1.5%.read more

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M MASOOM ,M YAQOOB ,M ANWAR ,

SYNTHESIS OF SOME NEW HETEROCYCLIC-COMPOUNDS FROM 3-CHLORO-4(INDOL-3-YL)PYRIDAZINE

The title compound was allowed to react with p-aminoacetophenone followed by condensation with benzaldehyde to give chalcone which is used in the preparation of new compounds containing the pyrazoline, isoxozoline, pyrimidone and pyrimidine thione moiety through its reaction with hydrazines, hydroxylamine hydrochloride, urea and thiourea. The product of p-aminoacetophenone when treated with bromine - acetic acid mixture gave the dibromo derivative which on reaction with thiourea gave the 2-aminothiazole derivative. The reaction of the title compound with sulfanilamide is also described.read more

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A RADWAN ,M KHAN ,M S A HALEM ,G H SAYED ,

SYNTHESIS, OF ORTHO-NITRO-N,N'-DIMETHYLBENZYLAMINE DERIVATIVES OF GROUP-I-(B) AND GROUP-II-(B) METALS

Derivatives of o-Nitro-N,N'-dimethylbenzylamine with group I (b) and II (b) metals were synthesised and characterized. The proposed formulae are based on the analytical data, chemical characteristics and spectroscopic evidence. The compounds are very stable, crystalline in nature and are obtained in high yield.read more

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M MUJAHID ,M Z IQBAL ,B A NASIR ,