ABSTRACT The concentration of six heavy metals and six of sixteen (16) US EPA priority polycyclic aromatic hydrocarbons (PAHs) in water, fish and sediment samples of the confluence of rivers Niger and Benue were investigated in triplicates using atomic absorption spectrophotometer (AAS) for the heavy metals determination and gas chromatography coupled with mass spectrometer detector for the PAHs after acid digestion of the samples for heavy metals,liquid-liquid and solid-liquid extracti...
ABSTRACT Magnetically recoverable Pd/Fe3O4-catalyzed Hiyama cross-coupling reactions of 6-Bromo-5H-benzo[a]phenothiazin-5-one, 6-Bromo-5H-naphtho[2,1-b]pyrido[2,3-e][1,4]oxazin-5-one and 11-Amino-6-bromo-9-thio-5H-naphtho[2,1-b]pyrimido[5,4-e][1,4]oxazin-5-one (as intermediates) with 2-(Dimethylsilyl)pyridine and Dimethyl(2-thienyl)silanol were investigated. The intermediates were prepared by the reactions of 2-Aminothiophenol, 2-Aminopyridin-3-ol and 4,5-Diamino-6-hydroxylpyrimidin-2-t...
ABSTRACT The roots of Dennettia tripetala and Milicia excelsa were analyzed for the presence of phytochemicals. Five different solvents, which include methanol, ethanol, ethyl acetate, butanol and water, were used for the extraction of the phytochemicals.The root of Dennettia tripetala contained alkaloids, terpenoids, flavonoids, saponins, phenols, steroids and glycosides in varying degrees of abundance in the different solvents with tannins not detected in all the solvents. Milicia excelsa...
ABSTRACT Tandem amidation catalyzed synthesis of linear diazaphenoxazine carboxamide derivatives is reported. This was achieved by the reaction of 2-amino-3-hydroxypyridine and 2,3,5-trichloropyridine in aqueous basic medium which gave 3-chloro-1,9-diazaphenoxazine as white solid crystals. 3-Chloro-1,9-diazaphenoxazine was then subjected to Buchwald-Hartwig amidation coupling reaction with various amides namely formamide, phthalamide, 4- nitrobenzamide, benzamide and acetamide via water prom...
ABSTRACT The syntheses of benzothiazinophenothiazine derivatives from simple heterocyclic compounds as precursors is described. Condensation of 2-aminothiophenol with 2,3-dichloro-1,4-naphthoquinone in an alkaline medium furnished a good yield of the intermediate, 6-chloro-5H-benzo[a]phenothiazin-5- one. Further condensation of the intermediate with 2,4-diamino-6-hydroxypyrimidine-5-thiol obtained by alkaline hydrolysis of 2,4-diamino-6-hydroxy-5-thiacyanatopyrimidine gave the benzothiazinop...
ABSTRACT The study investigated the levels of organochlorine pesticide residues in both cocoa beans and soils of cocoa plantations in selected farms in Ondo State. Soil samples and cocoa pods were collected from four major farms in the State. The pesticide residues were extracted, cleaned up and analysed using Gas Chromatography-Electron Capture Detector (GC-ECD). In the analysed cocoa samples, the ranges of the mean concentrations of the organochlorine pesticides were: α-HCH (ND-0.094 mg/k...
ABSTRACT Heavy metal concentrations and degradation efficiency of total petroleum hydrocarbons (TPHs) on environment in Ibeno Local Government Area, Akwa Ibom State, Nigeria was investigated. Experimental design method was adopted for this study. Fifteen composite samples each of soil, leaves of Telfairia occidentalis, sediment and water were collected in December 2012 and June 2013. The sediment and water samples were collected using corer and clean plastic bottles respectively. Soil and se...
Table of Contents Certification . . . Dedication r . . . Acknowledgement r . Abstract . . . . . . L i s t of Figures . . List of Tables .. . Table of Contents .. Introduction Importance of t h e River . . Niger Possible Sources of P u l l u t i o n Xeed for Study . . Objective . . . . L i t e r a t u r R~ ev iew Experiment a1 Study Area Sampling Poi-nts Sampling . . Analysis .. Temperature Conductivity pH .. 0. Colour . .
ABSTRACT The Schiff base ligand, 2-[(E)-[{3--[(2-hydroxybenzylidene)amino]phenyl}imino)methyl]phenol was synthesized by condensing 1,3-diaminobenzene and 2-hydroxybenzaldehyde in absolute ethanol. Its Cr(III) and Cr(VI) complexes were equally synthesized. The ligand was characterized via UV, IR and NMR spectroscopy, whereas the complexes were characterized based on UV and IR spectroscopy and conductivity values. Stoichiometric studies indicated 1:1 metal to ligand ratio for both complexes. C...
ABSTRACT Theconcentrations of lead, nickel, silver, zinc, chromium, copper, vanadium, cobalt, and cadmium were determined in plastic housing of waste television sets produced in some years of 1980’s, 1990’s and 2000’s, and in plastics of waste mobile phones produced in some years of 1990’s and 2000’s, the samples were collected mainly from mobile phone and television repairers at railway in Ogbete main market, Enugu in Enugu state, and the famous computer village inIkeja, Lagos Sta...
ABSTRACT The potentials of Adansonia digitata root (ADRP) and stem powders (ADSP) and the stem activated carbon (ADSAC) for adsorption of Pb2+, Cd2+, Cu2+ and Co2+ from aqueous solutions were investigated. The activated carbon was prepared via chemical activation using ZnCl2 as the activating agent. Physico-chemical analysis of the adsorbents (ADRP, ADSP and ADSAC) showed the moisture contents (< 20 %), volatile matter (9.2 - 11.2 %), ash content showed < 5.0 %, fixed carbon (68 - 81.0 %), p...
ABSTRACT Palladium-catalysed Suziki-Miyaura cross-coupling (SMC) reactions of 6-chloro-5H benzo[a]phenothiazin-5-one, 11-amino-6-chloro-9-thio-5H-naphtho[2,1-b]pyrimido[5,4-e][1,4] oxazin-5-one and 6-chloro-5H-naphtho[2,1-b]pyrido[2,3-e][1,4]oxazin-5-one with phenylboronic acid and 3-nitophenylboronic acid were thoroughly investigated. The above intermediates were prepared by the reactions of 2-aminothiophenol, 4,5-diamino-6-hydroxylpyrimidine-2-thiol and 2- aminpyridin-3-ol respectively wi...
ABSTRACT Palladium-catalysed Suziki-Miyaura cross-coupling (SMC) reactions of 6-chloro-5H benzo[a]phenothiazin-5-one, 11-amino-6-chloro-9-thio-5H-naphtho[2,1-b]pyrimido[5,4-e][1,4] oxazin-5-one and 6-chloro-5H-naphtho[2,1-b]pyrido[2,3-e][1,4]oxazin-5-one with phenylboronic acid and 3-nitophenylboronic acid were thoroughly investigated. The above intermediates were prepared by the reactions of 2-aminothiophenol, 4,5-diamino-6-hydroxylpyrimidine-2-thiol and 2- aminpyridin-3-ol respectively wi...
ABSTRACT The removal of Pb(II) ions from aqueous model solution using zeolite has been investigated under different operational parameters like heavy metal ion concentration, adsorbent amount and particle size. The zeolite used was synthesized and characterized using SEM and XRD analysis. The equilibrium adsorption capacity of zeolite used for lead removal were measured and the experimental data analyzed by means of Freundlich and Langmuir isotherm models. The adsorption efficiency of Zeolit...
ABSTRACT 3,5-Bis[(2-hydroxy-benzylidene)-amino]-benzoic acid (H2B) and its cobalt(II) and nickel(II) complexes were synthesized and characterized via: electronic, IR, 1H NMR and 13C NMR. Job’s continuous variation method was used to determine the mole ratio for both metal complexes. Solvent extraction studies were carried out on H2B in 5% DMF with its cobalt(II) and nickel(II) complexes using CHCl3 as organic solvent; with variable condition effects of equilibrium time, buffer pH, mineral ...