Applied Chemistry

The inhibition of the corrosion of mild steel in 0.1 M HCl solution by Pyridine from 303 K to 333 K at concentrations of 5 x 10-4 M, 1 x 10-4 M, 5 x 10-5, 2 x 10-5 M and 1 x 10-5 M was studied using gravimetric technique. The maximum inhibition efficiency 70 % at 5 x 10-4 M for 333 K was observed. The compound acted as corrosion inhibitors in 0.1 M HCl solution through adsorption on the mild steel surface. The maximum heat of adsorption (Q) was 1.0297 KJ/mol whereas the average kinetic energy (Ea) was 20.0 KJ/mol. The weight loss data treated kinetically gave a first order type of mechanism. The results elucidated the effects of inhibitor concentration, temperature, d? – P? interaction between the metal surface, the heteroatom of the inhibitor, and the electron charge densities on the heteroatoms of the Pyridine molecule. The adsorption of the inhibitor on the metal surface obeyed Temkin adsorption isotherm. Quantum chemical calculations using Hartree-fock density functional theory by Hamiltonian method was employed with PM3 (NDDO) basic set of minimal valence basis as STO3G Program.

Linear model of cadmium content of soil samples in five commercial motor parks in some cities in South-eastern Nigeria were studied using analysis of variance and least significant difference test. The results showed that the mean values of three out of the five samples investigated and modeled were statistically significant at 95% probability level. Three of these five samples when compared with the cadmium permissible limits of 0.01 mg/kg were statistically significant at 95% probability level using the calculated least significant difference of 0.112 mg/kg. From the results of the analyses of the study, the Cadmium content in these choice locations were greater than the permissible limit of 0.01 mg/kg for Cadmium level in the environment.

The spectroscopic characteristics (IR) and the thermal properties (TGA, DTG and DTA) of the solid complexes obtained by the reaction of 2-hydroxyphenylhydrazoacetoacetanilide (2-HPHAAA) with Uranyl(II), and Thorium (IV) are reported and discussed.

: The equilibrium constants for metal complex formation have been employed from long as an effective measure and parameter of the affinity of a ligand for a metal ion in solution. PHmetry is one of the most convenient and successful technique employed for metal complex equilibrium measurements. pHmetric measurement of hydrogen ion concentration may be employed when the degree of complex formation is sensitive to the hydrogen ion concentration thus the degree of complex formation undergoes increase/ decrease with change in pH. In the present work, we investigate the stability constants of Paracetamol complexes with Co2+, Zn2+ and Cd2+pHmetrically using pH metric technique at three temperatures (25 ±0.1, 30 ±0.1 and 35± 0.10 C) and at an ionic strength of 0.1 mol L-1 (KNO3). The method of Calvin and Bjerrum as adopted by Irving and Rossotti has been employed to determine log K1 values. The thermodynamic parameters ?G, ?H and ?S are calculated. System tend to progress in the direction of increasing entropy as entropy is a measure of a system’s tendency towards spontaneous change. KEYWORDS: pH metry, Stability constant, Thermodynamic parameters, Entropy

In this work we reported the status of one of Ethiopia’s Great Rift Valley Lakes; “The ever expanding Lake known as Beseka” in respect to water quality parameters. A composite sample was prepared by combining equal volumes of water samples taken from five Sampling sites. Five physical parameters (pH, DO, EC, T° and Turbidity) were determined for all samples at the spot of sampling while other physical parameters such as TSS and TDS were determined in the laboratory. AAS was used for the determination of heavy metals Pb, As, Cd, Cr, Fe, and Pb while spectrophotometer was used to determine water hardness, total chlorine, NO3-, PO43-, NH3, SO42 Alkali metals Na and K are determined by Flame Photometer. The findings indicated that the lake was found to be alkaline with pH above nine and brakish with TDS value of 2569.70 mg/L. The measured higher values of EC and turbidity resulted from higher values of TDS and TSS. Also these values are much higher than the acceptable values for surface water such as lakes. Similarly Pb, Cd, As, F- and total Cl are above the permissible values while other Physical and chemical parameter are within the acceptable limit of both WHO and FAO Guidelines for drinking and irrigation water.

Kaolin is a clay material consisting of substantially pure kaolinite. Kaolin is used in many industrial applications such as ceramic, paint and paper industries. This paper aims to study, for the first time, the beneficiation of Libya kaolin ore. Attrition scrubbing and classification were used to separate the free silica. Wet high intensity magnetic separation was applied to remove colored contaminants. The kaolinite mineral content increased from 63.5 % to 85 %. The whiteness and brightness of kaolin concentrates were efficiently improved. A final kaolin products containing 0.79 – 0.85% Fe2O3 and 0.66 – 0.68% TiO2 were obtained with whiteness about 85%.

A theoretical and experimental study on [Mn(Benzene)2]2+ has been undertaken in the gas phase. The ions were prepared using a combination of the pick-up technique and high energy electron impact, and then held in a cold ion trap where they were excited with tuneable UV radiation and further activated with methane. The following [Mn(Benzene)2 CH4]2+, [Mn(Benzene)2(CH4)2]+, [Mn(Benzene)2(CH4)2H2O)]+ and [Mn(Benzene)2CO2(CH3)2]+ were successfully identified after the experimental analysis. Two optimised geometries of [Mn(Benzene)2]2+ were observed, namely the C2V eclipse and C2 staggered . The DFT calculated binding energy of methane to manganese benzene dication complex ion [Mn(Benzene)2]2+ at BP86/6- 311++G(d, p) is 15.30 kJ/mol comparing with the calculated 20.55 kJ/mol recorded on the potential energy curve (PEC). The difference of about 5.25 kJ/mol results from the fact that the calculated charge on the manganese metal centre at the optimised geometry of [Mn(Benzene)2 CH4]2+ was 1.30 while a charge of Mn=2.0 was assumed in the PEC calculation.

The phytochemical screening, proximate composition, mineral elements and quantitative assay of anti-nutrients of the seeds of Cassia hirsute have been evaluated. The brown seeds have pungent smell and are bitter and unpleasant to taste. The phytochemical screening indicated the presence of alkaloids, tannins, saponins, phenols, sterols, triterpenes, glycosides and carbohydrates; phlobatannins and flavonoids were absent. The proximate composition of the seeds was 8.7% moisture, 7.7% ash, 7.0% fat, 10.5% protein, 13.2% fibre and 52.9% carbohydrate with estimated caloric value of 316.20 kCal/100g sample. The mineral elements determined in the seeds include K, Ca, Na, Fe, Mg and P, heavy metals such as Pb, Cr and Cu were not present. The antinutrient assay revealed that the total tannins, oxalate and phytic acid contents were high but hydrocyanic acid was not detected. The high values of these toxic materials suggest that the seeds are not suitable for consumption as food, but the solvent extract may be suitable as fumigant to dispel insects, rodents and snakes.

The Schiff base chelate of Cu(II) and Ni(II) derived from condensation reaction of salicylaldehyde and 2-aminophenol have been synthesized and investigated by different physicochemical techniques. The resulting complexes were characterized by elemental analysis, molar conductance, FT-IR, melting point or decomposition measurements, solubility in different solvent. The elemental analysis data show the formation of 1:1 metal to ligand ration. The Schiff base act as a tridentate ligand, coordinated through daprotonated phenolic oxygen and azomethine Nitrogen atom. The synthesized chelates were assayed for antibacterial activity against some pathogenic bacteria:Staphylococcus aureus, and Escherichia coli, and the fungi: Aspergillums niger and Candida albican, using dics diffusion method. The synthesized Schiff base complexes exhibit higher antimicrobial activity than the free Schiff base due to the chelation.

Structural characterization methods in Inorganic Chemistry are tools that lead every synthetic chemist to the final destination of synthesis. Therefore, in this article, the various methods of elucidating newly prepared ligands and the corresponding complexes are discussed. The methods, ranging from spectroscopic to non-spectroscopic have been discussed in principle, functions and uses.