Applied Chemistry

A methodology based on flame atomic absorption spectrometry (FAAS) was developed and validated to quantify lithium in spodumene mineral sample. Validation parameters, including linearity and range, precision, accuracy, limit of detection (LOD) and limit of quantification (LOQ), were evaluated. The method is linear over 1.0 – 9.0 µg mL-1, with a coefficient of correlation (r) > 0.999. The LOD and LOQ were 0.2 ?g mL-1 and 0.7 ?g mL-1. This method is very precise; intraday precision measurements had a relative standard deviation (RSD) value of 4.00 %. This RSD value was lower than that required by Horwitz. The mean recovery percentage was 99.06 %, indicating that this method could accurately quantify the lithium in the studied mineral. The percentage of lithium oxide in the spodumene mineral sample was 0.33 –0.39%.

Thisstudy compares the heat transfer coefficients for film and dropwise condensation of steam.Copper tube was coated with oleic acid to promote dropwise condensation of steam rather than a continuous film. Excellent dropwise condensation was observed when the cooling surface was coated with oleic acid, and this helps to enhance droplet formation without wetting the surface.The experimental results shows that the value of overall heat transfer coefficient is 50000 W/m2K in dropwise and 12500W/m2K in filmwise condensation.Thus, theoverall heat transfer coefficients during dropwise condensation are approximately four times greater than those during filmwise condensation at the same surface subcooling degrees.

Early studies on the adsorption and ion exchange potential of coconut coir dust (Cocos nucifera L.) shows that it has great proficiency for removal of trace metal ions from waste water and industrial effluents. Several factors influence the process of waste water detoxification by agricultural biomass. In this paper the effect of Particle sizes of coconut coir dust on the removal of metal ions by ion exchange has been studied by batch adsorption process for Pb(II), Zn(II), Cu(II), and Cd(II). Percentage sorption of Pb(II), Cu(II), Cd(II), Zn(II) increase with decrease in particle sizes of coir dust: 50 µm > 63 µm > 150 µm > 212 µm > 300 µm > 425 µm > 600 µm. The adsorptivities of the metal ions on the unmodified coir dust decreased in the descending order: Pb(II) > Cd(II) > Zn(II) > Cu(II).

Calotropis procera R. Br. (Asclepiadaceae) is a well-known medicinal plant with leaves, roots, and bark being exploited by popular medicine to fight many human and animal diseases. This work deals with the fractionation of the crude latex produced by the green parts of the plant and aims to evaluate its toxic effects upon egg hatching and larval development of Aedes aegypti. The whole latex was shown to cause 100% mortality of 3rd instars within 5 min. It was fractionated into water-soluble dialyzable (DF) and non-dialyzable (NDF) rubber-free materials. Both fractions were partially effective to prevent egg hatching and most of individuals growing under experimental conditions died before reaching 2nd instars or stayed in 1st instars. Besides, the fractions were very toxic to 3rd instars causing 100% mortality within 24 h. When both fractions were submitted to heat-treatment the toxic effects were diminished considerably suggesting low thermostability of the toxic compounds. Polyacrylamide gel electrophoresis of both fractions and their newly fractionated peaks obtained through ion exchange chromatography or desalting attested the presence of proteins in both materials. When submitted to protease digestion prior to larvicidal assays NDF lost most of its toxicity but DF was still strongly active. It may be possible that the highly toxic effects of the whole latex from C. procera upon egg hatching and larvae development should be at least in part due to its protein content found in NDF.

Densities, viscosities and ultrasonic velocities have been measured for the binary mixtures of anisic aldehyde with methyl acetate, ethyl acetate and n- butyl acetate over the entire composition range at 303.15,308.15,313.15 and 318.15K .The excess values were correlated using Redlich – Kister polynomial equation. The excess values were examined in order to have an insight into the inter molecular interactions among the components of the binary mixtures that lead to the possible dipole- dipole interactions or hydrogen bond formation between unlike molecules. Excess molar volumes, deviation in adiabatic compressibilities, deviation in viscosity and excess free length are negative in the whole composition range for all the systems at all temperatures.

A Schiff base ligand derived from salicylaldehyde and 2-aminophenol and its complex of Co(II) were synthesized. The ligand and the complex were characterized by elemental analysis, conductivity measurement, FT-IR and melting point or decomposition temperature measurements. The elemental analysis data show the formation of 1:1 metal to ligand ratio. The experimental data show that the ligand act as a tridentate ligand (ONO). The Schiff base and the complex were screened for antibacterial and antifungal activity. The complex shows higher activity than the free ligand.

In the title compound, C22H19ClN4, the pyrrole and pyrimidine rings form a dihetrocyclic fused pyrrolo-pyrimidine ring system which is almost co-planar; dihedral angle between two ring planes is 6.2º, to which five membered pyrrolidine ring is substituted, which is puckered to attain half chair conformation. Two other rings chloro-phenyl and phenyl are substituted at the 7 and 9 positions respectively in the fused ring system. Chloro-phenyl ring also shares the plane of fused ring system. (Dihedral angle between two ring system is 12.4º.) Crystal packing is stabilized due to ?-? interaction observed between pyrrole and chloro-phenyl ring of its symmetry related molecules (centroid-centroid distance: 3.8641 Å). Intramolecular C-H…N hydrogen bond is also observed in the molecular structure.

Omeprazole is chemically 5-methoxy-2-[[(4-methoxy-3,5-dimethyl-2-pyridinyl) methyl] sulfinyl ]-1H benzimidazole. It works by blocking acid production in the stomach. This medication is known as a proton pump inhibitor (PPI). It is used to treat acid-related stomach and throat (esophagus) problems and also used in the treatment of dyspepsia, peptic ulcer disease (PUD), Gastro esophageal reflux disease (GORD/GERD), and Laryngopharyngeal reflux (LPR) and Zollinger–Ellison syndrome. From the literature survey conducted there is no simple method reported for the determination of Omeprazole in capsule dosage form. Hence an attempt has been made to develop a HPLC method for the determination of Omeprazole is capsule dosage form and validate the developed method. The method was validated with respect to linearity, precision, system suitability, and specificity. The response was linear in concentration range of 9.6µg/ml to15.6µg/ml. The value of correlation coefficient found to be 0.9992. The R.S.D% value for repeatability precision studies was 0.8500. For system suitability it is essential for the assurance of the quality performance of chromatographic system so five injections of standard drug solution were given to the system. The %RSD value for system suitability was 0.1645.

Chemical speciation and mobility factor indices of Pb, Cd, Zn and Mn were assessed in a crude oil contaminated soil and compared with control (uncontaminated) soil. The assessment was done to evaluate the impact of crude oil contamination on the bioavailability of metals in a soil matrix. Soil was collected in triplicate from four locations (three reflecting the crude oil impacted area and one uncontaminated soil as control). Soil was collected around a crude oil transfer pipeline within Bdere community in Ogoniland, Nigeria, within the month of August 2017. Fractional concentration of metals was determined using a GBC Avanta PM6600 atomic absorption spectrophotometer. In the oil contaminated soil, Zn (41.13%) and Mn (77.54%) were predominantly associated to the residual fractions while Pb (29.45%) and Cd (25.53%) were prevalent in the amorphous Fe-oxide and plant available fractions respectively. Similarly, the uncontaminated soil depicted the residual fractions of Zn (49.43%) and Mn (48.63%) to be the most important while Pb (56.17%) and Cd (62.16%) were both predominantly affiliated to plant available fractions. Heavy metal mobility factor indices reflected the order: (Zn>Cd>Pb>Mn) and (Cd>Mn>Zn>Pb) for crude oil impacted and uncontaminated soils respectively. Despite the prevalence of heavy metals to the inert fractions, the significant affiliation of metals to the readily mobile fractions of crude oil contaminated soil reflected the order: Pb (10.71%), Cd (25.53%), Zn (40.22%) and Mn (3.52%) which further suggested that these metals may have emanated from the introduction of crude oil into the soil matrix.

Energy demand is increasing while fossil fuels, the main source of energy, threaten their depletion and consequently their market value increases. In addition to this crisis, climate change and air pollution caused by the combustion emissions of fossil fuels pose problems of increased greenhouse effect. Due to the environmental problems caused by the use of fossil fuels, attention has been paid to the production of biodiesel as an alternative to petrodiesel. Biodiesel is an environmentally friendly alternative diesel fuel made from renewable resources made from vegetable oils and animal fats. It is a renewable energy source that seems to be an ideal solution for global energy needs. The current method of biodiesel production is the transesterification of the inedible oil with an alcohol (methanol or ethanol) in the presence of a catalyst or not. The transesterification reaction is very sensitive to the parameters and oil nature such as the acid composition and the free fatty acid content. Other variables include reaction such as temperature, ratio of alcohol to vegetable oil, catalyst, and intensity of mixing, purity of reagents. The development of biofuels creates new agricultural sectors and could offer new niche markets for farmers in exploitable areas. This study aims to make a comparative study transesterification processes for biodiesel production.