Current Research and Development in Chemistry Vol. 1

Thallium (Tl) is a non-essential element for human being and is considered as a highly toxic trace element at a concentration above 2 µg/L. To assess the source of thallium contamination in ground and surface waters in the locality of Yamtenga village (11°43'35.1'' N and 00°11'50.8'' W, Burkina Faso), chemical analyzes of thallium concentrations in the soils of Yamtenga village along with geological descriptions (geological map and hydrographic watershed map of the studied area) were undertaken. We found thallium concentrations in this area ranging from 1.61 mg / kg to 404.75 mg / kg. A zoned mineralization in thallium, due to the geological structure of the locality, was established in the soils, suggesting that the source of thallium contamination in ground and surface waters in the locality of Yamtenga village is of natural origin. The concentration of some heavy metals (Pb, Zn, Cd, Cu and Mn) were also evaluated in the soils of Yamtenga village and their concentration relationships with thallium were analyzed by the Pearson correlation coefficient based on matrix correlation. Moderate (0.554), low (0.408) and significant (0.999) correlations coefficients were obtained between thallium and lead, zinc, manganese respectively. Significant correlation coefficients (0.788 and 0.791) were also noted between thallium and copper, cadmium respectively. Thallium concentrations in ground and surface waters in this locality are mainly related to the interactions between water and source rocks, thallium being released following some alteration processes with other heavy metals elements especially manganese.

Photochromic 5-phenylpyrazolidin-3-one-basedazomethine imines containing 2-benzylidene 1, 2-(3-nitrobenzylidene) 2, 2-(4-nitrobenzylidene) 3, 2-((1H-imidazol-2-yl)methylene) 4, 2-(pyridin-2-ylmethylene) 5, 2-(quinolin-2-ylmethylene) 6 and 2-((8-hydroxyquinolin-2-yl)methylene) 7 substituents were synthesized. All the compounds exist in the ring-opened O forms. Under irradiation with light of 365 nm, compounds 1-7 undergo thermally reversible isomerization into ring-closed bicyclic diaziridine isomers C. Azomethine imines 4-6 exhibit properties of ion-active molecular “off-on” switches of fluorescence when interacting with F^- or AcO^- anions. Compound 7 represents bifunctional chemosensor demonstrating a colorimetric “naked-eye” effect for Ni²⁺cation and complete fluorescence quenching in the presence of H⁺, F^– and CN^– ions.

Solid-phase microextraction (SPME) coupled with gas chromatography-isotope ratio mass spectrometry (GC-IRMS) has already been applied to collect and identify volatile light hydrocarbons in oil and source rocks.  However, this technology has not yet been used to analyze volatile light hydrocarbons in dry gas (natural gas with C₁/C₂₊>95%). In this study, we developed a method to measure the molecular and carbon isotope composition of natural gas using Divinylbenzene/ Carboxen/Polydimethylsiloxane (DVB/CAR/PDMS) fiber. This fiber proved to be suitable for extracting C₁–C₉ hydrocarbons from natural gas without inducing carbon isotopic fractionation. Notably, the extraction coefficients of the analytes were not the same, but rather increased with the increasing carbon number of the hydrocarbons. Nevertheless, we successfully identified 24 hydrocarbons from the in-lab standard natural gas, while also obtaining the carbon isotope composition of C₁ to C₉ hydrocarbons with satisfying repeatability. The relative standard deviation (RSD) of the molecular composition data was in the range of 0.06–0.74%, with the RSD of the carbon isotope composition data not exceeding 1‰. Finally, seven natural gas samples, collected from different sedimentary basins, were successfully analyzed and the stable carbon isotope compositions of C₁–C₉ hydrocarbons present in these were determined through this method.

The oxidation of diazepam (DZ) by N-Bromosuccinimide (NBS) in aqueous acid medium follows a first-order kinetics in [NBS] and a fractional-order each on [HCl] and [DZ]. The reaction stoichiometry involves one mol NBS consumed by one mol DZ. The rate of the reaction increases with the decrease in dielectric constant of the medium. Added products and the variation of ionic strength have no significant effect on the rate of the reaction. The oxidation products were identified by spectral analysis. A mechanism involving the formation of an intermediate NBS-DZ complex has been proposed. The solvent effect is consistent with the charge dispersion going into the transition state. The activation parameters for the reaction have been determined. The negative entropy of activation suggests the formation of a rigid, associative transition state involving loss of degrees of freedom

Aims: This study investigates the use of sawdust from 3 hardwood species as low-cost adsorbent for the removal of copper from contaminated water.

Study Design: The experimental design used for this study was 3 x 2 x 4 factorial experiment; the different sawdust species, two baselines (treated and untreated) and four levels of pH and time as factors were combined and used for the study.

Methodology: Test was carried out to investigate the effect of sawdust pre-treatment on their adsorption capacity in the removal of Copper ions from contaminated water at different pH levels; the sawdust samples were sieved through a screen size of 850 μm after which a portion of each species sawdust was subjected to pre-treatment by boiling while the other portions were maintained as control samples (untreated).

Results: The results shows that adsorption capacity for both treated and untreated samples were 69.75±13.78%,  68.60±19.48%, 69.34±23.08%, 74.79±17.79%, 74.52±22.30% and 76.90±18.21% for  Alstonia boonei, Erythrophleum suaveolens  and Ficus mucuso  respectively.

Conclusion: The contact time and pH showed no significant difference between the treated and untreated samples. Sawdusts from the selected wood species are suitable to be used as adsorbent towards the removal of copper from contaminated water.

Racemic stiripentone was synthesised from piperonal and pinacolone and reduced to the alcohol stiripentol, which was obtained in high yield. Kinetic resolution of stiripentol catalysed by lipase A from Candida antarctica via esterification with vinyl butanoate has been performed with an E-value of 24. This allowed isolation of (3S)-stiripentol with an enantiomeric excess (ee) of 86% and the corresponding (3R)-butanoate with an ee of 87%. Enzymatic hydrolysis of the ester product gave (3R)-stiripentol with an ee of 94%. Additionally, a novel one-pot two-step pathway for the synthesis of 5-vinylbenzo[d][1,3]dioxole starting from (E)-3,4-dihydroxycinnamic acid has been developed. Lipase catalysed esterification of 4,4-dimethylpent-1-en-3-ol afforded (R)-(+)-4,4-dimethylpent-1-en-3-ol and an ee >99% of (3R)-stiripentol was obtained via cross metathesis of this compound coupled with 5-vinylbenzo[d][1,3]dioxole.  

This study investigates the concentration of Heavy Metals in soil sample from 15 different locations in Garki area of Federal Capital Territory (F.C.T) Abuja, Nigeria. The soil PH of the sample sites varies on the average from 6.44 to 7.24 in water indicating only a slightly acidic to neural. The level of Cu, Cd, Pb, Ni, Mn, and Zn were determined using flame atomic absorption spectrophotometer. The results obtained indicated that these metals on dry weight basis in the soil ranged between (36.60-525.0 µg/g) Pb, (15.00-74.40 µg/g) Cu, (17.50-29.80 µg/g) Zn, (0.7-2.20 µg/g) Cd, (16.16-24.60 µg/g) Ni, and (270-558.0 µg/g) Mn. From the results, areas with high traffic density seem to be relatively high in concentration of tested metals than those from less traffic density. A significant correlation was found between traffic density and metal concentrations.

 Generally, the concentrations obtained were much higher than the tolerable limit for safe environment as prescribed by National Environmental Standards and Regulations Enforcement Agency (NESREA) and World Health Organization (WHO).

Cassava is consumed in many tropical countries and is fast becoming the major raw material of many diets, especially in the bakery, brewery and pharmaceutical industries. In a study to determine the effects of various formulations of Cassava feeds on blood lipid profile in rats. Forty adult Wistar rats weighing between 120 and 150 g were divided into 4 groups of 10 rats each. The rats were acclimatized for one week; fed with different formulations of Cassava feeds adlibitum, after which the rats were allotted into groups. Group 1 was fed on Garri; group 2 on Cassava flour; group 3 on Tapioca, and the control group (group 4) on normal chow. After 4 weeks, each animal was anaesthetized by exposure to chloroform vapour and blood samples collected by cardiac puncture. Group 1 diet (Garri) significantly increased HDL-cholesterol (HDL-C) concentration and significantly decreased LDL-cholesterol (LDL-C) concentration (p<0.05) compared with the control group. In Group 2 (Cassava flour), there was significant increase in the concentration of HDL-C (p<0.05). Group 3 (Tapioca) had a significant increase in TC, TG, LDL-C concentrations (p<0.05), but an insignificant increase in HDL-C concentration (p<0.05) when compared with the control. In conclusion, our findings suggest that Garri and Cassava flour but not Tapioca enhanced HDL-C in the blood, with Garri proving to be the better of the two.

Performance in chemistry of form two national examinations in Zanzibar government schools have not been encouraging since 2009 to date despite several attempts made through additional carefully planned instructional strategies and models to improve the status of teaching and learning chemistry. From the performance data of 31 government schools sampled gotten from the Ministry of Education and Vocational Training Zanzibar shows the average mean score is 30.16 with a mean standard deviation of 2.1995 while those who passed are 30 ± 10%. With percentage pass mark set at 35%, performance has been poor and persistent. Conclusively, enhancement of teachers’ effectiveness, improved economies of education and setting aside fewer schools for science studies is mandatory. The study recommends heuristic approach of teaching intertwined with instructional objectives to bring learners into meaningful learning and effective understanding guided by the four domains of Bloom’s taxonomy with more motivational orientations and innovations.

For over two decades, research on the biological and analytical applications of calixarenes and their derivatives has been shown remarkable properties towards organic and bioorganic molecules. Applications in the field of analytical chemistry and biological activity, as well as the anticancer properties of various calixarenes, have been studied and reported by several research groups. Due to their superior geometrical shape, calix[n]arenes structures (with n = 4; 6 or 8) have a special function, moreover, when combined with functional groups, the calixarenes can dissolve well and the low toxicity of the cell and the ability to form stable complexes with metal ion, especially the ability to transport drugs, it is allowed to be applied in the analysis and development of biosensors in fields: Biotechnology and drug discovery calixarene derivatives. The applications of calixarenes and their derivatives are summarized in this review, and future development prospects will be discussed.

From experiences all over the world we know that formulae and chemical equations are memorized very often or are equalized by counting the number of „atoms on the left and right side of the equation“. Looking to our Chemical triangle (Fig. 1) lecturers and students are jumping from the Macro level just to the Symbolic level. If we would go first from Macro level to Submicro level and explain chemical reactions with involved atoms, ions and molecules, learners would understand chemistry more successfully. With a special questionnaire we are investigating the ability of university students and chemistry teachers in Indonesia, Tanzania and Germany to interpret given chemical equations with involved particles. We found a lot of misconceptions and proposed how to challenge them.

The conductivity of an electrolyte plays a significant role in deciding the performance of any battery over a wide temperature range from –40°C to 60°C. In this work, the conductivity of lithium bis (trifluoromethanesulfonyl) imide (LiTFSI) at a varied salt concentration range of 0.2 M to 2.0 M in a multi-solvent organic electrolyte system over a wide temperature range –40°C to 60°C are reported. The mixed solvents used were 1, 3-dioxolane (DOL), 1, 2-dimethoxyethane (DME), and tetraethylene glycol dimethyl ether (TEGDME) with an equal ratio of DOL: DME: TEGDME (1:1:1 by volume). The experimental analysis performed over the wide temperature range revealed the maximum conductivity at salt concentrations ranging from 1.0 M to 1.4 M for equal molar solvents. The optimum salt concentration and maximum conductivity in a different solvent composition ratio (i.e., 3:2:1) for all the temperatures is reported herein. The temperature-dependence conductivity of the salt concentration did not fit the Arrhenius plot but it resembled the Vogel-Tamman-Fulcher plot behaviour. The present conductivity study was carried out to evaluate the overall operable temperature limit of the electrolyte used in the lithium-sulfur battery.