Volume 15, No. 1 (2014)
Articles
CYCLIC VOLTAMMETRY STUDIES OF COPPER (II) AND TELLURIUM (IV) IONS IN ACIDIC AQUEOUS SOLUTIONS FOR THIN FILM DEPOSITION
Saravanan Nagalingam(1*), Geok Bee Teh(2)
Cyclic voltammetry studies of copper (II) and tellurium (IV) ions in acidic aqueous solutions were carried out to determine the optimum condition for copper telluride thin film deposition. The voltammetry studies include reversible scans at different solution pH. Based on the voltammogram, suitable deposition conditions was determined to be in the range of -0.35 V to -0.45 V versus Ag/AgCl at pH values between 2.0 to 2.2 under non diffusion-limited conditions.
INFLUENCE OF MgO ON MICROSTRUCTURAL AND MECHANICAL PROPERTIES OF RAW CLAY FROM BURKINA FASO
Mohamed Seynou(1*), Younoussa Millogo(2), Lamine Zerbo(1), Raguilnaba Ouedraogo(1)
The influence of MgO on mechanical and microstructural properties of raw clay material from Burkina Faso was investigated by means of X-ray diffraction, scanning electron microscopy, infrared spectroscopy, differential thermal analysis and numerical simulation. The mineralogical composition was modified with the formation of new crystalline phases such as mullite, spinel – Mg, enstatite and forsterite. During the sintering and with add of MgO, the mullite quantity decrease contrary to forsterite and affect the different properties of sintered products. The mechanical properties were improved with MgO amount around 2 – 5 wt%. For magnesia amount higher than 5 wt%, the magnesia is not entirely consumed and is originated to the formation of pores in the manufactured products which are detrimental to the mechanical properties.
BEHAVIOUR OF SOME ISOLATED AND CONJUGATED UNSATURATED COMPOUNDS, ARENES AND AROMATIC HETEROCYCLES IN A Ni-Al/NaOH REDUCING SYSTEM
Mirela Suceveanu(1*), Matei Raicopol(2), Adriana Fînaru(1), Sorin I. Roşca(2)
In this paper we present the results of some experiments in which substrates representing various unsaturated and aromatic systems were tested in reduction reactions with Ni-Al alloy in aqueous NaOH and we highlight the relationships between the structure and the reactivity of the investigated compounds. We have found that unsaturated compounds containing isolated double bonds carbon-carbon and polynuclear condensed ring aromatics present an advanced inertness to the reduction process by the aluminum component of the Ni-Al/NaOH system. Unlike them, unsaturated compounds with C=C conjugated bonds are very reactive to the Ni-Al/NaOH system, 1,4 reduction processes being facilitated, behaviour attributed to the polar nature of the conjugated systems. The heterocyclic compounds have a higher reactivity than their homologues carbocyclic compounds.
EVALUATION OF POLLUTION GENERATED BY LANDFILL LEACHATE PUBLIC OF THE CITY OF MOHAMMEDIA AND ITS IMPACT ON THE GROUNDWATER QUALITY </br> EVALUATION DE LA POLLUTION GENEREE PAR LES LIXIVIATS DE LA DECHARGE PUBLIQUE DE LA VILLE DE MOHAMMEDIA ET SON IMPACT SUR LA QUALITE DES EAUX SOUTERRAINES
Abderrahim Idlahcen(1), Salah Souabi(1*), Abdessalem Taleb(1), Khadija Zahidi(1), Mohammed Bouezmarni(2)
The diagnosis of the leachate has shown a strong no biodegradable (COD/BOD5 varies between 3 and 50) organic pollution. High NTK concentrations vary between 2296 and 490 mg∙L-1 have been observed which can induce a nuisance of surface water near the discharge and receiving of leachate. The analysis of metallic elements of leachate showed a high concentration in chrome 1598 µg∙L-1 as maximum value and 27 µg∙L-1 as minimum and maximum high in As, Cu, Ni, Pb and Zn which testifies to the pollution of leachate from the discharge gross receiving every type of waste (management waste and industrial waste). The results showned that P1, P3, P5, P6, P8, P9, and P10 have high concentrations in NO3- (389 and 111 mg∙L-1) exceeding the standards of potability (50 mg∙L-1). Sinks P1, P5, P7, P8, P9 and P10 are highly mineralized since the conductivity varies between 5990 and 1480 µS∙cm-1, while the organic matter remains higher than the standard of 2 mg∙L-1 The analysis of metallic element in groundwater have shown significant concentrations in Ni (175 and 59 µg∙L-1), Zn (266 and 6 µg∙L-1) and Pb (165 and 30 µg∙L-1) confirming the degradation of groundwater. These results show that the public discharge has a considerable impact on the groundwater near the discharge.
SOME BENZYL CARBOXYLATO DERIVATIVES AND ADDUCTS: SYNTHESIS, INFRARED AND NMR STUDIES
Daouda Ndoye, Libasse Diop(*)
Cy2NH2BzCO2•SnPh3Cl, Bz2NH2BzCO2•SnPh3Cl, BzCO2SnPh3•SnPh3Cl•1/4Bz2NH2Cl, Bz2NH2BzCO2•SnPhCl(OH)2, Bz2NH2BzCO2•SnBu2Cl2, [BzCO2SnPh3][SnPhCl3•EtOH•H2O] adducts and complexes have been obtained on allowing Cy2NH2BzCO2 or Bz2NH2BzCO2•4H2O to react respectively with SnPh3Cl, SnPh2Cl2 or SnBu2Cl2 in specific ratios. The molecular structures of these compounds have been determined on the basis of infrared and NMR data. The suggested structures are discrete, dimers and tetramer, the tin atom being tetra-, penta- and hexacoordinated; the benzyl carboxylate anions are monodentate, bidentate and chelating and the cations involved in hydrogen bonds.
PHYTOCHEMISTRY, ANTIMICROBIAL AND ANTIRADICAL ACTIVITIES EVALUATION OF ESSENTIAL OILS, ETHANOLIC AND HYDROETHANOLIC EXTRACTS OF THE LEAVES OF EUCALYPTUS CITRIODORA HOOK FROM BENIN
Yaya A. Koudoro(1), Cokou P. Agbangnan Dossa(2), Boniface B. Yèhouénou(1), Fidèle P. Tchobo(3), Guy A. Alitonou(1), Felicien Avlessi(1), Dominique C. K. Sohounhloué(2*)
The precipitation and coloration reactions implemented in this study revealed in the leaves of E. citriodora (Myrtaceae) of Benin the presence of polyphenols, anthocyanins, flavonoids, saponins, tannins, mucilages, anthraquinones, leucoanthocyanins, cardiac glycosides, coumarins, proteins, sterols and triterpenes. The essential oil from the leaves of this plant was extracted with a yield of 3% and then analyzed by GC/MS. Nine compounds, representing 94.46% of the chemical composition of the oil, were identified, three among them being majority: citronellal (65.45%), citronellol (13.5%) and isopulegol (10.33%). The contents of polyphenolic compounds of ethanolic and hydroethanolic extracts were respectively 4.52 mg EAG.g-1 and 4.38 mg EAG.g-1 for total polyphenols, 78.76 mg EC.g-1 and 81.56 mg EC.g-1 for total flavonoids and 62.62 mg EC.g-1 and 67.09 mg EC.g-1 for condensed tannins. The radical scavenging activity of hydroethanolic extract (IC50=0.23 mg.mL-1) was more pronounced than that of ethanolic extract (IC50=0.42 mg.mL-1) and essential oil (IC50=0.9 mg.mL-1). Regarding antimicrobial activity, Staphylococcus aureus and Candida albicans were sensitive to hydroethanolic extract of E. citriodora leaves while Escherichia coli developed resistance against this extract. As for the essential oil extracted from the leaves of Eucalyptus citriodora it showed fungicidal activity against Candida albicans and bacteriostatic with Escherichia coli and Staphylococcus aureus.
PHOSPHATO AND PHOSPHONATO ADDUCTS: SYNTHESIS AND SPECTROSCOPIC STUDY
Mouhamadou Birame Diop, Libasse Diop(*)
Two new adducts have been synthesized and studied by infrared and NMR spectroscopy. The suggested structures are discrete or of infinite chain type with a phosphate behaving as a bidentate ligand, a phosphonate acting as a monodentate ligand, the environments around the tin centre being tetrahedral or trigonal bipyramidal. In all the studied compounds, supramolecular architectures are obtained when hydrogen bonds are considered.
HZSM-5 CATALYST FOR CRACKING PALM OIL TO BIODIESEL: A COMPARATIVE STUDY WITH AND WITHOUT PT AND PD IMPREGNATION
Agus Budianto(*), Danawati Hari Prajitno, Achmad Roesyadi, Kusno Budhikarjono
The Needs of healthy environment and green energy poses a great demand for alternative energy. Biofuel is one of the alternative energy products that are environmentally friendly. Biofuel can be made from plant oils, especially palm oil. Cracking of palm oil into biofuel is constrained by the availability of catalysts. Moreover the available catalyst still gives a low yield. This research aims to study the effect of Pt and Pd impregnation into HZSM-5 catalyst on the catalytic properties. Another aim is to obtain the operating conditions of the catalytic cracking process of palm oil into biofuel which gives the highest yield and selectivity, especially for biodiesel and biogasoline fractions. Catalytic cracking process was carried out in a micro fixed bed reactor with diameter of 1 cm and length of 16 cm. The reactor was filled with a catalyst. The results of the study successfully prove that Pt and Pd impregnated into HZSM-5 catalyst can increase the yield and selectivity of biodiesel. Pd and Pt are highly recommended to increase the yield and selectivity of biodiesel.
CRYSTAL STRUCTURE OF (Cy2NH2)2MoO4.2H2O
Serigne Fallou Pouye(1), Ibrahima Cissé(1*), Libasse Diop(1), Kieran Christopher Molloy(2), Gabriele Kociok-Kohn(2)
The structure of this salt consists of a 3D structure. The anion interacts with NH2 group of the cation and H2O molecules respectively through N-H---O and O-H---O hydrogen bonds. The anion MoO42- is almost perfectly tetrahedral. The four values of the lengths of Mo- O bonds are all equal to 1.7613 Å (12).
(Me4N)2O2CSO3Sn(O2CSO3)2.7Me4NSnCl5: SYNTHESIS AND INFRARED STUDY
Daouda Ndoye, Libasse Diop(*)
On allowing Me4NO2CSO3H (in water) to react with SnCl4 (in ethanol) the studied complex is obtained. The suggested structure is discrete, the anion behaving as a polydentate and chelating ligand, the environment around tin being octahedral.