JOURNAL of the Tunisian Chemical Society

serving the Research, the Education and the Industry

Chemical composition and antimicrobial activity of volatile fraction of the peel of Maclura pomifera fruit growing in Tunisia

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The volatile compounds from Maclura pomifera (Osage orange fruit) peel have been studied by GC-FID and GC–MS. Volatiles fraction proportion was estimated to 60 mg/kg. Identified compounds consist on aliphatics (52.6%), monoterpenes along with sesquiterpenes (27.3%), phenylpropane derivatives along with related compounds (10.0%) and other compounds (10.6%). Among the 60 identified compounds, 1-hexanol (13.5%), (Z)-Hex-3-en-1-ol (10.2%), α-cadinol (10.1%), Tetradecanoic acid (8.4%), β-eudesmol (8.3%) and Megastigma-4,6(Z),8(E)triene (5.3%) were the majors. Essential oil was tested for antibacterial activity against five strains. The oil showed a moderate antibacterial effect against Bacillus subtilis, Staphylosccus aureus, Enterobacter faecalis and Echerchia coli.

S. Fatnassi, H. Zarrouk, S. Chatti

antibacterial activity, GC-MS, hydrodistillation, Maclura pomifera, retention indice, volatile fraction

Pages 1-6

Caractérisation de la lignine extraite de l’alfa

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This paper presents a complete structural investigation of three lignin samples (crude, purified and hydrolyzed) isolated from Tunisian alfa lignin by CIMV process. Spectroscopic techniques (FTIR, NMR 1H and 13C) were used for characterising the structures of these lignins. Size exclusion chromatography and MALDI-TOF/MS were employed for analysing molecular weight distribution (Mn, Mw, Ip) and identifying lignin fragments. Lignins were also characterized by determining phenolic and aliphatic groups. The results showed the presence of S-H-G-H-G, S-H-G-H, S-H-G, S-H-H, S-H and S-G oligomers incorporating mainly (β-O-4), (β-5) and (γ-O-γ) bonds. Phenolic OH fraction is higher than that of alcoholic OH.

F. Abdelkefi, H. Ammar, B. Mlayeh, S. Abid, R. El Gharbi

Lignin, Alfa, Biopolymers

Pages 7-15

Synthèse de monomères éthyléniques issus de la biomasse végétale précurseurs de biopolymères

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New ethylenic monomers based on 1,4:3,6-dianhydrohexitols and 5-bromo-2-furaldehyde were prepared by a metal free synthesis of furannyl-isosorbide and isomannide derivatives. The monomers were obtained with high yields. The polymerization of the unsaturated monomer using 2,2’-azobisisobutyronitrile as catalyst provides the resulting polymethacrylate benzyl isosorbide with high molecular weight. The bio-based monomers and polymer were charactherized by several analitycal methods such as 1H NMR, 13C NMR and FTIR spectroscopy. Thermal properties of the polymer were investigated by means of differential scanning calorimetry (DSC) and molecular weights by SEC measurements.

H. Ben Abderrazak, R. Medimagh, S. Marque, D. Prim, H. Ben Romdhane, S. Chatti

dianhydrohexitol, 5-bromide-2-furaldehyde, ethylenic monomers, radical polymerization

Pages 17-25

Synthesis and phase transitions of fluorinated 4,4’-biphenyl derivatives

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Symmetrical fluoroalkylated 4,4’-biphenyl derivatives were synthesized starting from 4,4’-biphenol and characterized. In these compounds, the perfluoroalkyl chain is separated from biphenyl core by two kinds of spacers: allyloxy or ethyl[(3-propyloxy)sulfanyl]acetate moiety. Their thermotropic properties have been examined by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). It has been found that compounds having longer fluoroalkyl chain exhibit higher transition temperatures and melting points. Compounds whose spacer is an allyloxy group exhibit smectic phases, whereas those bearing ethyl[(3-propyloxy)sulfanyl]acetate moiety, show nematic phases.

A. Khalfallah, N. Tounsi, A. Ayari, R. Oueslati, A. Hedhli

Biphenyl, Fluorine, Liquid crystal

Pages 27-33

Etude des propriétés complexantes de dérivés du benzimidazole vis-à-vis de quelques cations métalliques

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In this work, we synthesized the 2-mercapto (2-mercaptobenzimidazolyl) benzimidazole (L) and studied its chelating properties with respect to copper (II) and silver (I). Their characterization will made by NMR 1H, NMR 13C, IR and mass spectrometry.A theoretical study carried out by the means of program AM1 of the MOPAC contained in Chem Office 2002, was made to determine dimensions, the geometry and the load of the various atoms of the ligand (L) and to determine the sites of coordination ML. The study made by IR and UV spectroscopy, on the complexation of the copper (II) and silver (I) by the 2-mercapto-(2-mercaptobenzimidazolyl) benzimidazole, showed that the formed complexes are ML in the case of Cu (II) and ML2 for Ag (I). Their formation constant will be determined. It is noted that the geometris of coordination around the atoms of Cu (II) and Ag (I) are tetrahedral.

A. Salhaji, K. El Kacemi, A. Moussaif, Z. Qafas, L. Brohmi, R. Zniber, M. El Ghoul, R. Achour

Complexation, benzimidazol, metal cation, IR spectroscopy, UV spectroscopy

Pages 51-60

Préparation, caractérisation et étude structurale d’un nouveau polyoxosélénomolybdate: K3,44(NH4)0,56Se2Mo5O21.2H2O

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The new title compound, K3,44(NH4)0,56Se2Mo5O21.2H2O, has been synthesized in aqueous solution and characterized by elemental analysis, M.E.B, thermogravimetric analysis, I.R and single-crystal X-ray diffraction. It crystallizes in monoclinic system with P21/n space group. The parameters are a = 9,911(2) Å, b = 23,350(6) Å, c = 10,501(2) Å, β = 114,10(2)° and Z = 4. Its structure is characterized by the presence of the Standberg type clusters [Se2Mo5O21]4- linked to each other to a three dimensional network by monovalent cations K+ and NH4+ and water molecules.

I. Nagazi, R. Ben Smail, A. Haddad

selenomolybdate, polyoxometallate, heteropolyanion, Strandberg, crystal structure

Pages 61-74

Dégradation chimique et photochimique de la cyfluthrine dans des eaux naturelles du Niger

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Pyrethroid insecticides are massively used in sub-Saharan Africa countries to control malaria. These chemicals are highly toxic for mosquitoes and other insects. For human and wildlife, such organic pollutants toxicity rate is a function of their environment bioaccumulation capacities. In this work we studied cyfluthrin chemical and photochemical degradation in local natural waters. Cyfluthrin is rapidly hydrolyzed in distilled water than in river and pond waters. Indeed, in little acidic aqueous media, its hydrolysis half-life time is 27, 205 and 3099 days respectively. Under UV-visible irradiation, the insecticide photolysis rate which is very important in distilled water decreased in natural waters. Under less intense neon lamps (18W), it is photolytically more stable in river water than in pond water. With intense simulated solar irradiations (200W), the insecticide is more stable in Niger River water (t1/2 = 693h) than in pond water (t1/2 = 495h). Here, the photolysis reactions induced by interfering reactive radicals in pond water are more important than the screen role played by the medium dissolved organic matter.

R. Adamou, A. Abdoulaye, M. Soumaila, I. Moussa, A. Coly, A. Tine, K. Ikhiri

pyrethroid insecticides, cyfluthrin, hydrolysis, photolysis, natural waters

Pages 75-83

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