JOURNAL of the Tunisian Chemical Society

serving the Research, the Education and the Industry

Etude de la réactivité des esters sulfamiques 683 vis-à-vis du 2-fluoro-2-phényléthyl ptoluènesulfonate

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The action of 2-fluoro-2-phenylethyl p-toluenesulfonate on the sulfamic esters under phase transfer catalyst solid-liquid, gives corresponding β-fluoroethers. In the case of 2,4,6- trimethylphenyl sulfamate, N-disubstituted sulfamic ester was formed.

M. Béji, M.M. Chaabouni, A. Baklouti

Pages 683-687

Analysis of polycyclic aromatic hydrocarbons by ITD mass spectrometry and comparison with GC and LC chromatographic techniques. Applications: Airborne particulate

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A method for the simultaneous analysis of nineteen Polycyclic Aromatic Hydrocarbons (PAH), 11 of which are included in the priority pollutants list of the US Environmental Protection Agency (EPA), was designed for their determination in airborne particulate. PAHs analysis was carried out by different analytical techniques: reversed-phase liquid chromatography with Ultraviolet detection and wavelength programming (LC-UV), capillary gas chromatography with Flame Ionisation (GC-FID) and Mass Spectrometry (GC-MS) with Ion Trap Detector (ITD). The minimum amounts detectable with the various techniques were determined for each compound. They lay respectively between 0.05 and 0.2 ng on LC-UV, between 1.5 and 5 ng on GC-FID and between 0.5 and 4 pg on GC-ITD-MS. PAHs separation was achieved on 5 µm polymeric C-18 column in LC and on two different capillary columns in GC. Samples were extracted by acetonitrile using Soxhlet extraction. The purification step was assessed for each analytical technique. These methods were applied for the determination of PAHs in three locations in Tunis. For studied samples, ten PAHs were detected and quantified. Moreover, PAHs levels were in relation ship with traffic rate in studied locations.

S. Dridi, S. Sabbah, M.S. Medimagh

PAH, Mass Spectrometry, Ion Trap Detector, airborne particulate

Pages 689-703

Plasma degradation of organic compounds: Oxidation of 1,4-dihydroxybenzene

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1,4-Dihydroxybenzene (hydroquinone) is selected as a model molecule to investigate the oxidising properties of a low pressure inductively coupled oxygen plasma discharge on organic powders. The formation of 1,4-benzoquinone and acids is observed as intermediates in a complex mechanism which ultimately yields carbon dioxide. The main steps of the oxidation process are given with the relevant kinetic constants. The influence of the discharge parameters is considered. The technique appears to be efficient for the ageing study of organic powders.

N. Bellakhal, J.L. Brisset

Non-thermal plasmas, Oxygen, Low pressure electric discharge, Oxidation, Dihydroxybenzene

Pages 705-714

Préparation et étude structurale du tripotassium cérium(III)bis-arséniate: K3Ce(AsO4)2

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The tripotassium cerium(III)bis-arsenate K3Ce(AsO4)2 cristallizes in the monoclinic system, space group P21/m. The parameters of the unit cell are a = 7.607(1) Å; b = 5.837(3) Å; c = 9.879(1) Å and β = 91.20(1)°; Z = 2. The structure was determined using 851 independent reflections and refined untill (R(F) = 0.038; wR(F2) = 0.103). It consists of [Ce(AsO4)2]n3n- infinite layers, parallel to (100) plane, built up from AsO4 tetrahedra alternated with CeO7 decahedra sharing-corners. The K+ cations are located in the interlayer space. K3Ce(AsO4)2 is isostructural with the analogous K3Ce(PO4)2 and K3Nd(PO4)2. A comparison with the structure of K3Na(SO4)2 reveals a narrow analogy.

W. Belam, M. F. Zid, A. Driss, A. Daoud

Pages 715-722

Structure et propriétés physicochimiques du 1,2-diammonium propane sulfate

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A new organic sulfate C3H12N2SO4, (DAPS) is prepared by interaction of H2SO4, with the organic molecule 1,2-diamino propane. We describe its crystallographic and structural features. The thermal behavior and spectroscopic properties are given for this compound which crystallizes in the monoclinic system P21/n, Z=4 with the parameters: a= 5.540(2), b= 15.667(3), c= 8.506(2) Å, β= 104.13(2)°, ρm= 1.579 g/cm3, ρc= 1.598(7) g/cm3, µ= 0,415 mm-1. The asymmetric unit of the crystal consists of one sulfate anion and one organic cation. The structural cohesion is established by a three dimensional network of N-H...O hydrogen bonds. Phase transitions are observed in the DAPS. Their total endothermic enthalpy is 107.72J/g. The IR spectrum is discussed by comparison with spectra of similar compounds.

T. Guerfel, A. Jouini

Pages 723-734

Elaboration et étude radiocristallographique 735 du trisodium yttrium-aluminium triarsenic dod.caoxyde Na3Y0.11Al1.89(AsO4)3R. Effet du dopage par Na2O sur la conductivité électrique

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The trisodium yttrium-aluminum triarsenic dodecaoxide Na3Y0,11Al1.89(AsO4)3, synthesized by solid-state method and characterized by single-crystal X-ray diffraction, crystallizes in the rhombohedral system, space group R3c . The parameters of the hexagonal cell are a = 13.354(1) Å; c = 18.335(3) Å and Z = 12. The structure was determined using 538 independent reflections and refined until (R(F) = 0,038; wR(F2) = 0.109). It is built of a three-dimensional framework [Y0.22Al3,78(AsO4)6]n6n- into which the sodium cations Na+ are inserted. The framework is made up of Al4O18 clusters( three Al(2) octahedra sharing an edge with a central octahedron Al(1)) and YO6 octahedra linked to AsO4 tetrahedra. Each tetrahedron shares two oxygen atoms, O(2) and O(3), with a first cluster Al4O18 and one oxygen atom, O(1), with a second cluster, the fourth oxygen atom, O(4), is connected to the Y(O(4))6 octahedron. The structure of this compound is compared with the Nasicon-type phosphates Na3M2(PO4)3. The impedance spectroscopy measurements were used to evaluate the variation of electrical properties, vs the doped rate by Na2O, of this material.

W. Belam, A. Madani, A. Driss, A. Daoud

Pages 735-743

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