JOURNAL of the Tunisian Chemical Society

serving the Research, the Education and the Industry

Synthèse et caractérisation d’un nouveau hybride dimalonato tétraaqua cobalt (II) [Co(C4H3O4)2(H2O)4]

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The title compound was synthesized by slow evaporation of solution at room temperature, it has been characterized by X–ray diffraction, IR spectral analysis and UV–vis spectroscopy. The natural elements are detected by the EDX on a scanning electron microscope. The thermal analysis shows that the dehydration of the compound occurs in agreement with the structural features. The temperature dependence of the molar magnetic susceptibility, χM, was measured on a polycristalline sample in the temperature range 5-300 K using a SQUID magnetometer. The structure was determined by X-ray diffraction on single crystal. This salt crystallizes in the triclinic space group P-1 with a = 5.241(1) Å, b = 7.362(1) Å, c = 9.268(1) Å, α = 109.15(2)°, β = 104.39(3)°, γ = 93.15(1)°, V = 323.6(3) Å3 and Z = 2. The crystal structure was determined and refined to R = 0.021 and wR = 0.057 using 1881 independent reflections. The cohesion of structure is only assured by strong intermolecular hydrogen bond O – H …O so forming a three dimensional network.

J. Abdelhak, S. Namouchi Cherni, M.F. Zid, A. Driss

hybrid complex, malonate, cobalt, structure

Pages 79-87

Performances des procédés membranaires pour le traitement d’un jus de cuisson de thon

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Tuna cooking juices have a high level of polluting load (Chemical Oxygen demand- COD- 19 g.L-1) and have to be treated before being rejected in the environment. These juices seem to contain interesting flavor compounds. This recovery would allow the industrialists to diminish the waste water treatment cost and to recover high added value molecules. In this work, a membrane process system consisting in microfiltration (MF) followed by ultrafiltration (UF) or nanofiltration (NF) was used to reduce the pollution load and to concentrate flavor compounds of tuna cooking juice. The first MF step (0,1µm) consisted in clarifying the cooking juice in order to increase fluxes of the following filtrations. In terms of pollution abatement, it can be considered that almost the half of the COD was eliminated by UF (cut-off of the used membrane was 15 kDa). The NF membrane (cut-off: 300 Da) allows an improvement of the quality of the effluent but it is limited for the production of a cleaned water. The polluting load is considerably reduced: COD was reduced by 75 % at the beginning of the concentration (Volumic Reduction Factor VRF = 1) and by 86 % at the end of the concentration (VRF = 5).

A. Ben Nasr, K. Walha, R. Ben Amar, P. Jaouen

Microfiltration, Ultrafiltration, Nanofiltration, Tuna cooking juice, Polluting load

Pages 89-95

Etude structurale de la ZSM-5 échangée au chrome

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Cation exchange of the ZSM-5 by chromium in aqueous phase was studied. The study of the exchange shows that the ratio of exchange depends of the temperature, the nature of the anion of the chromium salt and initial concentration of chromium. The properties of the catalysts were identified by X-ray diffraction, scanning electron microscopy, X-ray fluorescence, TGA and ATD measurements. The results showed that a concentration higher than 0.2M Cr(NO3)3 leads to the presence of the chromium ions at the external surface of the ZSM-5.

Z. Lounis, F. Djafri, A.E.K. Bengueddach

ZSM-5; Ion Exchange; Chromium Catalysts; Bifunctional Catalysts. Redox zeolites

Pages 97-103

Isolation and structure elucidation of a novel alkaloid from Phoenix canariensis(c.) Palm tree

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A new crystalline alkaloid was isolated from the stone fruits acetone extract of Phoenix canariensis (C.) palm tree (canary island date palm). Its structure elucidation was established after X-Ray analysis.

S. Hammami, H. Jarraya, S. Ben Salem, B. Hamdi, A. Ben Salah, P. Devi, A. Nefzi, Z. Mighri

Phoenix canariensis (C.), new alkaloid, 1 and 2D NMR experiments, X-Ray diffraction

Pages 105-108

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