The 2-fluorotosylates react with organomagnesium compounds and lead to the products where OTs is substituted by organomagnesium alkyl group. When the fluorine atom of 2-fluorotosylates is benzylic, elimination of FOTs is observed. In the case of cyanide ion as reagent, the formation of dinitriles (substitution of F and OTs by C≡N) or unsaturated nitriles (substitution of OTs and elimination of HF) is observed. Methanolysis of unsaturated nitriles occurs when the reaction is carried out in methanol.
A. Hedhli, A. Baklouti
Xylene reflux heating of equimolecular mixture of N-acylimidates and orthoaminobenzophenones (or 1-aminoanthraquinone) leads to the corresponding N-acylimidines. The latters can not be isolated but they cyclize, by elimination of carboxylic acid molecule, thus giving quinazolic derivatives in good yields.
M.T. Kaddachi, N. M'rabet, B. Baccar
Cyclic and acyclic enamines of pyrrolidine react with imidate 2 and α,β-insaturated orthoesters 3 to give 3-(2-oxoalkyl or oxocycloalkyl) propioimidates 4 and orthopropioimidates 5 respectively. The yields range from 50 to 70 %. The structure of these fonctionalized ketones is confirmed by IR and NMR spectroscopy.
A. Hafidh, M.L. El Efrit, H. Zantour, B. Baccar
Artificial ionophores interest in comprehension of mode transport of ions in natural medium induced us to use dibenzo-18-crown-6 as ionophore and to use its complexation by ammonium ions as simple models of amino-acids. A series of non commercial picrates of aromatic amines was prepared and characterized by elemental analysis and by spectroscopy. Picrates are afterwards complexed by the benzenic crown using one Pedersen's modified method. We have synthesized and characterized new stable crystalline complexes for a next structural study.
Z. Ben Rayana-Jomaa, Y. Besace, y. Jaouen, F. Meganem, T. Tlili
Silicium gels doped with cobalt(II) are prepared by a sol-gel process. Starting materials, Si(OCH3)4 and COCl2.6H2O, are dissolved in CH3OH in presence of HCL. Influence of several parameters on the transparency, monolithicity and color of gels is studied. Drying gels at room temperature leads to various colored glasses. I.R. studies show that Co(II) ions are not engaged in the Si-O-Si network, but keep outside this network in complexed forms with water molecules and chloride ions. This result is in agreement with the migration experiment 95% of Co(II) ions are left off the prepared materials when these are brought in contact with water or methanol.
F. Touati, N. Gharbi
After the first step of characterization of surface of the silicas chosen as solid supports of the interface of polymer/solid, the 1H NMR technique is used to study behavior of chains. It shows the influence notably of surface nature on the conformation of grafted macromolecules. In fact, in case of precipitation silica, the chains adopt disordered conformations, whereas, in the case of pyrogenic silicas, they form a uniform layer. These behaviors are pointed out by 13C NMR high resolution solid state techniques.
This paper presents the understanding of an electrochemical conical fixed bed reactor. The assumed chemical model has been cooper deposition from diluted solutions in (1 N) H2SO4. In this work a special emphasis is placed on the specific features of this type of reactor. The numerical solution of the differential equations, obtained from the mass and charge balances, provides us with the knowledge of concentration and potential distribution within the porous bed and permits determination of a reactor design diagram for a both cases of upward (cathode towards anode) and downward (anode towards cathode) percolation.
M. Benzina, A. Ratel, G. Lacoste
In this work we present the choice and acquisition of thermodynamic data of the H2O-MgCl2-LiCl ternary system in order to study the possibility of its utilisation in absorption cycles. The results are shown in tables and/or in diagramms. Analysis of these results shows that this system has a heat pump effect similar to the systems H2O-CaCl2-LiCI, H2O-MgCl2.6H2O-LiCl and H2O-LiBr in the following salts mass composition and temperature ranges: 0.20 ≤ x ≤ 0.50 and 60 ≤ θ ≤ 150°C respectively.
B. Chaouachi, T. Khir, A. Ben Brahim
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