The reaction of benzyl alcohol, benzyl chloride or dibenzyl ether witch sulfuric acid, tin (IV) chloride or cation exchange resin (in the H from) leads to a polymer. The definition of "protonic" or "carbocationic" acids is proposed. This new formulation agrees with ail the observed results.
T. Mhiri, J.L. Janier Dubry
Pages 3-15
The Zinc, cadmium Lead and copper were determined in the seawater of Tunis South lake. The analytical method used is impulsional anodic stripping voltammetry with a hanging mercury drop electrode.
F. Bazine, M. Dachraoui, H. Latrous
Pages 17-27
The amount of lithium chemically incorporated in the host structure of V5S8 by reaction with n butyllithium is, 1,4 Li/V (C = 370 Ah Kg ). By electrochemical process (galvanostatic technique) only 0,2 Li/V are inserted (C = 56 Ah kg ) The substitution of vanadium by iron retains the structure of V5S8, but the capacity of system decreases with the quantity of iron substituted.
F. Dalard, D. Daroq, A. Sellami
Pages 29-35
The complex permittivity of the compound Ba0,86 Sr0,14 TiO3 polycristalline has been determined in function of the frequency in the range 0,01 - 5 GHz. A phenome non of adsorption - dispersion has been established at 1,9 GHz and interpreted at a preliminary stage.
H. Zangar, M.S. Haouat
Pages 37-42