Synthesis and reactivity of 1,2-diazaspiropentanes
Written by sctunisie no commentsNovel heterocycles N,N'-disubstituted 1,2-diazaspiropentane have been synthesised and solvolysed with perchloric acid into N-substitued β-lactame.
T. Tlili
Pages 3-7
Thermal evolution of chromium oxide gels produced by "Sol-Gel" process
Written by sctunisie no comments"Sol-gel" process at room temperature is used to elaborate chronium III gels. The xerogel obtained after drying gel was characterised by different techniques : XR, DTA, TGA, and chromatography. The material was stayed amorphous until 400°C. Above this temperature it cristallizes to α Cr2O3 phase.
N. Gharbi, A. Ghorbel, J. Livage
Pages 9-12
13C N.M.R. studies of substituted purines and oxopurines
Written by sctunisie no comments13C N.M.R. spectra of some trisubstituted N-aminopurines and disubstituted N-amino-oxopurines are reported. Influence of substituents of the 13C chemical shifts of those purine carbons is also reported.
J.M.A. Al Rawi, B. Hajjem, N. Ayed, B. Baccar
Pages 13-17
Reaction of hydrazids, alkyl carbazats and semi-carbazids on hydroximates and synthesis of 4-hydroxy-1,2,4-triazoles, 4-hydroxy-1,2,4-triazolones and 4-phenyl-1,2,4-triazole
Written by sctunisie no commentsHydroximate of type 1 have been shown to react with hydrazids, alkyl carbazat and semi-carbazid to give respectively 4-hydroxy-1,2,4-triazole, 4-hydroxy-1,2,4-triazolone and 4-substituted-1,2,4 triazolone in good yield. The process of the reaction is discussed.
A. Bel Hadj Amor, B. Baccar
Pages 19-26
Role of acetic in elaboration of zirconium gels by hydrolysis of Zr (OPrn)4
Written by sctunisie no commentsSol-gel processing of ZrO2 is performed via hydrolytic polycondensation of zirconium tetrapropoxide Zr(OPr)4 in the presence of acetic acid. The gelation times as well as the aspects of the produced gels are studied as functions of the molecular ratios h = H2O/ Zr(OPr)4 and k = CH3COOH/ Zr(OPr)4. I.R. study shows that molecular precursors of general formula Zr(OPr)x (AC)y are formed in which the bidentate acetates (Ac) replace the OPr groups and are directly bounded to zirconium by both chelation and bridging. Ac ligands exhibit a strong resistance to the action of water and their departure by heating is only possible at temperatures higher than 200°C. Water, indispensable for hydrolysis of Zr(OPr)x (Ac) species, is formed in-situ by action of acetic acid on n-PrOH. Further addition of water isn't necessary.
C. Ben Amara, N. Gharbi, H. Zarrouk
Pages 27-34
Synthesis and spectroscopic analysis of a new perchlorato complexe: Sn (C104)4
Written by sctunisie no commentsA new anhydrous perchorato tin IV complexe Sn(ClO4)4 is synthesised by heating at 100°C under vacuum (ClO2)2 Sn(ClO4)6. The chloryl salt is obtained by reaction of an excess of chloride trioxide Cl2O6 with SnCl4. Infra-red et Raman spectra of Sn(ClO4)4 are interpreted satisfactorily on the basis of a polymeric model containing both monodentate and bridging bidentate perchlorato groups as in Sn(SO3F)4.
M. Fourati, M. Chaabouni
Pages 35-39
Short communication: Micronutrients in maniac: Preliminary results
Written by sctunisie no comments
A preliminary analysis of fatty acids in some varieties of manioc from Congo (Manihot Esculenta Crantz) shows that total amount of these acids is within the range 0.3 to 1.2 %. These acids are principally palmetic, stearic and oleic acids. Linoleic acid is also present among unsaturated acids.
E.B. Dongala, M.G. Maloumbi, C. Badila Samba
Pages 41-43