JOURNAL of the Tunisian Chemical Society

serving the Research, the Education and the Industry

1,2,4,3-triazoles substituted in 1,5 positions

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The derivates of 1,2,4,3-triazaphospholes can exist in several different isomeric forms depending on the type of substitution. Forms 1 and 2 were prepared using methods described in the literature (1) (3) by action of hydrazine on imited where two forms of amidrazones A and B were obtained which react with tris (dimethyl-amino) phosphine to give an important quantity of 1 accompagned by quantity of 2 and some times only 1. In this work, we are describing a new method giving a better quantity of 2 and particulary when the type of substitutions were Ph. Ph. We acced to the diphenyl-1,5 triazaphosphole-1,2,4,3 which coudn't be obtained by Y. Charbonnel methods (1) (3). The 1,5 disubstituted-1,2,4,3-triazaphospholes react with organomagnesium halides like the 2,5 disubstituted homologues. We are giving here the results of this comparative study.

M. Haddad, M.T. Boisdon, J. Barrans

Pages 75-88

Reaction of carboxylic esters and carbonylated derivatives on benzyl hydroximate dilithyated

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Action of the two equivalent of the L.D.A. on ethyl benzylhydroximate leads to the corresponding dilithiohydroximate. The latter reacts with carboxylic esters and carbonated derivatives (aldehydes and ketones) to give after hydrolysis, the hydroxyled hydroximates which are treated with concentrated sulfuric acid, thus they are transformed accordingly into 1,2-oxazoles or 4,5-dihydro 1,2-oxazoles.

H. M’rabet, A. Bel Hadj Amor, B. Baccar

Pages 89-96

Influence of water vapor pressure on cristallization of a sodium magnesium phosphate

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A precipitate phase Na3MgH(PO4)2 was obtained when salt phosphate solution containing magnesium was concentrated under different water pressures. This phase was not effected by the water pressure changes in the range of 0.3-2 atm. However, an important change was observed in the morphology and the crystallinity.

M. Ben Amor, M. Aoun, S.S. Romdhane

Pages 105-112

X-Ray scattering under synchroton radiation for the study of swelling of some clays

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Small angle X-ray scattering under synchrotron radiation is a new method which allows on to calculate for each clay sample, the statistical distribution of the thickness of the layers and the average number of the individual layer which forms a particle. Hectorite, montmorillonite from Wyoming, montmorillonite from Camp Berteaux, nontronite and vermiculite have been studied by this technique. The following results were obtained :

  • Parameters influencing the number of the individual layer and the swelling are the layer charges independently on the nature of the exchangeable cations.
  • Swelling tends to be low in clay with tetrahedrally charged.
  • Interparticle water is three or four times higher than in interlayer water.

F. Turki

Pages 113-124

Liquid-solid transfer coefficient by an electrrochemical technique

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The paper proposes a fonctionnement of a fixed bed electrochemical reactor. The limiting current technique is used to obtain the liquid - solid mass transfer coefficient. The porous electrode is made of copper particles which are percolated by a dilute solution of Cu++ ions in a sulfuric acid medium. We found a correlation between the Reynolds number Re and the Sherwood number Sh : Sh = 2,1 Re0,35 Sc0,33. This correlation is compared with empirical ones obtained by several authors and is in good agreement with them.

M. Benzina. S. Gabsi, G. Lacoste

Pages 125-140

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