JOURNAL of the Tunisian Chemical Society

serving the Research, the Education and the Industry

Diels-Alder reaction of diactivated dissymetrical cyclopropenes

Written by sctunisie no comments

The addition (4 + 2) of cyclopropenes derived, by photolisis, from pyrazolenines having in position C4 and C5 electroattractive substitutes, is easily achieved on dienes-1,3. They are concerted reactions which are sensitive to steric effects; the Diels-Alder products obtained in this way therefore present a great stereoselectivity.

A. Khemiss, M. Franck-Neumann

Pages 3-9

Perchloric acid effect on the extraction of uranyl nitrate by TBP in CCl4

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Perchloric acid solutions (from 0 to 10 M) were added into nitric aqueous solutions (0-3 M) of uranyl nitrate (roughly 0,1 M). Then Uranium was extracted by 30% TBP in CCl4. These additions yield to a very large increase of the distribution coefficient for uranium. HClO4 "synergic effect" on the extraction of uranium is discussed on the basis of the study of the uranyl ion behaviour in the nitro-perchloric aqueous medium.

O. Benali-Baitich

Pages 33-38

Factorial design optimisation of magnesium amount in wet process phosphoric acid

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By using a 23 factorial design, we have determined the effect of three variables on both the amount of magnesium precipitation in phosphoric acid and the amount of P2O5 losses. While NH4+ appeared to control the form of magnesium precipitate, Al3- and F- appeared to have the greatest effect on the amount of magnesium precipitation.

M. Feki, M, Chaabouni, H.F. Ayedi

Pages 39-48

Apatitic tricalcium phosphate-cadmium carbonate mixture: Its behaviour on heating with and without air

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We have prepared a cadmiocalcium OH Ap by heating the equimolar mixture of cadmium carbonate and apatitic tricalcium orthophosphate at different temperatures. Then the mixture was analysed by X-Ray, IR and TGA. Results showed that the structure and stability of the obtained cadminocalcium OH Ap depend on the preparation atmosphere.

M. Farhat, A. Hamad, S. Chemlal

Pages 49-56

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