JOURNAL of the Tunisian Chemical Society

serving the Research, the Education and the Industry

Utilisation d’α-formyl-α-arylacétonitriles en synthèse hétérocyclique

Written by sctunisie no comments

The condensation of -1,2 and -1,4 binucleophilic compounds with the α-formyl-α-arylacetonitriles constitutes a new route to the synthesis of five and seven membered heterocycles such as aminopyrazoles, aminodiazepines, aminoxazepines and aminothiazepines.

A. Khlifi, M.L. El Efrit, H. Zantour

α-formyl-α-arylacetonitriles. aminopyrazoles, aminodiazepines, aminooxazepines, arninothiazepines

Pages 1-9

Influence of fruit ripening process on the natural antioxidant content of Chemlali olive cultivar

Written by sctunisie no comments

A quantitative study of monomeric phenols and flavonoids based on separation by high performance liquid chromatography (HPLC) was carried out to examine phenolic profile during maturation of chemlali olive cultivar. The extracts were dominated by oleuropein. Its concentration decreases with fruit maturity and is accompanied by the increase of other phenols such as hydroxytyrosol. A weak change in the amounts of tIavonoids and other phenolic monomers was observed. The total phenolic content determined by colorimetric measurement ranges from 6 to 16 g Kg-1 of pyrogallol equivalent. The level of free phenols in the hydrolysate solution after enzymatic and acid hydrolysis was higher than their level in the extracts. The antioxidant capacity of Chemlali olive fruit extract before and after hydrolysis was also investigated. The radical scavenging effect was evaluated using DPPH experiment. An inverse relationship between total phenols and IC50 value during maturation was established. An increase of antioxidant potential after enzymatic and acidic hydrolysis was also observed.

M. Bouaziz, M. Damak, S. Sayadi

Olive, Phenolic compounds, Maturation, Enzymatic hydrolysis, Antioxidant

Pages 11-20

Etude de l’évolution des stérols, des alcools aliphatiques et des pigments de l’huile d’olive au cours du processus de maturation

Written by sctunisie no comments

Olive oil minor compounds have a crucial importance in quality determination. For this reason, the influence of maturity process on the evolution of sterols, aliphatic alcohols and pigments (chlorophylls and carotenes) contents in the oil was studied. Samples have been taken from chemlali variety harvested in Sidi Bouzid region. The gotten results showed a progressive decrease of the chlorophylls, carotens, sterols and aliphatic alcohols C26 and C28 contents during the maturity process. On the other hand, unsaponifiable matter amount was stable during this process. Thus, the best harvesting period is November and December, during this period we can obtain oils with the best quality parameters.

A. Lazzez, M. Cossentini , M. Khlif , B. Karray

olive oil, minor compounds, sterols, aliphatic alcohols, pigments

Pages 21-32

Solvent-free Knœvenagel reaction of malonic acid

Written by sctunisie no comments

Knœvenagel reaction is applied to the condensation of malonic acid with aromatics aldehydes in solvent-free conditions under conventional heating. This solvent-free reaction leads in a single step to corresponding unsaturated diacids, when the basic entities such K2CO3, Na2CO3 KHCO3 and KOH are used. The application of the same reaction with pyridine, piperidine and quinoline, acting as catalysts, leads after decarboxylation, to the insaturated monoacid.

M. Fakhfakh, M. Abid, S. Abid, R. El Gharbi

malonic acid, Knœvenagel​​​​​​​ reaction, solvent-free synthesis

Pages 43-47

Synthesis methodology of substituted tetraphenylborate salts

Written by sctunisie no comments

Tetraphenylborate substituted at the meta, para or 3,5 positions with diaminotriazine groups can be used like charged subunits for the construction of anionic hydrogen-bonded networks by the strategy of molecular tectonics. We have developed a synthesis methodology leading to various substituted tetraphenylborates salts 2, 3 and 4 and to their precursors such as cyanotetraphenylborates 8, 9 and 10 and iodo or bromotetraphenylborates 5, 5a, 6, 6a and 7, 7a mainly used in gravirnetry, which consist in cation separations by selective precipitations.

N. Malek, M. Saied, J.D. Wuest

Gravimetric, synthetic methodology, hydrogen bonding, anionic networks, tetraphenylborates

Pages 55-61

Seasonal variation of the essential oil of Rosmarinus officinalis L.

Written by sctunisie no comments

The essential oil isolated by hydrodistillation from young sprouts of Rosmarinus officinalis L. (Lamiaceae) collected from four natural populations of Tunisia (El Houdh, Chambi, Oueslatia and Zaghouan) at three periods of the year 2000 (February, April, July) have been analyzed by gas chromatograph and gas chromatograph coupled with mass spectrometer. 36 compounds have been isolated with quantitative variations between the various populations examined. 1,8-cineole (31.1-55.4%) was found to be the main component of this oil. Monoterpenes were shown to be the major fraction (91.3-98.8%) and mainly composed of 1,8-cineole, α-pinene, camphene, p-cymene, limonene, α-terpineol, camphor, borneol and bornyl acetate. For all populations, the highest yield of oil was obtained from samples collected in April.

F. Bannour, I. Chéraif, M. El Gazzah, F. Farhat, M. Hammami, R. Chemli

Rosmarinus officinalis, Lamiaceae, Essential oil, 1,8-Cineole

Pages 63-68

Etude de la rétention de la nicotine et des hydrocarbures polyaromatiques sur le filtre de cigarettes imbibé de bleu de méthylène

Written by sctunisie no comments

A study of the retention of polyaromatic hydrocarbons and of the nicotine existing in the smoke of cigarettes has been undertaken. The presence of the methylene blue on the filter makes the rate of the retention bigger. The augmentation of this retention has been interpreted by molecular interaction of the chemical species. The formation of complex has been discussed.

H. Ghabi, N. Gharbi

interaction, methylene blue, nicotine, polyaromatic hydrocarbons complex, UV visible

Pages 69-75

Improvement of textile waste waters treatment by combination of ultrafitration and nanofiltration membraprocesses

Written by sctunisie no comments

The present work deals with the preparation and the characterization of cellulose acetate membranes for the textile water treatment by ultra (UF) and nanofiltration (NF). The evolution of flow was analyzed and treated by a comparative study of the pH and time effects on the performances regeneration of prepared membranes. The carried out study made it possible to follow the pollution indicators during UF-NF. Indeed, we contributed to the elimination of 95% of the CDO. The proportions obtained after treatments are in conformity with the imposed standards.

K. Ksontini, E. Ferjani, M.S. Roudesli

Textile waste water, membrane, cellulose acetate, ultrafiltration, nanofiltration

Pages 77-88

Rss feed of the category