Some aspects of a new method of activation (chemistry in water) are considered. The Diels-Alder reaction is differently affected according to its electronic character (normal, neutral and inverse). The results are compared with the corresponding yields obtained in traditional organic solvents and those derived from catalytic activation by solutions of lithium perchlorate solution in diethyl ether.
N. Habaieb, R. Ben Salem
Hydrophobic effects, Diels-Alder Reactions, Density of cohesion energy
All - furanic polyamides based on a difuranic diacid chloride and various difuranic diamines were prepared by solution and interfacial polycondensation. Regular linear macromolecular structures were thus obtained with reasonably high inherent viscosities. The properties of these materials (glass transition, thermal stability, surface energy) were also examined. Model compounds were prepared in order to facilitate the synthesis and the characterization of the polymers.
A.S. Gharbi, A. Gandini
polyamides, furanic polymers, polycondensation, difunctional furan monomers
The condensation of tétraéthyl orthocarbonate with N1-tosylamidrazones in the presence of acetic acid gives 1,2,4-triazoles with good yields. In basic medium, the reaction of a variety of N1-tosylamidrazones with α-bromoesters gives 1,2,4-triazin-6-ones.
H. Chouaieb, M. Ben Mosbah, M. Kossentini, M. Salem
N1-tosylamidrazones, 1,2,4-triazoles, 1,2,4-triazin-6-ones
In this investigation, different methods for the extraction and the purification of phenolic compounds from the olive mill wastewaters (OMW) were used. Consequently, seven phenolic monomers were isolated at pure grade. By means of spectroscopic methods (IR, UV, MS, 1H NMR, HPLC-UV and HPLC-MS), their structures were established as tyrosol, hydroxytyrosol, caffeic acid, protocatechuic acid, para-coumaric acid, apigenin and luteolin. The antiradical activity of the purified phenolic compounds was evaluated by measuring the radical scavenging effect on 1.1-diphenyl 2-picrylhydrazyl (DPPH). Result showed that hydroxytyrosol presented the highest DPPH radical scavenging effect. The antioxidative activity of the isolated compounds was evaluated using a coupled oxidation of β-carotene-linoleic acid method. The antioxidant potency of the various tested polyphenols was in the following decreasing order: hydroxytyrosol > caffeic acid> protocatechuic acid > para-coumane acid > tyrosol.
N. Allouche, S. Sayadi, M. Damak
olive mill wastewaters, polyphenols, isolation, antioxidants, β-carotene, 1.1-diphenyl 2-picrylhydrazyl
Etude par HPLC et spectrophotométrie UV du mécanisme d’hydrolyse du Baycarb en milieu aqueux
N. Ben Hamida, M. Smaali, S. Sabbah
Electrocoagulation treatment of tannery wastewater
N. Bellakhal, J.L. Brisset, M. Dachraoui
Simulation et analyse exergétique d’une unité industrielle de refroidissement des gaz de pétrole
N. Hajji, A. Rekik, M.R. Jeday
Antipyrine release from dosage forms with an eudragit-RL matrix
Z. Elbahri, N. Chafi, A. Mesli