The condensation of aldehydes, β-ketoesters and urea catalyzed by ammonium chloride or montmorillonite KSF without solvent results dihydropyrimidinones. Under ultrasonic irradiation at room temperature, Biginelli products were obtained in higher yields with shorter reaction time.
H. Slimi, Y. Moussaoui, R. Ben Salem
dihydropyrimidinones, ammonium chloride, montmorillonite KSF, ultrasonic irradiation
The reactivity of benzoxazol-2-cyanométhyle 1 has been studied by the reaction with thioisocyanates and chloro-acetonitrile to access thioamides 2, benzoxazolylcyanothioacétonitrile 3 and thiophènes 4.
C. Youssef, H. Ben Ammar, M.L. Efrit, A. Ben Akacha, R. Ben Salem
Benzoxazole-2-cyanométhyle, thioisocyanate, thiophènes, thioamides
A novel, environmentally eco-friendly and high yielding method for the preparation of furfurylamine by one-pot reductive amination of furfural is reported. The reaction is carried out using hydroxylammonium chloride as amination agent and cheap zinc powder as reducer in the presence of zinc chloride and ammonium chloride. This practical procedure has been carried out in water and in neat conditions.
M.A. Ayedi, Y. Le Bigot, H. Ammar, S. Abid, R. El Gharbi, M. Delmas
Renewable resources, furfurylamine, sustainable chemistry, zinc, reduction
The condensation of phosphonoacetonitriles with isothiocyanates performed in tetrahydrofurane, in the presence of potassium tert-butoxide, leads to a potassium thiolate intermediate. This last one reacts in situ with brominated derivatives to give some phosphonylated thiazolines. The identification of all the synthesized products was made by IR and NMR (1H, 13C, 31P) spectroscopies.
I. Jalloul, M.L. Efrit, A. Ben Akacha
Phosphonoacetonitrile, isothiocyanate, cyanothioacetamide phosphonyle, thiazoline, thiazolidinone
The photocatalytic degradation of the mono azo dye Reactive Yellow 23 was investigated in aqueous solutions containing TiO2 suspension as photocatalyst . Results showed that adsorption played an important role in the photocatalytic degradation rate. By comparing the disappearance of RY23 followed by HPLC-DAD (high performance liquid chromatography-diode array detector) and the bleaching of the solution followed by UV-Vis spectrometry (wavelength of analysis = 430 nm), two different kinetics were found proving that some of the intermediate products were still colored. This was confirmed using HPLC-DAD and HPLC-MS (high performance liquid chromatography- mass spectrometry) analysis. The degradation of RY23 should lead to the formation of carboxylic acids (formic, acetic and oxalic). The decrease of Total Organic Carbon (TOC) in dye solution was measured to monitor the dye mineralization process. Major identified intermediates are hydroxylated derivatives. The Langmuir kinetic treatment was chosen because it has already been successfully used to describe solid-liquid reactions of photocatalytic degradation.
I. Bouzaida, C. Ferronato, J.M. Chovelon, M.E.B. Rammah, J.M. Herrmann
Emulsions of the oil-in water type were prepared by the method of "spontaneous emulsification". The oil phase is composed of polymethylhydrosiloxane (PMHS) grafted with cyclodextrins at varying degree of substitution relative to hydrosilane groups: 20% (PMHSCD20), 30% (PMHSCD30) and 40% (PMHSCD40). The cyclodextrin was incorporated for its power to solubilize sparingly soluble compounds in water. The stability of emulsions was monitored by measuring the size distribution of particles in suspension over time. The addition of nonionic surfactants has significantly improved the stability of the preparations. A comparative study of the stability over time has been developed for different preparations depending on the nature of the oil PMHSCDx (x = 20, 30 or 40) and various nonionic surfactants. The best system, in terms of stability, is obtained with PMHSCD20 and the surfactant Pluronic® F127, which remained stable for four months at room temperature.
A. Noomen, S. Hbaieb, Y. Chevalier, R. Kalfat
emulsion, stability, cyclodextrin, poly(hydromethylsiloxane), surfactant
The present work consists in the optimization of some key factors affecting the fermentation of the molasse of sugar cane, the aim of the work is the valorization of this "waste" by bioconversion of its sugars into citric acid. This research of the optimal conditions was supported by several series of experiments where we have studied, for each of them, the infuence of one given factor (intial composition of saccharose, pH, temperature and delay of the fermentation, inoculum volume, etc.) on the production of citric acid.
R. Kessas, L. Benabdi, H. Bouarfa
citric acid, fermentation, aspegillus niger, molasse, optimization
The essential oils of Astragalus gombo collected from two locations in Tunisia were extracted by hydrodistillation and analysed by gas chromatography coupled with mass spectrometry (GC/MS). Results showed that the essential oil composition of plant collected from Sidi Bouzid was more diversified than oil of plant collected from Sbitla. For both locations, the major compound is the phytol with an amount exceeding 31%. The antioxidant activity of the isolated oils, evaluated by DPPH assay, showed that 50% inhibitrice concentrations were 1.4 ± 0.2 mg/ml and 2.8 ± 0.4 mg/ml respectively for Sidi Bouzid and Sbitla locations. The variation in composition and antioxidant activity of oils can be related to the difference of climatic conditions between plant accessions.
H. Teyeb, O. Houta, W. Douki, M. Neffati
Volatile Compounds, GC/MS, Phytol, Antioxidant activit
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