Said Boukhris

The synthesis of quinoxaline derivatives were heterogeneously catalyzed by phosphate-based catalyst fertilizers, MAP, DAP, or TSP. The reaction affords the desired products in excellent yields at ambient temperature. A series of studies were conducted to investigate the effect of solvent reaction, its volume, and catalyst amount. A study of the recyclability of catalysts removed from the reaction mixture by simple filtration was also carried out to find that the three phosphate-based catalysts retain their catalytic activities up to six cycles.

A simple and efficient method for the synthesis of quinazolin-4(3H)-one derivatives via condensation of anthranilamide with aromatic aldehyde catalyzed by monoammonium phosphate (MAP), diammonium phosphate (DAP), and triple superphosphate (TSP), were developed. The modification of these three phosphate fertilizers using titanium tetrachloride (TiCl4) has increased their catalytic efficiency. The prepared titanium phosphate (TiP2O7) was characterized using microscopic and spectroscopic methods, namely X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and infrared spectroscopy (IR). The TiP2O7 was applied for the first time as a heterogeneous catalyst in quinazolin-4(3H)-ones synthesis. High yields and short reaction times were observed in the determined optimal condition (solvent nature, volume, and catalyst amount). This study shows that the TiP2O7 presents an exciting catalytic activity and long-term durability compared to those of MAP, DAP, and TSP.

Metallic materials are well known and widely used in various industrial sectors. However, they can be easily corroded in various aggressive environments. The protective action of stainless steel by two organic pyrazole compounds: {1-amino-5,10-dioxo-3-(p-tolyl)-5,10-dihydro-1H-pyrazolo[1,2-b]phthalazine-2-carbonitrile} and {1-amino-3-(2-chlorophenyl)-5,10-dioxo-5,10-dihydro-1H-pyrazolo[1,2-b] phthalazine-2-carbonitrile} in H2SO4 2.0M medium was studied using the electrochemical technics (Electrochemical Impedance Spectroscopy (EIS), potentiodynamic polarization), Scanning Electron Microscopy (SEM) and Energy Dispersion X-ray spectroscopy (EDX). Polarization curves indicate that both compounds act as anodic inhibitors. A suitable equivalent electrical circuit model was used to calculate the impedance parameters. The adsorption study showed that these compounds are adsorbed to the steel surface according to the adsorption isotherm of Langmuir. Effect of temperature was also investigated and activation parameters were evaluated.

This study presents a simple, efficient, and ecological procedure for the synthesis of biscoumarins and 3,4-dihydropyrano[c]chromenes under green conditions using Zn₃(PO₄)₂.4H₂O as a heterogeneous catalyst. In fact, Zn₃(PO₄)₂.4H₂O was prepared for the first time from triple superphosphate fertilizer (TSP) (Ca(H₂PO₄)₂) and zinc sulfate (ZnSO₄). Then, it was characterized by spectroscopic and microscopic technics such as X-ray diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDX). The synthesis derivatives of biscoumarins and dihydropyrano[c]chromenes, in the optimal reaction conditions (nature of the solvent, amount of catalyst and temperature), was performed. The obtained results are excellent in terms of time (15–30 min) and yields (81–87%). Besides, Zn₃(PO₄)_2.4H₂O can be reused at least six times without significant loss of its catalytic activity, because of its long-term durability.