Younes Abrouki

A natural phosphate and doped-catalyzed Michael addition of mercaptans to α, β-unsaturated carbonyl compounds

The natural phosphate and doped by potassium fluoride catalyzed Michael addition of mercaptans to chalone derivatives with high yields in few minutes and under mild reaction conditions. Products of undesirable side reactions resulting from 1,2-addition, polymerisation and bis-addition are not observed. The work-up procedure is simplified by simple filtration with the use of natural phosphate alone or doped with potassium fluoride.

Fluorapatite: efficient catalyst for the Michael addition

A Michael addition assisted by fluorapatite in heterogeneous media is described. Reaction between mercaptans and chalcone derivatives was studied at room temperature in methanol as solvent. By-products of usual undesirable reactions in Michael addition such as 1,2-addition, bis-addition and polymerisation are not observed. The yields obtained are good to excellent.

Na2CaP2O7, a new catalyst for Michael addition

The synthetic diphosphate Na2CaP2O7 is a new basic catalyst for Michael addition of mercaptans to chalcone derivatives with high yields in a few minutes and mild reaction conditions. Products of undesirable side reactions resulting from 1,2-addition, polymerisation and bis-addition are not observed.

Colour and COD removal of disperse dye solution by a novel coagulant: Application of statistical design for the optimization and regression analysis

The investigation presented here focussed on the steel industrial wastewater (SIWW) FeCl(3) rich as an original coagulant to remove the synthetic textile wastewater. Response surface methodology was used to study the cumulative effect of the various parameters namely, coagulant dosage, initial pH of dye solution, dye concentration and to optimize the process conditions for the decolourization and COD reduction of disperse blue 79 solution. For obtaining the mutual interaction between the variables and optimizing these variables, a 2(3) full factorial central composite rotatable design using response surface methodology was employed. The efficiencies of decolourization and COD reduction for disperse blue 79 solution were accomplished at optimum conditions as 99% and 94%, respectively.

New eco-friendly animal bone meal catalysts for preparation of chalcones and aza-Michael adducts

Two efficient reactions were successfully carried out using Animal Bone Meal (ABM) and potassium fluoride or sodium nitrate doped ABMs as new heterogeneous catalysts under very mild conditions. After preparation and characterization of the catalysts, we first report their use in a simple and convenient synthesis of various chalcones by Claisen–Schmidt condensation and then in an aza-Michael addition involving several synthesized chalcones with aromatic amines. All the reactions were carried out at room temperature in methanol; the chalcone synthesis was also achieved in water environment under microwave irradiation. Doping ABM enhances the rate and yield at each reaction. Catalytic activities are discussed and the ability to re-use the ABM is demonstrated.ResultsFor Claisen–Schmidt the use of ABM alone, yields never exceeded 17%. In each entry, KF/ABM and NaNO3/ABM (79-97%) gave higher yields than using ABM alone under thermic condition. Also the reaction proceeded under microwave irradiation in good yields (72-94% for KF/ABM and 81-97% for NaNO3/ABM) and high purity. For aza-Michael addition the use of ABM doped with KF or NaNO3 increased the catalytic activity remarkably. The very high yields could be noted (84-95% for KF/ABM and 81-94% for NaNO3/ABM).ConclusionThe present method is an efficient and selective procedure for the synthesis of chalcones an aza-Michael adducts. The ABM and doped ABMs are a new, inexpensive and attractive solid supports which can contribute to the development of catalytic processes and reduced environmental problems.

Optimization and Modeling of Decolorization and COD Reduction of Reactive Dye Solutions by Coagulation Processes with SIWW’s Coagulant

Abstract Textile dyeing processes are among the most environmentally unfriendly industrial processes because they produce colored wastewaters that are heavily polluted with synthetic dyes. The investigation presented here focuses on the steel industrial wastewater (SIWW) FeCl3 rich as an original coagulant to remove the synthetic textile wastewater. The effects of relevant parameters—namely; coagulant dosage, initial pH of reactive dye solutions, and dye concentration—have been investigated with regard to decolorization and COD reduction by using response surface methodology (RSM). These experiments were carried out as a central composite design (CCD) consisting of 16 experiments determined by the 23 full factorial designs with six axial points and two center points. A model has been obtained for decolorization, COD reduction, and relevant parameters by means of variance analysis and the model obtained was optimized. The efficiencies of decolorization and COD reduction for Reactive Orange 16 were accomplished under optimum conditions as 98% and 90%, respectively.

Natural phosphate and potassium fluoride doped natural phosphate as new catalysts for the Vilsmeir-Haack type reaction

The catalytic activity of the inexpensive natural- or potassium fluoride doped phosphates as bases was evaluated in a Vilsmeier–Haack type reaction. High efficiency, in term of chemical yields and reaction rates was found in the preparation of 2-chlor-3-cyanopyridines starting from 2-propylidene-malonitriles.

Experimental Design-Based Response Surface Methodology Optimization for Synthesis of β-Mercapto Carbonyl Derivatives as Antimycobacterial Drugs Catalyzed by Calcium Pyrophosphate

A simple protocol for the efficient preparation of β-mercapto carbonyl derivatives as antimycobacterial drugs has been achieved via Thia-Michael reaction between chalcones derivatives and thiols in the presence of calcium pyrophosphate as a heterogeneous catalyst under mild reaction conditions. The central composite design was used to design an experimental program to provide data to model the effects of various factors on reaction yield (Y). The variables chosen were catalyst weight (X 1), reaction time (X 2), and solvent volume (X 3). The mathematical relationship of reaction yield on the three significant independent variables can be approximated by a nonlinear polynomial model. Predicted values were found to be in good agreement with experimental values. The optimum reaction conditions for reaction model (chalcone and thiophenol) obtained by response surface were applied to other substrates. This procedure provides several advantages such as high yield, clean product formation, and short reaction time.