Synthesis Procedure Optimization and Characterization of Sulfated Tungstate as a Heterogeneous Catalyst

Development of green catalysts and catalytic reactions are the key demands for green chemistry and sustainability [1]. Sulfated tungstate is green catalyst and was demonstrated its effectiveness as catalyst in amidation, Ritter, Biginelli, and Strecker reactions [2]. Taguchi statistical experimental design has been widely employed in various chemical optimization procedures [3]. Sulfated tungstate was prepared via addition of anhydrous sodium tungstate to a stirred solution of chlorosulfonic acid at 0-5°C. The experimental process parameters for the synthesis of sulfated tungstate were optimized by the aid of Taguchi robust design using an OA9 as orthogonal array design. The studied variables in this investigation were mole ratio of reagents, reaction time, temperature and solvent type. The morphology and chemical composition of the prepared catalyst is well characterized by TGA, X-ray diffraction, SEM and FT-IR spectroscopy We have prepared sulfated tungstate as a stable, cost-effective and reusable solid inorganic acid catalyst useful for nitrone synthesis. The main parameters of the synthesis procedure were optimized by Taguchi statistical experiment design to obtain high yield and minimum particle size of sulfated tungstate.Catalytic activity of sulfated tungstate among the other solid acid catalysts for the preparation of the nitrones was evaluated..