P(hema)-so 3 h catalyst: Preparation, characterization and its catalytic activity in ritter reaction

Abstract

In this study, poly(hydroxyethyl methacrylate) [P(HEMA)] microsphere-supported sulfuric acid [P(HEMA)-SO3H] was prepared as a novel heterogenous solid acid catalyst and its catalytic activity was investigated in the synthesis of amides via Ritter reaction. The P(HEMA) microspheres were synthesized via suspension polymerization and characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Brunauer, Emmett and Teller surface area and energy dispersive X-ray (EDX) analyses. The specific surface area and the pore volume of the microspheres were determined as 33.80 m(2)/g and 1.490 cm(3)/g, respectively. The pore size was in the range of 9.18-122.59 A degrees. The specific surface area of P(HEMA)-SO3H catalyst was 26.24 m(2)/g decreasing after modification with sulfo groups. FTIR, SEM and EDX analyses demonstrated that P(HEMA) microspheres were successfully modified with sulfo groups. The acidity of P(HEMA)-SO3H catalyst was determined as to 7.48 +/- 0.16 mmol H+/g P(HEMA)-SO3H catalyst by titration with standardized NaOH solution. The catalyst was then successfully applied in the Ritter reaction to prepare a series of different amides in high to excellent yields. The P(HEMA)-SO3H catalyst was recovered and reused four times without a significant decrease in the catalytic activity. The other advantages of this novel catalyst include excellent yield, short reaction time and solvent-free conditions.[GRAPHICS]