One-pot synthesis of 1-acetylpyrene over supported phosphotungstic heteropoly acid catalysts

Phosphotungstic heteropoly acid (PW) supported on various oxides (SiO2, TiO2, K-10 montmorillonite and c-Al2O3) were synthesized and used as catalysts for Friedel-Crafts acylation of pyrene with acetic anhydride to 1-acetylpyrene for the first time. The as-prepared catalysts were characterized by specific surface area measurement, X-ray diffraction, infrared spectroscopy, and temperature programmed desorption of ammonia. SiO2-supported phosphotungstic heteropoly acid (PW/SiO2 ,4 0 wt%) was found to be the most active catalyst in the acylation giving 91.8 % yield and 100 % selectivity for 1-acetylpyrene at reaction temperature of 60 C under ambient pressure. The effect of PW Loading, PW/SiO2 amount, molar ratio of reactants, reaction temper- ature and reaction time on the catalytic acylation reaction were studied in detail to optimize the process parameters. The reusability of the PW/SiO2 catalyst was appraised, and the possible pathway for the production of the Friedel-Crafts acylation of pyrene with acetic anhydride catalyzed by phosphotungstic heteropoly acid was also discussed briefly.