GREEN CATALYTIC PROCESS FOR ASPIRIN SYNTHESIS USING FLY ASH AS HETEROGENEOUS SOLID ACID CATALYST

摘要

This invention relates to a catalytic process for the preparation of acetyl salicylic acid, Aspirin using nano-crystalline activated fly ash solid acid catalyst having crystallite size in the range of 13-28 nm,BET surface area in the range of 80-120m2g-1" pore volume 0.08-0.2 cm3g-1" pore size 35-60 A° comprising of Chemical activation of raw fly ash with sulfuric acid (with different fly ash/sulfuric acid ratio) at boiling temperature; Ageing the slurry at 110°C for 5 days under stirring afterwards refluxing the slurry at 110°C for 4h,Washing the slurry with water and drying at 110°C for 24 h followed by calcinations at temperature 600°C for 4 h, reacting salicylic acid with acetic anhydride in presence of fly ash catalyst in a solvent free medium, maintaining the substrate to catalyst ratio 5-20 weight percent; maintaining the temperature of the reaction in the range of 90 to 120° at atmospheric pressure for a period selected from 30 to 120 min; separating the product aspirin (acetyl salicylic acid) from the reaction mixture by known filtration techniques; washing the catalyst with acetone to remove adhering materials and drying the catalyst at 110°C followed by air calcinations at 450°C for a period between 2-4h.