Sulfonated rice husk ash (RHA-SO3H): A highly powerful and efficient solid acid catalyst for the chemoselective preparation and deprotection of 1,1-diacetates

• Rice husk ash (RHA), an agricultural by-product, contains over 80% of silica.
• Sulfonated rice husk ash (RHA-SO3H) was prepared and characterized successfully.
• Very efficient catalyst for preparation and deprotection of 1,1-diacetates
• The catalyst is reusable up to 5 times without any decrease in its activity.

Rice husk ash (RHA), as a source of amorphous silica, was treated with chlorosulfonic acid and sulfonated rice husk ash (RHA-SO3H) as a highly powerful solid acid catalyst was obtained and characterized with a variety of techniques including IR, TGA, SEM, XRD, pH analysis, Hammett acidity function and BET method. This solid acid showed excellent catalytic activity for the protection and deprotection of aldehydes with Ac2O at room temperature under solvent free conditions. The procedure gave the products in excellent yields in very short reaction times and good to high yields. Also this catalyst can be reused for several times without loss of its catalytic activity.

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