Farhad Shirini - Department of Chemistry, College of Sciences, Guilan University, Rasht, ۴۱۳۳۵-۱۹۱۴۱, Iran
Mohadeseh Seddighi

Rice husk ash (RHA), as a source of amorphous silica, was treated with chlorosulfonic acid and sulfonated rice husk ash (RHA-SO3H) as a highlypowerful solid acid catalyst was obtained and characterized with a variety of techniques including IR, TGA, SEM, XRD, pH analysis, Hammett acidityfunction 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. Theprocedure 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.