Modified attapulgite: An efficient solid acid catalyst for acetylation of alcohols using acetic acid

Acid treated attapulgites catalyze acetylation of alcohols using acetic acid in excellent yield. Natural attapulgites from different states of India: Gujarat, Andra Pradesh and Karnataka were modified by acid activation to prepare solid acid catalysts. Detailed catalyst characterization was carried out by XRD, chemical analysis, SEM, surface area, cation exchange capacity and acidity measurements. Acetylation of cyclohexanol using acetic acid was selected as the test reaction. Efficiency of these catalysts was compared with the catalyst prepared from the authentic sample (Source Clay Minerals Repository, U.S.A) and also the commercial ones, K-10 and KSF/0. Performance of the indigenous catalysts was found comparable in selectivity and percentage conversion. Acetylation of different primary and secondary alcohols also gave excellent yield. Acetylation over attapulgite using acetic acid is being reported for the first time.

Research Highlights
► Acid modification of natural attapulgite results in excellent solid acid catalysts.
► Modified attapulgite catalyzes acetylation of alcohols using acetic acid.
► Acid activation by 0.7 N HCl has got maximum activity in catalyzing acetylation.