Metal supported and metal ion exchanged catalysts from palygorskite for acetylation reaction

Abstract

Efficient solid acid catalysts from palygorskite have been developed by three modification methods, viz., acid activation, metal salt support (with FeCl₃, MnCl₂, CoCl₂, SnCl₂, ZnCl₂ and AlCl₃) and metal ion exchange (exchange with Fe³⁺, Mn^2+, Co²⁺, Sn²⁺, Zn²⁺ and Al³⁺) for acetylation reaction in the liquid phase. The prepared catalysts are characterized by XRD, SEM, FTIR, NH₃-TPD, cation exchange capacity, and BET surface area, and their catalytic activity tested by acetylation of primary and secondary alcohols using acetic acid. The modified palygorskites are found to be efficient catalysts for acetylation of alcohols with no loss of catalytic activity even after four cycles. The iron exchanged palygorskite is found to be most active.