A heterogeneous solid acid catalyst, sulfonic acid supported on pericarp-pomegranate (sulfonic acid@PP) is prepared with green an eco-friendly approach. The prepared sulfonic acid@PP catalyst was extensively characterized by IR, FE-SEM, EDX and TGA techniques. The efficiency of the catalyst has been investigated for the synthesis of bis(indolyl)alkanes by electrophilic substitution reaction of indoles with carbonyl compounds in ethanol at 80 oC. Easy recovery by simple filtration and at least three times reusability without significant loss in the yield of the desired product are conspicuous features of the reported catalyst. In addition, the notable features of this protocol are high conversions, shorter reaction times, cleaner reaction profile, simple experimental and work-up procedure.
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