Introduction of sulfonated bamboo (bamboo-SO3H) as a new catalyst for the facile synthesis of bis(indolyl)methanes

Bamboo is one of the important biopolymers which is used in chemistry. In this work, for the first time, a solid acid catalyst from bamboo was prepared from the reaction of sawdust bamboo and chlorosulfonic acid. Relevant properties of catalyst were investigated by FT-IR, XRD, SEM and TGA. The sulfonated bamboo (bamboo-SO3H) with several acid functional groups was utilized as highly efficient, heterogeneous and reusable catalyst for synthesis of bis(indolyl)methanes in short reaction times with excellent yields. Also, the novel solid acid catalyst was reused without any appreciable loss in activity.