Synthesis of sulfonated carbon-based solid acid as a novel and efficient Nanocatalyst for the synthesis of 2-amino-7-hydroxy-4H-chromene

A novel carbon-based solid-acid nanocatalyst (SCP-SO3H) was simply prepared for the first time by the the one-step hydrothermal reaction of Starch as carbohydrate source and p-toluenesulfonic acid as sulfonating in the presence of citric acid.The catalytic activities of SCP-SO3H as efficient and reusable catalyst were investigated by the condensation reaction of aldehyde, malononitrile and resorcinol for the synthesis of 2-amino-7-hydroxy-4H-chromene in water as a green solvent at 70 ºC in excellent yields. The prepared catalytic system was characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy.The catalyst could be quantitatively recovered from the reaction mixture by simple filtration and reused at least three times with almost consistent acticity.