Phosphoric acid functionalized graphene oxide: a highly dispersible carbon-based nanocatalyst for the green synthesis of bio-active pyrazoles

Abstract

Carbon-based catalysts are gained significant interest for improving a number of catalytic processes due to their unique set of benefits. However, a few of such catalysts are proper for synthesis of organic compounds in water. Therefore, there is a strong need for developing water-tolerant and dispersible catalysts. Here, we demonstrate a simple and efficient method for the preparation of highly dispersible phosphonic acid functionalized carbocatalyst. The applied functionalization method was flexible in controlling the functionalization level. The prepared nanocatalyst exhibited superior catalytic performance toward multicomponent synthesis of pyrano[2,3-c]pyrazole, with 80-90% yield within 15 min in water. Moreover, this water-tolerant solid acid. catalyst could be simply retrieved and after 6 successive cycles of reactions, the reaction time and yield still keeps within the same level.