so3h-functionalized magnetic graphene oxide: green and recyclable heterogeneous catalyst for n-formylation of amines

Design and use of environmentally friendly catalysts with outstanding features such as high activity, high surface-to-volume ratio, excellent selectivity, high durability, low cost of preparation and good recycling is an urgent need [1]. one of the major environmental challenges that scientists have been focusing on is the development of a broad range of selective, cost-effective and efficient recyclable catalyst systems such as magnetic nanocatalysts and functionalized nanocatalysts, and their application in a wide range of organic and industrial transformation [2-3]. in recent decades, due to the development of catalytic chemical technology, organocatalysts have attracted much attention [4]. in this study, sor3rh-functionalized magnetic graphene oxide was used as a metal-free bronsted solid acid catalyst for the catalysis of n-formylation condensation of various amines for green synthesis of formamides (scheme 1). this catalyst showed excellent performance with high yields for various amines up to 95% in 2-8 h at 50 p o pc. the advantages of this heterogeneous catalyst can be easy to use, easy recovery, high recyclability, low amount catalyst and bifunctional role of the catalyst.