Sulfonic Acid‐Functionalized (Bio)Materials as Catalysts for Efficient Amide Bond Synthesis

Abstract Sulfonic acid carbon‐(bio)based and natural clays‐based catalysts were prepared and investigated for the first time as heterogeneous catalysts for amide bond synthesis by a Ritter reaction. The different SO 3 H‐catalysts were screened using benzyl alcohol and acetonitrile as model substrates, and MWCNT‐CSP revealed to be an efficient catalyst, affording the amide in 75 % yield. The practical utility of the catalysts was demonstrated by a diverse range of amides, obtained from alcohols and nitriles, in moderate to good yields. Biomass derived platform alcohols, such as 5‐HMF and furfuryl alcohol, were also tested as potential building blocks for the synthesis of biopolymers. The SO 3 H‐catalysts revealed to be a highly efficient and environmentally friendly alternative to the conventional acid catalysts commonly used in the Ritter reaction.