The Preparation of amides is an important transformation from both academic and industrial points of view. Amides not only constitute versatile building blocks in synthetic organic chemistry, but also exhibit a wide range of industrial applications and pharmacological interest [1]. Most of the known synthetic transformations leading to amides are based on the reaction between an activated carboxylic acid and an amine or ammonia. Nitriles are intrinsically more reactive than carboxylic acids and direct conversion of nitriles to primary amides are more interesting in organic synthesis. However, a base-catalyzed reaction leads to a carboxylate salt, because the second step of the hydrolysis is faster than the first one, and the reaction thus proceeds to the final hydration product rather than stopping at the amide stage. Although in strong acidic solutions it can be possible to obtain amides, it is then necessary to have careful control of the temperature and of the ratio of reagents in order to avoid the formation of polymers which is promoted by the exothermic character of the hydrolysis [2]. Several syntheses of primary amides from nitriles have been reported using NaBO3/MW [3], ZnCl2/MW [4], Co(III) complex, ruthenium complex/sealed tube, TMSCl, KOTMS, and nitrile hydratase. However, most of the reported methods have not been proven in general and practical in scope because of harsh condition or expensive catalyst. In this paper we introduced natural kaolin supported sulfuric acid as an efficient catalyst for the selective hydrolysis of nitriles to primary amides in aqueous conditions.

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