Efficient Hydration of Nitriles to Amides in Water, Catalyzed by Ruthenium Hydroxide Supported on Alumina

Abstract

Eine Vielzahl von Amiden ist durch Hydratisierung der entsprechenden Nitrile in Wasser in Gegenwart des Ruthenium‐Trägerkatalysators Ru(OH)x/Al2O3 in ausgezeichneter Ausbeute (>99 %) zugänglich [Gl. (1)]. Beispielsweise gelang die industriell wichtige Umsetzung von Acrylnitril zu Acrylamid quantitativ und mit über 99 % Selektivität. Der Katalysator kann bei gleichbleibender katalytischer Aktivität und Selektivität wiederverwendet werden.

Selective Ruthenium‐Catalyzed Hydration of Nitriles to Amides in Pure Aqueous Medium Under Neutral Conditions

“…Such a TOF value has never been reached in aqueous media under neutral conditions. [14][15][16][17][18][19][20] In summary, a novel catalytic system for the selective hydration of organonitriles to amides in aqueous media and under neutral conditions, namely […”

“…In contrast to these catalytic processes performed in organic solvents, and despite the growing interest to develop environmentally benign and safety processes, metal catalysts able to promote such a transformation in pure aqueous media are much scarcer (water is one of the best choices to replace organic solvents because of its low cost, availability, and nontoxic nature). [12,13] Moreover, the practical application of these homogeneous catalysts, including rhodium, [14] palladium, [15] iridium, [16] molibdenum, [17] nickel, [18] and zinc [19] complexes, [20] shows serious drawbacks mainly due to their low activities and very limited scope of the substrates.…”

Environmentally Friendly Synthesis of Amide by Metal-catalyzed Nitrile Hydration in Aqueous Medium

“…In the following step hydroxide group attacks on nitrile attached carbon intramolecular, to give ruthenium iminolate (II) or ruthenium 2-amideate (III) species (Step II). In the third step, amide with the hydroxide ruthenium is formed by the ligand exchange between the species (II) or (III) and water [23].…”

Ruthenium-Catalyzed Amide-Bond Formation

“…A benchmark in the field was described by Mizuno and co-workers in 2004 employing ruthenium hydroxide supported on alumina (Ru(OH) x /Al 2 O 3 ) as catalyst [60]. This system was able to operate directly in water, showed a great substrate scope, and led to TOF and TON values of up to 13 h -1 and 234, respectively, at 140 ºC.…”