Supported nano-sized gold catalysts for selective reduction of 4,4′-dinitrostilbene-2,2′-disulfonic acid using different reductants

Gold nanoparticles supported on three metal oxides , TiO 2 , Al 2 O 3 and Fe 2 O 3 , were prepared by a modified precipitation-deposition method using urea as an additive. These catalysts were tested in chemoselective reduction of 4,4′-dinitrostilbene-2,2′-disulfonic acid to 4,4′-diaminostilbene-2,2′-disulfonic acid. Three reagents, hydrogen, carbon monoxide , and sodium formate, were employed as reductants . It was found that >94% of the nitrostilbene was transformed into the aminostilbene without the reduction of olefinic group. In addition, these catalysts exhibited stable performance after regeneration by calcination at 400 °C for 5 h. This clean approach provides a promising application for synthesis of amino substituted stilbene sulfonic acid on an industrial scale.