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, TiO2, Al2O3 and Fe2O3, 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.

Graphical abstractSelective production of 4,4′-diaminostilbene-2,2′-disulfonic acid (DSD) from 4,4′-dinitrostilbene-2,2′-disulfonic acid (DNS) without any olefinic group was reduced feasible by catalytic reduction over supported nano-sized gold catalysts with different hydrogen resources, which uncovers a clean synthetic approach for useful aromatic sulfonic stilbene.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Gold nanoparticles with similar average diameters were supported on three metal oxides. ► H2, CO, and HCOONa were used as clean reductants. ► Good selectivity (>94%) between nitro and olefinic group reduction was obtained. ► The catalytic activity can be restored by calcination at 400 °C.