Synthesis and application of gold-carbon hybrids as catalysts for the hydroamination of alkynes

Abstract

Gold-carbon hybrids have been efficiently used as catalysts for the hydroamination of phenylacetylene with aniline. Carbon supports (single-walled and multi-walled carbon nanotubes, graphene oxide, graphite, graphitic cones, nanodiamond, ordered mesoporous carbon, carbon xerogel, carbon black, activated carbon, and laser-ablation produced carbon foam) were homogenously decorated with gold nanoparticles (GNP) synthesized by in situ reduction of chloroauric acid (H[AuCl4]) in water. The performance of carbon materials used as catalytic supports has been here evaluated. The synthesized gold-carbon hybrids worked remarkably well as catalysts for the targeted reaction. Conversion values as high as 79% were achieved by suitably adjusting the gold:carbon support w/w ratios. Our results indicate that the catalytic activity strongly depends on gold:carbon support w/w ratios and on the structure and textural properties and dispersibility of the carbon supports used. Thus, the best gold-carbon catalyst performance in terms of conversion values and low carbon support content has been achieved when using graphene oxide as well as supports (carbon black, carbon nanotubes, and nanodiamond) that combine high BET surface areas, well-developed mesoporosity, and good dispersibility in water during the GNP decoration process.