Dehydrogenation with SiO₂-Supported Iridium Catalysts

Significance

The dehydrogenation of isopentane with silica-supported iridium complexes was carried out at high temperature (400-450 °C) to give isopentene and hydrogen. When four equivalents of triphenylphosphine (based on Ir) were added to the silica gel supported H₂IrCl₆ catalyst, the conversion into isopentene increased from 2% (without triphenyl­phosphine) to 33%. The catalytic activity for the dehydrogenation was strongly affected by the concentration of phosphine ligands (without: 2.3% conv.; 1 equiv: 9.8% conv.; 4 equiv: 21.9% conv.; 8 equiv: 26.1% conv.).