A novel glycerol valorization route: chemoselective dehydrogenation catalyzed by iridium derivatives

Organoiridium derivatives of the type Ir(diene)(N-N)X (diene = 1,5-hexadiene,1,5-cyclooctadiene; N-N = 2,2'-bipyridine, 1,10-phenanthroline and substituted derivatives; X = Cl, I) catalyze the hydrogen transfer reaction from glycerol to acetophenone, yielding dihydroxyacetone and phenylethanol. The catalytic reactions are performed at temperatures of 100 °C or higher, in the presence of a basic cocatalyst. The effect of experimental conditions on overall conversion and catalyst lifetime is discussed, as well as on the degradation of dihydroxyacetone, which can lead to an apparent decrease of selectivity of the catalytic reaction.