Homogeneous Oxidation Reactions of Propanediols at Low Temperatures

EVA DÍAZ; MARÍA EUGENIA SAD; ENRIQUE IGLESIA

CHEMSUSCHEM

WILEY-V C H VERLAG GMBH

Año: 2010 vol. 3 p. 1063 - 1070

1864-5631

O2 reacts with propanediols via homogeneous pathways at400–500 K. 1,2-Propanediol forms CH3CHO, HCHO, and CO2 viaoxidative CC cleavage and acetone via dehydration routes,while symmetrical 1,3-propanediol undergoes dehydration andoxidative dehydrogenation to form, almost exclusively, acrolein(ca. 90% selectivity). The products formed and their kinetic dependenceon reactant concentrations are consistent with radical-mediated pathways initiated by O2 insertion into CHbonds in a b position relative to oxygen atoms in diol reactants.Propagation involves b-scission reactions that form hydroxyland hydroxyalkyl radicals. Acrolein/O2/H2O mixturesfrom the homogeneous oxidation of 1,3-propanediol formacrylic acid (with 90% yield) in tandem reactors containingmolybdenum-vanadium oxide catalysts. These data reveal theunique reactivity of diols, compared with triols and alkanols, inhomogeneous oxidations, while also providing useful insightinto the molecular basis for reactivity in biomass-derived oxygenates