Promotion effects of FeCu co-doping on Co3O4-based catalysts for linear α-olefins to alcohols

For the preparation of alcohols from linear α-olefins, Cu or/and Fe doped Co3O4 catalysts were synthesized using two processes and their structural and catalytic properties were studied. Using microwave-assisted and hydrothermal (HT) crystallization processes, doped Co3O4 with the rod-like morphology and the lamellar morphology were obtained, respectively, and the two morphology both showed the dominantly exposed Co3O4 (111) and (220) planes which were related to the successive hydroformylation and hydrogenation steps of olefins. With microwave-assisted process, Cu doped Co3O4 dramatically improved the hydroformylation reactivity of 1-octene. FeCu or NiCu co-doped Co3O4 raised nonanol selectivity and the promotion of FeCu co-doping was better. At 150 °C and 7 MPa for 4 h reaction, 2Fe2Cu-Co3O4(nFe:nCu:nCo = 2:2:100) exhibited 1-octene conversion of 99.82% and nonanol selectivity of 50.80%. With HT crystallization process, 2Fe2Cu-Co3O4-HT displayed 1-octene conversion of 99.69% and nonanol selectivity of 67.87% under 150 °C, 7 MPa for 5 h reaction. The effects of reaction temperature, pressure, time and catalyst dosage on the activity were discussed. At the set reaction conditions, 2Fe2Cu-Co3O4-HT exhibited high activity for C6 ∼ C12 olefins converting to C7 ∼ C13 alcohols. The roles of Cu or/and Fe doping and the effects of the exposed crystal planes of Co3O4 were revealed by characterizations.