Catalytic hydrocarboxylation of acetylene to acrylic acid using Ni2O3 and cupric bromide as combined catalysts

A non-petroleum route to produce acrylic acid was investigated through hydrocarboxylation of acetylene with CO and water in the presence of Ni 2 O 3 and cupric bromide as combined catalysts. The activity of Ni 2 O 3 was compared with various homogeneous catalysts; the effect of initial total pressure, reaction temperature, molar ratio of CO/C 2 H 2 , the volume ratio of solvent/water, the catalyst amount and the role of promoters have been studied in detail. It was found that the acrylic acid space-time-yield as high as 764.6   mol AA/(mol Ni   h) was obtained under the optimal experimental conditions. The Ni 2 O 3 catalyst could be reused at least five times without obvious loss of activity. The characterization of recovered catalysts by XRD, XPS, SEM and TG–DTG revealed that the state of nickel remains unchanged during the reaction, and there are three types of soft coke deposited on the surface of the catalyst. The catalysts can be regenerated through calcination within 400   °C according to TG curve.