Removal of unstaturated contaminants from an industrial C4-stream using Cu/SiO2 catalysts: Subsequent testing of the purified stream with an alkyne sensitive catalyst system Original Research Article

A recently developed, highly selective, CuSiO2 catalyst for the hydrogenation of unsaturated hydrocarbon contaminants in C2 and C3 alkene streams has been employed to remove alkynes from an industrial C4 cracker stream. At a temperature of 320°C and with approximately equal concentrations of H2 and C4 feed effectively all the contaminating alkynes and all the butadienes were hydrogenated selectively to butenes. No further hydrogenation of butenes to butanes was detected. The purified C4-stream was successfully employed in a butene dimerization reaction catalyzed by a homogeneous, Ziegler-type nickel catalyst system [Ni (dithioacetylacetonato) (PnBu3) Cl + diethylaluminiumchloride]. Prior to selective hydrogenation, alkynes present in the C4 stream had poisoned the nickel catalyst. After removing the contaminants dimerization proceeded with an activity (1480 turnovers/h) and product distribution in line with that observed using pure 1-butene feeds.