DIMERIZATION OF N-BUTENES ON AMORPHOUS NIO-AL2O3/SIO2 CATALYSTS

The conversion of different n-butenes on amorphous NiO-Al2O3/SiO2 catalysts has been studied in the liquid phase at 3.5 MPa and 370 K. The product distribution is consistent with a coordinative as well as carbenium ion dimerization mechanism, while the preferable conversion of but-1-ene points to the coordinative dimerization mechanism. Isomerization reactions of oligomers on acid sites take place, while the isomerization of the n-butenes is of minor importance. Catalyst deactivation by coke formation is caused by condensation products of Diels-Alder type reactions as well as multi-unsaturated oligomers. Transformation of cis-but-2-ene is accompanied by pronounced formation of coke precursors.