PNNL

Abstract

The presence of alkali (Na+ or Li+) or alkali-earth (Ca2+ or Mg2+) cations adjusting the acid-base properties on amorphous silicaalumina influences markedly the catalytic properties of supported Ni for 1-butene dimerization. The low concentration of Brønsted acid sites on these catalysts reduces the double bond isomerization of butene and inhibits the formation of dimethylhexene as primary product. While the alkali and alkali-earth cations act as weak Lewis acid sites, only Ni2+ sites are catalytically active for dimerization of 1-butene. n-Octene and methylheptene are formed selectively as primary products; dimethylhexene is a secondary product. The open environment of the Ni2+ sites does not induce different reaction pathways compared to Ni2+ in the pores of zeolites.