The hydroisomerization activity of nickel-substituted mica montmorillonite clay

Three-layer sheet aluminosilicates, when exchanged into the acidic form, are far less active as hydroisomerization catalysts than zeolites having a comparable surface proton density. However, introducing Ni2+ or Co2+ into the octahedral positions of the Al3+ layer in synthetic beidellite results in hydroisomerization catalysts of an activity similar to that of a zeolite. From pyridine poisoning experiments and FT/IR measurements it can be concluded that this increased activity stems from the increased acidity of the resulting NiSMM (Ni-synthetic mica montmorillonite) clay, due to reduction of Ni. By intercalating the clay with aluminium oligomers "pillared" clays of enhanced surface area have been synthesized. The increase in catalytic activity with enhanced basal surface area indicates that the acidic sites are located in the basal plane of the synthetic clay particles