C-6-alkane reactions over gamma-alumina supported palladium catalysts

A series of Pd/Al2O3 catalysts of different Pd loading were tested in C-6-a lkane reactions. Different catalyst pretreatment was used to change both th e acidity of alumina and the state of palladium. A parallel study with the use of n-hexane and 2,2-dimethylbutane showed several similarities in the c atalytic behaviour of the Pd/Al2O3 catalysts. Highly reduced catalysts show ed completely different performance than samples reduced at lower temperatu res. High temperature reduction leads to a big enhancement of catalytic act ivity and also vastly increases the isomerization selectivity. Considerable changes were also noticed in the activation energy. Oxidation and subseque nt mild reduction of highly reduced samples brings about, however, differen t results for isomerization selectivity: a partial recovery in the case of n-hexane and only a very small change for the 2,2-dimethylbutane reaction. The results confirm the major contribution of acidic sites present in activ ated alumina to the overall catalytic behaviour of Pd/Al2O2 samples.