Abstract: A process for activating and maintaining a catalyst used in isomerizing a C8 alkyl aromatic hydrocarbon containing feedstock. The activation of the catalyst is accomplished through the oxidation and reduction of the metal component in the catalyst. The oxidation of the metal component is accomplished by circulating a stream of nitrogen containing about one percent oxygen at a temperature of about 480° C. The oxidized metal component is then reduced by circulating pure hydrogen through the reactor over a range of specific pressure and temperature conditions. On completing the activation of the catalyst a feedstock is then circulated through the catalyst to isomerize a C8 alky aromatic feedstock. The positive activity of the catalyst is maintained during the isomerization process by recycling a hydrogen-rich fraction having a high hydrogen purity.

Abstract: An improved C.sub.8 alkyl aromatic hydrocarbon isomerization process comprising the steps of (1) contacting the feedstock with an isomerization catalytic composite in the presence of hydrogen at isomerization conditions to isomerize at least a portion of the C.sub.8 alkyl aromatic hydrocarbons and to produce an effluent; (2) separating the effluent to form a hydrogen-rich gaseous fraction, a first hydrocarbon-rich fraction containing toluene and having a lower average molecular weight relative to C.sub.8 alkyl aromatic content, and a second fraction enriched in C.sub.8 alkyl aromatic content relative to the effluent; provided that at least a portion of the first hydrocarbon-rich fraction is subjected to the contacting of step (1); and (3) recovering at least one C.sub.8 alkyl aromatic product from the second fraction. Improved yields of specific desired C.sub.8 hydrocarbon isomers and more efficient and complete C.sub.8 alkyl aromatic isomerization are among the benefits obtained.