The basic schemes for the transformation of the pentane-hexane fraction catalytic isomerization, which are probable from the point of view of thermodynamics, have been considered. Based on the literary analysis of possible transformation schemes, the mechanism of the process and on the basis of experimental data, a mathematical model of the reactor block of the process was constructed and the kinetic parameters were determined. The foundations were laid for the subsequent solution of the tasks of the multi-purpose optimization of the catalytic isomerization process of the pentane-hexane fraction.