  We propose the theoretical description for the temperature and concentration
phase transformations in composite lithium grease doped with the mesogenic
additives of the copper(II) carboxylates family, copper(II) valerate and
isovalerate, in the concentration range 1, 5, 10, 20 wt. percents. The changes
in character of specific electric conductivity of these composites manifested
in experiments on dielectric spectroscopy in the measuring electric field of
the frequencies 100 Hz - 1 MHz and polarization microscopy, are reliable caused
by reversible phase transitions from the discotic phase to isotropic one or at
heating from room temperature to 391 K. We study correlations between defect
structure and electrical properties of these composites using the model of the
BKT transition. This transformation from the discotic to isotropic phase is
associated with the evolution of topological defects dislocations induced by
the mesogenic additives. The screw, transverse edge and longitudinal
dislocations are realized in this case. We apply the numerical Monte Carlo
technique to define their critical properties in the BKT transition.
