The data on the viscosity of the tar when dissolving non-substituted aromatic compounds (naphthalene and anthracene) were received. The viscosity coefficients of available empirical equations when adding the naphthalene and anthracene were determined. The rheological properties of the tar on a Brookfield viscometer were investigated with imitative additives. Irregular values of energy activation of viscous flow were established with the additive of certain amount of naphthalene that also correlated with the minimum value of the constant K2 of Walter equation and constant В in the equation of Cornelissen-Waterman. The above data allow to recommend the temperature ranges and optimal amount of naphthalene for obtaining coal tar with improved rheological properties.
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