The synthesis of diamidine dichlorinehydrate of terephthalic acid was made in two stages: 1) alcholysis of terephthalonitrile with ethyl alcohol in the presence of hydrogen chloride with obtaining dichlorinehydrate of diiminoether of terephthalic acid; 2) amination of diiminoether dichlorinehydrate with ammonium in the presence of solvent with obtaining of dichlorinehydrate diamidine of terephtalic acid. Kinetic regularities of both stage reactions have been researched.