PRODUCTION OF TETRACHLORO-ORTHO-PHTHALONITRILE

PROBLEM TO BE SOLVED: To efficiently obtain tetrachloro-ortho-phthalonitrile by removing the self-condensation products of ortho-phthalonitrile as a raw material by a specific means, wherein the self-condensation products are generated, when the ortho-phthalonitrile is vaporized and subsequently subjected to a chlorination reaction. SOLUTION: This method for producing tetrachloro-ortho-phthalonitrile comprises reacting a gas containing ortho-phthalonitrile with chlorine gas in the presence of a catalyst in a gaseous phase. Therein, ortho-phthalonitrile self-condensation products generated before, after or during the vaporization of the ortho-phthalonitrile are removed and subsequently subjected to the chlorination reaction. The self-condensation products of the ortho-phthalonitrile is the ortho-phthalonitrile linear polymer of the formula (n is 2-8), especially 2,4,6- tri(o-cyanophenyl)-1,3,5-triazine. A method for removing the self-condensation products includes a method comprising liquidizing and separating the self- condensation products preferably by the use of a condenser on the vaporization of the ortho-phthalonitrile. The total content of the self-condensation products is preferably controlled to