Catalytic vapor phase ammoxidation reaction of o-xylene was investigated. The activity of the vanadium pentoxide (V2O5)-pumice catalyst to the formation of o-phthalonitrile was low, and gave mainly phthalimide. Therefore the effect of addition of various additives on V2O5 was investigated. It was found that the addition of P2O5 to V2O5 gave remarkable improvement in the activity of formation of o-ph-thalonitrile. Namely, V2O5-P2O5-fire-resisted stone catalyst under the reacting condition (molar ratio of P2O5/V2O5=0.25, reaction temperature 480°c, gas space velocity 790 cc/cc. hr (NTP) NH3/o-xylene ca. 8 moles) yielded ca. 50 mole% o-phthal- onitrile and ca. 12 mole % of phthalimide. An increase in the activity for formation of o-phthalonitrile by the addition of P2O5 was probably brought by the lowering of activity for the oxidative decomposition of ammonia by the catalyst and of the excessive oxidation of o-xylene and by the increasing activity for the formation of o-phthalonitrile by the reaction of oxidation product of o-xylene with ammonia. Also, V2O5-P2O5-fire-resisted stone catalyst showed the high activity for the oxidative decomposition of ammonia at the initial period of reaction, which was gradually decreased to a fixed value with the time of reaction, while the rate of formation of o-phthalonitrile was low at the beginning, then reached to a fixed higher value after certain period.
The optimum condition for vapor phase catalytic chlorination reaction of ο-phthalonitrile in the presence of activated carbon catalyst was investigated. When the reaction temperature was 250-300°c, the velocity of feeding of ο-phthalo-nitrile 0.2-0.5 × 10-3 mol/g.hr and Cl2/PN, (ο-phthalonitrile) above 6 moles, the yield of tetrachlorophthalonitrile above 90 mole % and that of hexachlorobenzene below 3 mole % were obtained. The change of activity of activated carbon catalyst during the reaction time was investigated up to 110 hrs, but no decreasing activity was observed. The relation between the condition for preparation of activated carbon and its chlorination activity was investigated. For obtaining activated carbon catalyst of high chlorination activity, it was necessary to keep steaming temperature above 750°c with enough time. With the progress of activation by steaming, the time required for preliminary chlorinating treatment can be shortened and the rate of increase in weight of catalyst after the reaction is increased. The mechanism of chlorination of o-phthalonitrile was considered to proceed through the route of ο-phthalonitrile → 4-monochlorophthalonitrile → 4, 5-dichlorophthalonitrile →tetrachlorophthalonitrile.