Abstract: A method of producing xylylenediamine by a two-stage hydrogenation of a starting phthalonitrile in a solvent. The main steps of the method are a hydrogenation step 1 and a hydrogenation step 2. In the hydrogenation step 1, a solution of the starting phthalonitrile in the solvent containing liquid ammonia is fed to an inlet of a first reaction zone and the hydrogenation is carried out in the first reaction zone in the presence of a heterogeneous catalyst, to hydrogenate nitrile groups in the starting phthalonitrile to aminomethyl groups. A part of the hydrogenation product solution from the first reaction zone is circulated to the inlet of the first reaction zone and the rest is introduced into the hydrogenation step 2 where further undergoes the hydrogenation.

Abstract: A method of producing xylylenediamine of the present invention includes the steps of: subjecting a liquid mixture of phthalonitriles with liquid ammonia or a mixture of liquid ammonia and an organic solvent to a first catalytic hydrogenation treatment, thereby hydrogenating the phthalonitriles to obtain a reaction product (A), wherein a content of the liquid ammonia or the mixture of liquid ammonia and an organic solvent is 80 wt % or more; removing the liquid ammonia in the reaction product (A) to obtain a reaction product (B); subjecting the reaction product (B) to a second catalytic hydrogenation treatment, thereby hydrogenating cyanobenzylamine to obtain a reaction product (C); and distilling the reaction product (C) to purify xylylenediamine.

Abstract: A method of producing xylylenediamine by a two-stage hydrogenation of a starting phthalonitrile in a solvent. The main steps of the method are a hydrogenation step 1 and a hydrogenation step 2. In the hydrogenation step 1, a solution of the starting phthalonitrile in the solvent containing liquid ammonia is fed to an inlet of a first reaction zone and the hydrogenation is carried out in the first reaction zone in the presence of a heterogeneous catalyst, to hydrogenate nitrile groups in the starting phthalonitrile to aminomethyl groups. A part of the hydrogenation product solution from the first reaction zone is circulated to the inlet of the first reaction zone and the rest is introduced into the hydrogenation step 2 where further undergoes the hydrogenation.

Abstract: A method of producing xylylenediamine of the present invention includes the steps of: subjecting a liquid mixture of phthalonitriles with liquid ammonia or a mixture of liquid ammonia and an organic solvent to a first catalytic hydrogenation treatment, thereby hydrogenating the phthalonitriles to obtain a reaction product (A), wherein a content of the liquid ammonia or the mixture of liquid ammonia and an organic solvent is 80 wt % or more; removing the liquid ammonia in the reaction product (A) to obtain a reaction product (B); subjecting the reaction product (B) to a second catalytic hydrogenation treatment, thereby hydrogenating cyanobenzylamine to obtain a reaction product (C); and distilling the reaction product (C) to purify xylylenediamine.

Abstract: In a method of producing pyromellitic acid by liquid-phase oxidizing 2,4,5-trimethylbenzaldehyde in a water solvent with molecular oxygen, a recrystallization mother liquor separated in a recrystallization step is recycled to the oxidation step after a part of the water solvent is removed. With this method, the loss of pyromellitic acid and the oxidation catalyst can be minimized and the burden of discharging the waste water is reduced without lowering the efficiency of the liquid-phase oxidation reaction.

Abstract: In a method of producing pyromellitic acid by liquid-phase oxidizing 2,4,5-trimethylbenzaldehyde in a water solvent with molecular oxygen, a recrystallization mother liquor separated in a recrystallization step is recycled to the oxidation step after a part of the water solvent is removed. With this method, the loss of pyromellitic acid and the oxidation catalyst can be minimized and the burden of discharging the waste water is reduced without lowering the efficiency of the liquid-phase oxidation reaction.