METHOD OF PREPARING HYDROXYL-AMMONIUM SALTS Russian patent published in 1999 - IPC

FIELD: chemical industry. SUBSTANCE: hydroxyl-ammonium salts are prepared by catalytic reduction of nitrogen oxide in the presence of acid substance on hydrogenation catalyst, recovery of desired product by filtration of the resulting reaction mixture and recirculation of residue into process. Filtration residue of the resulting reaction mixture is subjected to sedimentation and residue thus formed is recycled into process. Sedimentation is carried out for 0.5-10 min during heating procedure. EFFECT: increased yield per unit of volume/time. 4 cl, 2 ex