METHOD FOR PREPARING HYDROXYLAMINE SULFATE Russian patent published in 2005 - IPC

FIELD: chemical industry and technology.

SUBSTANCE: invention relates to a method for preparing hydroxylamine sulfate (HAS) used in manufacturing caprolactam. The basic process involves catalytic oxidation of ammonia in mixture with steam and oxygen. Prepared nitrous gas is mixed with hydrogen, and its composition is stabilized on silver-manganese catalyst, concentrated by condensation of water vapors, purified from nitrogen (IV) oxide and fed to the stage of HAS synthesis. Condensation of water vapors in the composition is carried out in the carrying out heating chamber of vacuum evaporator wherein production solution with the mass part of HAS 24% is fed, and HAS solution heated to 80-90°C is fed to evaporating section of vacuum device for evaporation up to 40%. Nitric acid condensate with the mass part of nitric acid part above 1% obtained in cooling nitrous gas and condensation of water vapors are subjected for liquid-phase hydrogenation in the presence of platinum catalyst and formed nitrogen monoxide in mixture with hydrogen is fed to synthesis of HAS and the hydrogenation product with the mass part of nitric acid 0.45% is fed to diluting the concentrated sulfuric acid. As result, heat formed in condensation of nitrous gas is used for concentrating the production solution with the mass part of HAS from 24% to 40%. Method provides economy of vapor in the following stages of caprolactam manufacturing in the amount up to 1.0 t/t of caprolactam.

EFFECT: improved preparing method.

2 cl, 2 dwg