HYDROXYLAMINE SULFATE PRODUCTION PROCESS Russian patent published in 2006 - IPC C01B21/14 

FIELD: industrial organic synthesis.

SUBSTANCE: hydroxylamine sulfate (caprolactam precursor) is prepared by mixing at excessive pressure in reaction space synthesis gas consisting of nitrogen monoxide and hydrogen, sulfuric acid/water mixture, and, as catalyst, platinum deposited on electrode graphite. Process is carried out in presence of 2-30% aqueous solution of complexing agent composed of hydroxyethylidene-1,1-diphosphonic acid CH₃-C(OH)=[P(O)(OH)₂]₂ (I) and cyclic P-complex (II) having general formula: , wherein A represents =P(O)CH₃OH, and I/II molar ratio 1:1 and weight ratio of aqueous solution of complexing agent and iron contained in reaction system 100-500 ppm per 1 ppm Fe.

EFFECT: more than thrice reduced NO content in emission gases, increased yield of hydroxylamine sulfate (principal reaction product), and prolonged service cycle of catalyst.

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