METHOD OF RECOVERING UNREACTED AMMONIA FROM STREAM FLOWING OUT OF REACTOR Russian patent published in 2004 - IPC

FIELD: industrial organic synthesis.

SUBSTANCE: invention relates to improved method for reduction and recovery of unreacted ammonia from flowing out stream containing acrylonitrile or methacrylonitrile and coming out from reaction zone, where oxygen, ammonia, and hydrocarbon selected from propane and isobutene are brought into contact in reactor in presence of fluidized ammoxidation catalyst bed at elevated temperature to produce corresponding unsaturated nitrile by cooling flowing out stream containing corresponding nitrile and unreacted ammonia with first aqueous ammonium phosphate solution, wherein ratio of ammonium ions to phosphate ions (PO3-4

) varies between 0.7 and about 1.3, to absorb essentially all unreacted ammonia present in flowing out stream to form second aqueous ammonium phosphate solution more rich in ammonium ions than the first solution. Second solution is then heated to temperature high enough to reduce amount of ammonium ions in the second solution to essentially the same level as in the first solution and to form ammonia-containing vaporous stream, which is returned into reactor.

EFFECT: avoided formation of ammonium salt-containing waste, achieved complete capture of acrolein, and reduced content of organic carbon and polymers in organic dregs.

18 cl, 2 dwg