Process for the manufacture of lactams
AssigneeDavy Powergas GmbH
InventorHerbert Furkert
Life of this patent
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Abstract
In a process for manufacturing a lactam which includes rearranging a cycloalkanone-oxime with sulfuric acid to form the lactam, neutralizing the rearrangement mixture with ammonia to form ammonium sulfate, and separating the lactam and the ammonium sulfate, the improvement which comprises: A. heating at least a portion of the ammonium sulfate to a temperature of 240.degree. - 460.degree. C to form ammonia and ammonium bisulfate; B. separating the ammonia from the ammonium bisulfate; C. recycling the ammonia to neutralize the rearrangement mixture; D. burning the ammonium bisulfate at a temperature of 850.degree. - 1250.degree. C to form an SO.sub.2 -containing gas; E. oxidizing the SO.sub.2 -containing gas to form sulfuric acid; and F. recycling the sulfuric acid to the rearrangement stage.
Claims18
In a process for manufacturing a lactam which includes rearranging a cycloalkanone-oxime with sulfuric acid or oleum to form said lactam, neutralizing the rearrangement mixture with ammonia to form ammonium sulfate, and separating said lactam and said ammonium sulfate, the improvement which comprises:
- a. heating at least a portion of said ammonium sulfate to a temperature of 240.degree.-460.degree. C in the presence of a molar excess of ammonium bisulfate to form a reaction mixture consisting essentially of gaseous ammonia and an ammonium bisulfate melt;
- b. separating said gaseous ammonia from said ammonium bisulfate melt;
- c. recycling said gaseous ammonia to neutralize said rearrangement mixture;
- d. burning said ammonium busulfate melt at a temperature of 850.degree.-1250.degree. C to form an SO.sub.2 -containing gas;
- e. oxidizing said SO.sub.2 -containing gas to form sulfuric acid or oleum;
- and
- f. recycling 60-100% of said sulfuric acid or oleum to the rearrangement stage.
Dependencies are inferred from the claim text.