Water → Urea oxalate

Participants

Reaction Steps

Referring now more specifically to the FIGURE, 3 represents any vessel suitable for containing the reaction mixture. Urea phosphate 2, oxalic acid 1, and water in the form of dilute phosphoric acid 4 are fed to reactor 3 to form a slurry of urea oxalate in purified phosphoric acid. The slurry is fed via line 5 to cooler 6 and then via line 7 to filtering and washing apparatus 8. The filtrate is purified phosphoric acid and it is withdrawn via line 9 as product. The urea oxalate filter cake is washed with water via line 10 to recover the adhering phosphoric acid. The filtrate from the washing step is dilute phosphoric acid which is recycled to reactor 3 via line 4. The urea oxalate filter cake from apparatus 8 is fed via line 11 to reactor 12 where it is heated to thermally decompose it into oxamide and urea with the expulsion of water and carbon dioxide. Or, if desired, part or all of the urea oxalate filter cake from apparatus 8 is fed via line 13 to reactor 15 where it is neutralized with ammonia fed via line 14 to produce a mixture of urea and ammonium oxalate.

Provenance & Evidence