This is a fun reaction that may be of use in the production of anhydrous ammonia.
Everyone knows dimethyl carbonate, right? Useful alkylating agent, etc? Well, one method of making it works like this:
H2N-CO-NH2 + HOCH2CH2OH --> CO(OCH2)2 + 2 NH3
CO(OCH2)2 + 2 ROH --> HOCH2CH2OH + CO(OR)2
Well, this suggests that by heating anhydrous ethylene glycol with urea, one will obtain anhydrous ammonia. Just use the reaction above. I will post some papers on this process shortly. The advantage of this method is that there's no water produced, as in the standard ammonium salt neutralization, and all the ingredients are cheap.
The cyclic carbonate produced may also have some use. For example, if pyrolyzed, it may yield ethylene oxide.