CO(NH2)2 + 2 Cl2 => CO(NHCl)2 + 2 HCl
∆Hf (Heat of formation) of urea = - 333.1 kJ/ mol
∆Hf (Heat of formation) of HCl = - 92.3 kJ/ mol
2 (- 92.3) - (- 333.1) = + 148.5 kJ/ mol , supposed ∆Hf (Heat of formation) of CO(NHCl)2
High endothermicity is why it is explosive.
Acid anions can be made to substitute hydrogen in urea.
The remaining hydrogen of chloinated urea is acidic.
If it is no longer basic it cannot form a salt with another acid.
It may however form one with a base.
Dichlorurea and HNO3 both being acids will be miscible.
NO3- will displace Cl- , decomposing and hydrolyzing the remainder.
Dichlorurea is so reactive and unstable it can only serve
as a reagent or precursor.
The Action of Chlorine upon Urea Whereby a Dichloro Urea is Produced
F.D.Chattaway , Journal Proceedings of the Royal Society of London. Series A
Vol 81, Number 549 / December 22, 1908 , Pages 381-388
http://www.sciencemadness.org/talk/files.php?pid=169616&...
Excerpted below from pages 386 and 387 :
Dichlora urea cannot be kept for any length of time without change.
When damp it hydrolyses exactly as when dissolved in water, To obtain
it pure, therefore, it must be dried very rapidly over phosphoric oxide in
a vacuum. When only freed from adhering water as far as possible by a
pump, it is slowly hydrolysed by the retained moisture even though
placed in a desiccator over strong sulphuric acid, and this often occurs
to such an extent that the mass becomes quite yellow from the nitrogen
chloride mechanically retained by the crystals. To show the amount of
hydrolysis which takes place under these conditions a quantity of the
pure substance freed from all but adhering water thus was kept over
strong sulphuric acid, and analysed from time to time, the nitrogen
chloride formed being allowed occasioually to escape, In two days the
percentage of chlorine as : NCI had fallen to 43.79 and in seven days to
13.33.Even when dried and kept over phosphoric oxide it slowly
decomposes, nitrogen chloride being evolved. A quantity of the pure dry
compound thus preserved in a vacuum over phosphoric oxide was
analysed at intervals; after 12 hours the percentage of Cl as : NCi had
fallen to 54.67, after two days to 52.97, and after nine days to 47.87
per cent.
Its behaviour with acids is complicated by the circumstance that it is so
readily hydrolysed; for example, when it is added to strong hydrochloric
acid though chlorine is rapidly given off the amount of urea reformed is
not very large. When placed in cold strong sulphuric acid it is hydrolysed
and nitrogen chloride is liberated. The latter decomposes into its elements
if the liquid be heated, its characteristic smell disappearing and being
replaced by that of chlorine
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