Ureas and isocyanates

Both reagents have proved to be useful substitutes for phosgene in all its main applications. Indeed, they are sold commercially as the efficient equivalents of 2 and 3 phosgene molecules respectively in processes yielding chloro-formates, carbonates, carbamates, ureas and isocyanates, as well as in chlorinations, carboxylations and dehydrations (For a recent review of Triphosgene use in organic synthesis, see Ref. 33). 

Also similarly to the allophanate formation, the reaction between urea and isocyanates is an equilibrium reaction and needs higher temperatures too ( > 110 °C). 

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