Bubble‐ and critical‐points in the ammonia–carbon dioxide plane and ammonia–urea system are presented as well as bubble‐points in the carbon dioxide–urea system. In order to confirm the form of a previously presented phase model a large number of bubble‐ and dew‐points were measured at various ammonia–carbon dioxide–water–urea compositions (including those most important to the urea industry) in the range of 140 ⩽ T ⩽ 200°C and 15 < P < 400 atm. All of the measurements were carried out under conditions of complete chemical equilibrium. The results are in agreement with the ternary phase model presented in a previous article.

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