[Anthasci]

I have a question regarding this specific reaction, I apologize for the puny ms paint picture, but I don't have any software on this computer here. Well, the question is basically written within the picture. Why isn't CO₂ eliminated here, contrary to this reaction, for example:

Ph-N=C=O + H₂O = Ph-NH₂ + CO₂

I can't wrap my head around it and having -Ph in both cases on the C-atom isn't helpful either. Could anyone shed some light on this for me, please?

Thanks

[Dan]

If you draw the mechanism for decarboxylation of the carbamic acid and compare it to a mechanism for your proposed decarboxylation, you should see why the former is much easier.

[Anthasci]

I may have some ideas. In the case of carbamic acid, the Nitrogen atom has a lone pair, which can attract the carboxylic proton? It is also more electronegative than the C-atom, in regard to the 2,2-diphenylethanoic acid