Hydrolysis of Diammonium Imidobis(sulfate) and Ammonium Amidosulfate Mixture at Elevated Temperature

Abstract

Hydrolyses of coexisting NH(SO₃NH₄)₂ and NH₄SO₃NH₂ has been studied in the presence of guanidinium sulfate and (NH₄)₂SO₄ from 100 to 160°C, at which temperature range no decomposition of guanidinium ion was observed. It was confirmed that hydrolysis of the NH₂S0₃^- in an aqueous solution was much slower than that of NH(S0₃^-)^2- in the same solution and that the former hydrolysis proceeds through the reaction between NH₂S0₃^- and H₃0⁺ formed by the preceding hydrolysis of NH(S0₃^-)₂. On the other hand, hydrolysis of the NH₂S0₃^- in the presence of a small amount of water was found to be accelerated by the addition of NH(S0₃NH₄)₂ and to occur in preference to that of the coexisting NH(S0₃)₂ above 120°C. The reaction path in this case was presumed as follows. An actual reaction mixture(guanidinium ion: 14.4, NH₄⁺: 14.5, SO₄^2-: 30.6, NH(S0₃^-)₂: 23.5, NH₂S0₃^-: 13.9%) obtained in a guanidine synthesis was hydrolyzed in the presence of a small amount of water on the basis of the above results. It was readily converted into a mixture of guanidinium sulfate, (NH₄)₂SO₄ and H₂SO₄.