Through further research, the hydrolysis mechanism of NVP in the presence of acrylic acid or KSO was obtained. The vinyl charge in the NVP molecule is unbalanced, that is, the charge density on the two carbon atoms connected by the double bond is different. This charge imbalance provides the possibility for the hydrolysis of NVP. When in acid or in the presence of alkali metal ions, isomerization occurs in the NVP molecule to form a series of transition states, and finally pyrrolidone and acetaldehyde are generated. This is one step of NVP hydrolysis. The second step of NVP hydrolysis is that the pyrrolidone generated in the first step reacts with the NVP molecule, and then further decomposes into pyrrolidone and acetaldehyde with the participation of water. From the perspective of the NVP hydrolysis mechanism, whether NVP can be hydrolyzed depends mainly on whether a series of transition states can be formed in the first step, or whether the isomerization reaction in the NVP molecule can occur is the key to whether NVP can be hydrolyzed.
The presence of H* or alkali metal cations in the solution enables the intramolecular isomerization of NVP to be realized, so the hydrolysis of NVP can proceed. The hydrolysis rate of NVP mainly depends on the second step. When K' exists, it will react with the pyrrolidone generated in the first step to generate pyrrolidone potassium salt, and then react with NVP for addition reaction. Obviously, pyrrolidone potassium salt is easier to react with NVP for addition reaction, resulting in that the hydrolysis rate of NVP should also be greater when K, SO exists.
