Polyvinylpyrrolidone is made from N-vinyl pyrrolidone (NVP) .
Polyvinylpyrrolidone (PVP) is prepared by polymerizing N-vinyl pyrrolidone (NVP) . Different methods can be used for this process, including solution polymerization, ontology polymerization and so on. In industry, is generally used to synthesize PVP by solution polymerization. includes solution polymerization of NVP monomer in organic solvent, followed by steam stripping and other follow-up treatment. In addition, PVP can also be prepared by free radical solution polymerization, irradiation and other methods, these methods can obtain the polymer with uniform composition and structure.
The molecular formula of PVP is (C6H9NO)n, and its physical and chemical properties are affected by the value of K. The higher the value of K, the higher the viscosity of and the stronger the adhesion of . The molecular weight of PVP can reach 1300000, and has specific water content, nitrogen content, sulfate ash and other indexes, shows its specific chemical and physical properties.
There is also an insoluble polyethylene polypyrrolidone, which is produced by the polymerization of n-vinyl-2-pyrrolidone, by cross-linking in the presence of N,N ‘-divinylimidazole with an alkaline catalyst. The insoluble polyvinylpyrrolidone is insoluble in water and common solvents, , but it has been widely used in medicine and other fields
At present, the mainstream production method of N-vinylpyrrolidone in China is acetylene method, which refers to the affinity addition reaction of acetylene and 2-pyrrolidone under specific temperature and pressure conditions by adding strong alkali catalyst such as potassium pyrrolidone to produce NVP. This method has the advantages of mature process, easy access to raw materials and suitable for large-scale production.
Polyethylpyrrolidone is a kind of polymer material with high conductivity and stability, which is widely used in the fields of electronics and optoelectronics.
The synthesis route mainly has the following methods:
1. Raw material synthesis: Through the polymerization of pyrrolidone and vinyl compounds, polyethylene pyrrolidone is obtained. The advantages of this method are that the raw material is easy to obtain, the reaction conditions are mild, but the molecular weight of the product is low.
2. Solution polymerization method: After mixing pyrrolidone, vinyl compound and solvent, polymerization reaction is carried out under the condition of adding catalyst to obtain polyethylpyrrolidone. This method can control the molecular weight and distribution of the product, but it requires the use of organic solvents, and the catalyst is vulnerable to contamination and failure.
3. Solid polymerization method: the pyrrolidone and vinyl compound are fixed on the carrier, and the polymerization reaction is carried out under the condition of adding the catalyst to obtain polyethylpyrrolidone. This method does not need to use organic solvent, and the catalyst is easy to recover and reuse, but it is difficult to select solid phase support and optimize reaction conditions.
