| 摘要 |
Quarternary ammonium salts are used as adjuncts to the primary catalyst of an alkali metal pyrrolidonate in the polymerization of 2-pyrrolidone using SO2, CO2 or MoO3 as initiator. The catalysts may be recovered and recycled by washing the resultant polymer with a solvent. The structural formula for the quarternary ammonium salt is <CHEM> wherein R1, R2, R3 and R4 are alkyl, aralkyl, or aryl radicals, n is 1 or 2 depending on the valence of X, and X is a sulfate, hydrogen sulfate or halide. Such quaternary ammonium salts reduce conversion time for polymerization and also act as color suppressors when sulfur dioxide is used as an activator at higher temperatures. Also disclosed is the use of a cesium or rubidium pyrrolidonate as a color suppressor in the SO2 activated 2-pyrrolidone polymerization. |
