| 摘要 |
<p>In the anionic polymerization of 2-pyrrolidone involving the use of an alkali metal pyrrolidonate as the catalyst and CO2, SO2 or MoO3 as the activator certain quaternary ammonium salts of mineral acids are added to markedly accelerate the rate of polymerization. The quaternary ammonium compound may be recovered and recycled by washing the polymer formed with a suitable solvent. The structural formula of the quaternary ammonium accelerators is (FORMULA) 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 also act as color suppressors when sulfur dioxide is used as the 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. </p> |
