甲基铝氧烷的合成

Synthesis of methylaluminoxane

用含水硅胶作为三甲基铝的水解剂制备了甲基铝氧烷(MAO),研究了影响MAO收率及聚合活性的因素,得到了合成MAO的最佳反应条件。结果表明,水/TMA(摩尔比)、三甲基铝的滴加时间、低温反应时间对MAO的收率及其聚合活性有直接影响,硅胶中水的质量分数对MAO反应收率有较明显的影响,而对MAO的聚合活性影响不大。合成MAO反应的最佳工艺条件是:水/三甲基铝(摩尔比)1.4,三甲基铝滴加时间1h,低温反应时间2h。在最佳工艺条件下,MAO的反应收率可达到49%。

The methylaluminoxane (MAO) was synthesized by hydrolysis of trimethly aluminum (TMA) with silica gel containing water. The factors influenced the yield and the polymerizing activity of MAO were discussed. The optimum conditions were obtained. The results showed that the yield and the polymerizing activity were directly affected by H2O/TMA (molar ratio), time of TMA addition and reaction time at lower temperature, and mass fraction of water in silica gel had obvious effects on yield, but had no effect on the polymerizing activity. The optimum conditions of synthesis MAO were H2O/TMA (molar ratio) 1.4, time of TMA addition 1 h and reaction time 2 h at lower temperature. The yield of 49% of this reaction could be attained under the above conditions.