烷基改性甲基铝氧烷的合成及在乙烯聚合中的应用

Synthesis of methylaluminoxane modified by alkyl and its application in ethylene polymerization

为降低茂金属催化剂用助催化剂甲基铝氧烷(MAO)的合成成本,研究了乙基改性MAO(MMAO-Et)和异丁基改性MAO(MMAO-i-Bu)的合成及其在乙烯聚合中的应用。结果表明:当n(三乙基铝)/n(三甲基铝)为0.15时,MMAO-Et的助催化活性{m(聚乙烯)/[n(Zr).h]}为282 kg/(mol.h),与MAO的助催化活性[285 kg/(mol.h)]相当;当n(异丁基)/n(甲基)为0.35,当n(三异丁基铝)/n(三甲基铝)为0.45时,MMAO-i-Bu的助催化活性分别为368,336 kg/(mol.h);用改性MAO制备的聚乙烯物理机械性能与用MAO制备的相当。

In order to decrease the synthesis cost of methylaluminoxane（MAO） as the co- catalyst of metallocene catalyst, the synthesis of ethyl modified MAO （ MMAO - Et） and isobutyl modified MAO （ MMAO - i - Bu） were studied, and their applications in ethylene polymerization were introduced. The results showed that when the molar ratio of triethyl aluminium to trimethyl aluminium was 0.15 ,the catalytic activity{m（polyethylene）/[n（Zr） · hi]} of MMAO - Et was 282 kg/（mol · h）, which was equivalent to that of MAO [285 kg/（mol · h）]. When the molar ratio of isobutyl to methyl was 0.35 and the molar ratio of tri - isobutyl aluminium to trimethyl aluminium was 0.45 ,the co - catalytic activity of MMAO - i - Bu was 368,336 kg/（ mol · h） respectively. The physical mechanical properties of polyethylene （PE） prepared with the modified MAO were equivalent to that of PE synthesized with MAO.