Ethylene polymerization with zirconocene catalyston zeolite A support derived from fly ash

Abstract

Zeolite A (LTA) synthesis from fly ash has many applications, in which metallocene catalytic support is uncommon. This research study has three parts. Firstly, investigation of the effects of immobilized MAO cocatalyst and zirconocene catalyst techniques on silica support. Immobilized MAO, followed by metallocene catalyst method had the highest catalytic activity, which was used in the next parts. The second part examined the optimal temperature and [Al]MAO/[Zr]cat ratio with ethylene polymerization in a semi-batch autoclave reactor utilizing LTA-supported metallocene catalysts. The optimal conditions were found at 80°C and [Al]MAO/[Zr]cat ratios equal to 2000 that were used in the next section. LTA-MAO/Zr showed lower catalytic activity than silica-supported catalysts. This is because acidity disrupted polymer chain formation and reduced crystallinity. Finally, a comparison of three zeolite supports for ethylene and ethylene/1-hexene polymerization was conducted. LTA-MAO/Zr had the best catalytic activities among ZSM5 and BEA support because of a higher Al/Zr ratio and Lewis acidity, which corresponded to the catalyst activity. However, we cannot generalize that high zeolite support acidity leads to high catalyst activity because it depends on multiple factors. Therefore, LTA was an optimally supported metallocene catalyst system.