ABSTRACT:The process of partial hydrolysis reaction of TMA with water and the interaction of zirconocene dichloride (Cp 2 ZrCl 2 ) with TMA, MAO, and the in situ partially hydrolyzed products of TMA were studied by in situ Al-NMR spectroscopy. The 1 H-NMR spectra of MAO samples and the in situ hydrolyzed products of TMA with water under different conditions are different. A new peak at ␦ ϭ Ϫ0.58 ppm in 1 H-NMR spectra is observed, and is supposed to be due to the methyl resonance of MAO with low molecular weight. Alkylation reaction is observed between Cp 2 ZrCl 2 and TMA, MAO, and the in situ hydrolyzed products of TMA, and TMA is supposed to be the actual alkylating agent.27 Al-NMR studies show that MAO is tetra-coordinated.