Characterization of Methylaluminoxanes and Determination of Trimethylaluminum Using Proton NMR

Abstract

New methods for characterization of methylaluminoxanes (MAO) and determination of trimethylaluminum (TMA) using proton NMR are reported. Addition of excess perdeuteriotetrahydrofuran to sharpen and shift the TMA peak followed by curve fitting to remove residual overlap between the TMA and MAO peaks allows accurate, precise, and rapid quantitation of TMA and MAO in solution. The analysis also provides determination of all the solution components of MAO preparations and the number of methyl groups per aluminum in MAO when combined with an independent determination of the aluminum content.