NEW METHOD FOR THE DETERMINATION OF THE TRIALKYLALUMINUM CONTENT IN ALUMOXANES

摘要

Alkylalumoxanes (such as methylalumoxane, MAO) can contain ''free'' trialkylaluminum (AlR(3)). The relative ratio of the latter in any sample may be determined by P-31 NMR spectroscopy upon addition of excess PPh(3). The rapid exchange of free PPh(3) and Me(3)-Al . PPh(3) results in the P-31 NMR signal being a weighted average from which an accurate determination of AlR(3) can be made, based on an external standard. This analysis method has been. demonstrated for the determination of AlMe(3), AIEt(3), and Al(i)Bu(3) in methydalumoxane (MAO), ethylalumoxane (EAO), and isobutylalumoxane (IBAO) and bis(diisobutylaluminum oxide) (DBAO), respectively. [References: 13]