Alkylalumoxanes - Preparation, Structure and Role in Single-Site Technology

3 Alkylalumoxanes - Preparation, Structure and Role in Single-Site Technology 

Methylalumoxanes (MAO) have become important commercial products in the preparation of single-site catalysts for the manufactme of polyethylene. Therefore, a brief discussion on the preparation, structure and role of 

Alkylalumoxanes are oligomeric organometallic compoimds with the general formula  

Alkylalumoxane compounds became readily attainable in the late 1950s when alkylaluminum compounds were produced in relatively large quantities to support the Ziegler-Natta catalyst technology that had been discovered to provide a low-pressure route to polyethylene. Therefore, alkylalumoxane compounds were extensively studied in the 1960s as catalysts in the polymerization of epoxides, aldehydes and olefins [25], 

The preparation of alumoxanes is carried out by the slow, controlled hydrolysis of an aluminum alkyl with water to eliminate an alkane. An example of one such reaction is shown below utilizing an Al/water ratio of two, which results in a dimeric species. 

---