Methylalumoxane – History, Production, Properties, and Applications (Eur. J. Inorg. Chem. 1/2015)

Abstract

The cover picture shows the birth of methylalumoxane MeAlO (MAO), or at least one of the possible MAO species, by reaction of trimethylaluminum with water. MAO is the cocatalyst of choice in Ziegler–Natta type olefin polymerization catalysis and is therefore produced in bulk quantities. Interestingly, it is also a compound shrouded in mystery and subject to significant controversy. This is the first comprehensive review article dealing with all aspects of MAO. Details are presented in the Microreview by H. S. Zijlstra and S. Harder on . For more on the story behind the cover research, see the .

Tuning Bis(imino)pyridyl Iron‐Catalyzed Ethylene Oligomerization by Modification of MAO with p‐BrPhOH

“…In our catalytic system, MAO is most expensive and takes the majority of the cost, which is another major restriction for its commercialization. [20] Thus, the yield of α-olefins relative to unit mass of MAO is of great significance. Table 4 summarizes the polymerization results for the runs undertaken at different molar ratios of [Al]/[Fe] while with the fixed dosage of MAO.…”

Alternative aluminum-based cocatalysts for the iron-catalyzed oligomerization of ethylene

“…j K not determined, a short distribution of oligomers was observed (see text). 1 H NMR spectroscopy revealed, after addition of a diol such as 11 to AlMe 3 at -70 °C in deuterated benzene, broad signals between 0.1 and -0.3 ppm that may be attributed to organoaluminum oligomers 12 and sharp singlets at -0.12, -0.34 and -0.79 ppm that were attributed to the trinuclear aluminum complex 16 (Figure 3), by comparison with an authentic sample prepared according to the literature. 13 Using a similar procedure, the reaction of 2,2'-biphenol with AlMe 3 led to a new compound, characterized by 1 …”

On the Nature of the Lewis Acidic Sites in “TMA‐Free” Phenol‐Modified Methylaluminoxane

“…Methylaluminoxane (MAO), the product of the controlled hydrolysis of trimethylaluminum (TMA), is the archetypical cocatalyst in molecular olefin polymerization catalysis. [1,2] Although its excellent alkylating, abstracting and impurity scavenging properties have been widely recognized, [1][2][3][4] its structure remains quite elusive. This is due to the fact that MAO does not exist as a discrete molecule, but rather as a complex multi-component system, constituted of a distribution of oligomeric (AlOMe) n cages and some residual TMA.…”