Abstract
The acidic properties of EtAlCl
2 are significantly enhanced by the addition of O
2 · O
2 interaction with EtAlCl
2 initiates the cationic polymerization of
cis-2-butene, the oxidation of naphthalene to the corresponding radical cation; it also favors the complexation of the Lewis acid to the metathesis catalyst W(CO)
5PPh
3, and thus promotes the catalytic activity of this complex in metathesis reactions. It is suggested that O
2 increases the electron affinity of alkylaluminium compounds. The promoting effect of O
2 in metathesis, observed by various authors, is therefore explained on the basis of Lewis acidity.