Autooxidation of cumene catalyzed by transition metal compounds on polymeric supports

The autooxidation of cumene to cumene hydroperoxide (CHP) in the presence of a supported catalyst was investigated. When Cu(OAc)2 was supported on Chelex, polyvinylpyridine or SiO2, it was demonstrated that polyvinylpyridine and SiO2 are poor supports for a catalyst in cumene autooxidation. Several metal ions supported on Chelex were tested for their effectiveness in initiating cumene autooxidation at 353 K. The rate of autooxidation follows the order Mn(II) > Cu(II) > Co(II) > Ni(II) > Fe(II). However, Mn(II) gives a poor selectivity to CHP as it can also catalyze the conversion of CHP to 2-phenyl-2-propanol. The most suitable catalyst in the steady propagation of cumene autooxidation has the composition of Cu(OAc)2 (0.6 mmol) on dried Chelex (1.0 g), denoted Cu(OAc)2-CHX-0.6. There is an optimal ratio of Cu(OAc)2-CHX-0.6 to substrate (0.2 g per 10 ml cumene) to achieve an autooxidation rate that is 63% greater than that initiated with CHP at 353 K. The selectivity to CHP is also greater. This ratio is also the best for the rate of initiation in cumene autooxidation to CHP. The lifetime of this catalyst is long; no sign of deactivation was observed in our experiments.