Immobilization systems allylic activation

The heterogeneous catalytic system iron phthalocyanine (7) immobilized on silica and tert-butyl hydroperoxide, TBHP, has been proposed for allylic oxidation reactions (10). This catalytic system has shown good activity in the oxidation of 2,3,6-trimethylphenol for the production of 1,4-trimethylbenzoquinone (yield > 80%), a vitamin E precursor (11), and in the oxidation of alkynes and propargylic alcohols to a,p-acetylenic ketones (yields > 60%) (12). A 43% yield of 2-cyclohexen-l-one was obtained (10) over the p-oxo dimeric form of iron tetrasulfophthalocyanine (7a) immobilized on silica using TBHP as oxidant and CH3CN as solvent however, the catalyst deactivated under reaction conditions. 

TiCl4 immobilized on surface of PE modified by graft polymerization of vinylpyridine, acrylonitrile, methyl vinyl ketone, allyl alcohol, allylamine, allyl sulfide or acrylic acid, has been studied with IR spectroscopy and XPS I166J. Cluster aggregates of Ti(IV) fixed on the surface, were discovered. Their formation did not cause the reduction of Ti(IV). In binary catalytic systems of Ti(IV) on an organo-aluminum polymeric support, Ti(IV) was reduced to Ti(III), and Ti(II) appeared at 343 K. The high and stable activity of immobilized titanium compounds during ethylene polymerization was attributed to deceleration of Ti(IV) reduction processes. 

---