Ishii-Venturello system

The major limitation of the potential value of the Venturello-Ishii systems, however, is related to the use of toxic and industrially undesirable chlorinated solvents , defeating the environmental advantages of H2O2 as primary oxygen source . In this respect, the PCWP catalytic system was modified by using t-butyl alcohol as solvent and by... 

The tetra-n-hexylammonium (THA) salt of [P04 W0(02)2 4]3- was isolated and characterized crystallographically by Venturello and coworkers [77]. The anion consisted of the P043 and two [W202(02)4] species. As mentioned above, [P04 W0(02)2 4]3 has been postulated to be a catalytically active species for the H3[P i204 )]/H202 system developed by Ishii and coworkers [35-44] because P04[W0(02)2 4]3 exhibited a very similar catalytic activity and selectivity to those of the Ishii system [77, 78]. 

This allyhc oxidation can be suppressed by working with the hpophihc catalyst C. Hydrophobic olefins such as cydooctene are expected to interact favorably with the aromatic p-tosylate on the peroxoW-LDH surface. The transfer of the electrophihc oxygen to the olefin then takes place in an essentially hydrophobic compartment of the reaction system, as in the Venturello-Ishii reactions. In such an environment the olefin is enriched with respect to hydrogen peroxide and this improves the effidency of the oxidant use. Another potential advantage of our system C is that there is no need for a chlorinated solvent to constitute a second, apolcir hquid phase. 

INVESTIGATION OF THE MECHANISM OF THE VENTURELLO-ISHII EPOXIDATION SYSTEM... 

---