Tungstate catalyzed epoxidation

EFFECT OF CARBOXYLIC ACIDS AS COCATALYSTS IN TUNGSTATE-CATALYZED EPOXIDATIONS... 

One problem associated with the peroxotungstate-catalyzed epoxidation system described above is the separation of the catalyst after the completed reaction. To overcome this obstacle, efforts to prepare heterogeneous tungstate catalysts have been conducted. De Vos and coworkers employed W catalysts derived from sodium tungstate and layered double hydroxides (LDH - coprecipitated MgCU, AICI3, and NaOH) for the epoxidation of simple olefins and allyl alcohols with... 

Hydrogen peroxide is a particularly attractive oxidant and holds a prominent position in the development of benign catalytic oxidation procedures. In recent years a number of highly versatile catalytic oxidation methods based on, for example, polyoxometalates [154], methyltrioxorhenium [155] or tungstate [4, 156] complexes in the presence of phase transfer catalysts, all using hydrogen peroxide as the terminal oxidant, have been introduced. Mn-catalyzed epoxidations, aldehyde... 

H. Shi, X. Wang, R. M. Hua, Epoxidation of alpha, beta-imsaturated acids catalyzed by tungstate (VI) or molybdate (VI) in aqueous solvents a specific direct oxygen transfer mechanism. Tetrahedron 61 (2005) 1297. 

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