OXIDATION OF ALKENES IN SUPERCRITICAL CARBON-DIOXIDE CATALYZED BY MOLYBDENUM HEXACARBONYL

In supercritical CO2, olefin oxidation to epoxides or diols using a Mo (CO)(6) catalyst precursor and using t-BuOOH as oxidant proceeds in ne arly quantitative yields. The highest yields and fastest rates of diol and epoxide formation were observed with cis-alkenes, while trans-alk enes were considerably less reactive. Phenyl-substituted olefins show a tendency to cleave to their corresponding aldehyde. The use of 70 wt % aqueous solutions of tert-butyl hydroperoxide yield the trans-diol, while anhydrous decane solutions of t-BuOOH give the epoxide. Clearly Mo(CO)(6) proved to be the most effective oxygen transfer catalyst fo r these reactions. Several other oxygen transfer catalysts were tested but proved to be less effective under these conditions. An autoclave equipped with quartz windows allowed for the qualitative determination of a homogeneous reaction environment in the supercritical fluid.