Kinetics and Mechanism of the Epoxidation of Allylic Alcohols by Hydrogen Peroxide, Catalyzed by Methyltrioxorhenium
Author | : Heather Anne Riley |
Publisher | : |
Total Pages | : 100 |
Release | : 1998 |
ISBN-10 | : OCLC:40427367 |
ISBN-13 | : |
Rating | : 4/5 (67 Downloads) |
Download or read book Kinetics and Mechanism of the Epoxidation of Allylic Alcohols by Hydrogen Peroxide, Catalyzed by Methyltrioxorhenium written by Heather Anne Riley and published by . This book was released on 1998 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: Allylic alcohols were oxidized using hydrogen peroxide as an oxygen source and methyltrioxorhenium (MTO) as catalyst. Hydrogen peroxide and MTO react to form 1:1 and 2:1 rhenium peroxides, denoted as A and B, respectively. The bisperoxide species, B was the reactive form of the catalyst. The rate constants for the oxidation of the allylic alcohols were evaluated using pseudo-first-order techniques and were slower than the corresponding alkenes. An unexpected dependence of the rate constant on [H202] was found for fast-reacting substrates. A mechanism featuring H-bonding of the allylic alcohol with a peroxidic oxygen of the catalyst is proposed. Kinetic measurements with added pyridine N-oxide showed that the rate constants initially decrease with increasing pyridine N-oxide concentration, reach a minimum, and then increase, finally surpassing that of the experiment without pyridine N-oxide.