(427h) Lipase-Mediated Epoxidation with Uhp in Ethyl Acetate
AIChE Annual Meeting
2006
2006 Annual Meeting
Food, Pharmaceutical & Bioengineering Division
Biocatalysis & Protein Engineering Poster Session
Wednesday, November 15, 2006 - 3:15pm to 5:45pm
The epoxidation of electron rich olefins is generally carried out using preformed peroxyacids or metal catalysts in the presence of stoichiometric amounts of hydrogen peroxide or tert-butyl hydroperoxide. The drawbacks of these methods include the high cost and toxicity of catalysts, environmental concerns of solvents and the potential side reactions at the harsh oxidizing conditions employed. A novel method for the perhydrolysis of carboxylic acids employs a lipase in the presence of hydrogen peroxide in an organic solvent at ambient conditions. In this study, this chemo-enzymatic reaction has been optimized using Novozyme 435, the immobilized form of the lipase from Candida antarctica, and the complex, Urea-Hydrogen Peroxide (UHP). The absence of water also minimizes further undesired reactions of the oxidized product. The amount of enzyme in the reaction mixture had little effect on the single run conversions. On recycling, the enzyme maintained its activity after five rounds of epoxidations. This contrasts with the rapid loss of activity when aqueous H2O2 was used as the oxidant. Several other alkenes, such as indene, were epoxidized by this method with yields ranging from 75 to 100%. The hydrolysis of these epoxides by microbial epoxide hydrolases affords the enantiomerically pure epoxides and diols. Studies are underway to integrate the lipase and hydrolase activities in a one pot reaction to yield the chiral products.