Heterogenization of alkene epoxidation catalysts

Bibliographic Details
Main Author: Buffon,Regina
Publication Date: 2003
Other Authors: Schuchardt,Ulf
Format: Article
Language: eng
Source: Journal of the Brazilian Chemical Society (Online)
Download full: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532003000300002
Summary: This account describes our efforts to heterogenize epoxidation catalysts. Anchored and sol-gel entrapped molybdenum were shown to be very selective, but had a strongly reduced activity. On the other hand, molybdenum silicates were very active and stable as long as no diols were present in the reaction mixture. Heterogenized rhenium catalysts were less active but allowed the use of anhydrous hydrogen peroxide as oxidant. However, the high cost and difficult regeneration prevents the industrial use of these catalysts. During these investigations, we found that alumina alone is active in the epoxidation with anhydrous hydrogen peroxide, giving good conversions to epoxides with high selectivity. More research is needed in order to clarify the nature of the hydroxyl groups responsible for its catalytic activity and thus to produce an appropriate material which would allow the obtention of epoxides with high selectivity under industrial conditions.