Alkyl and aryl peracids have been incorporated onto silica materials either by sol-gel synthesis or by grafting of nitrile or ester groups, which were subsequently hydrolyzed and oxidized.  These materials have been characterized by FTIR, TGA, solid-state NMR, and iodometric determination of peracid content.  The peracid-modified silicas were evaluated as oxygen transfer agents for the epoxidation of linear and cyclic alkenes (e.g. n-octene, cyclohexene, cyclooctene and styrene).  The use of sol-gel materials resulted in better selectivity towards epoxide formation compared to grafted materials.  The higher surface density of silanols in the latter may have contributed to the ring-opening of the epoxides into the diols.  We can tune the selectivity and throughput of our heterogeneous oxidants by varying key parameters such as the structure and surface density of the peracids, as well as the structure and surface density of silanol-capping moieties.  In addition, these organic-inorganic hybrid materials are advantageous for ease of handling and separation of products, can be regenerated, and can be readily adapted for either batch or flow systems.

Peracid-modified silica as heterogeneous oxygen transfer agents

245th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.