Solid solutions for cleaning up chemical processes using hydrogen peroxide

Abstract

Liquid phase oxidations with dioxygen are generally radical chain processes and the intermediate alkylperoxy and alkoxy radicals are largely indiscriminate in their reactivity. Selective oxidations are generally speaking, observed only with relatively small molecules containing one reactive group. This chapter is discusses the preparation and use of solid catalysts in the presence of H 2 O 2 for the manufacture of fine chemical and pharmaceutical intermediates. Several industrial processes, using H 2 O 2 , have been developed. For example, the oxidation of hydrogen cyanide (HCN) to cyanogen, the production of hydroquinone and catechol by the hydroxylation of phenol, the oxidation of ammonia to hydrazine, and the epoxidation of natural oils. However, the majority of synthetic routes developed to date rely upon the homogeneous activation of H 2 O 2 . The work presented in the chapter is based on the studies carried out, either in-house or via externally sponsored research. The most common, accessible, and investigated class of polyoxometalates are relatively robust to thermal decomposition. A considerable amount of homogeneous chemistry has been carried out in the subsequent experiments in the presence of aqueous H 2 O 2 . However, researchers have been interested for sometime in the oxygen transfer ability of immobilized polyoxometalates in the presence of H 2 O 2 . The two complexes that have been paid most attention were ammonium molybdate and phosphotungstic acid, supported onto a cross-linked polystyrene anionic resin and γ-alumina, respectively.