Latex Supported Manganese(III) Porphyrin Catalysts for Oxidations of Alkenes by Hydrogen Peroxide and {\it tert-} Butyl Hydroperoxide in the Aqueous Medium

Authors: Hayrettin TÜRK

Abstract: Cationic polymer latexes were prepared by emulsion copolymerization of vinylbenzyl chloride and divinylbenzene followed by quaternization with trimethylamine and used as catalyst supports for 5,10,15,20-tetrakis(2, 6-dichloro-3-sulfonatophenyl)porphinatomanganese(III) chloride and 5,10,15,20-tetra(4-sul- fonatophenyl)porphinatomanganese(III) chloride. The supported catalysts and water soluble analogues were used for oxidation of styrene, 1-decene and {\it cis}-cyclooctene by hydrogen peroxide and {\it tert}- butyl hydroperoxide in the aqueous phase. The oxidation of 1-decene and {\it cis}-cyclooctene failed. In the oxidation of styrene, the porphyrin catalysts in the latex were more active than in solution. The relative molar ratios of oxidant: styrene: Mn porphyrin were 1250: 750: 1, and about 25\% styrene conversion in 4 h was obtained. When hydrogen peroxide was employed as oxidant, styrene oxide and benzaldehyde were the major and minor products, respectively, and in the case of {\it tert}-butyl hydroperoxide, it was vice versa. The reaction depended on pH, the porphyrin ligand, type of oxidant used and presence of imidazole.


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