Abstract
A series of Fe-Ba mixed oxides, including a pure Fe-containing sample as a reference, have been synthesized via a sol-gel process using Fe(3+) or Fe(2+) salts and BaSO(4) as raw materials, with Pluronic P123 serving as a template. These oxides have been thoroughly characterized and subsequently utilized as catalysts for the chlorination of various organic molecules. Commercial hydrochloric acid, known for its relative safety, and environmentally friendly aqueous hydrogen peroxide were employed as the chlorine source and oxidant, respectively. The pure Fe-containing catalyst displays excellent thermal stability between 600 and 800 °C and exhibited moderate to high conversions in the chlorination of toluene, benzene, and tert-butyl hydroperoxide, with remarkable ortho-selectivity in chlorination of toluene. The combination of Fe(3+) salt with BaSO(4) in the sol-gel process results in a Fe-Ba mixed oxide catalyst composed of BaO(2), BaFe(4)O(7), and Fe(2)O(3), significantly enhancing the chlorination activity compared to that displayed by the pure Fe catalyst. Notably, the chlorination of tert-butyl hydroperoxide (TBHP) does not require additional oxidants such as H(2)O(2), and involves both electrophilic substitution and nucleophilic addition. Notably, the chlorination of bromobenzene yields chlorobenzene as the sole product, a transformation that has not been previously reported. Overall, this catalytic chlorination system holds promise for advancing the chlorination industry and enhancing pharmaceutical production.