35539-61-8Relevant academic research and scientific papers
Oxidation of thioethers and sulfoxides with hydrogen peroxide using TS-1 as catalyst
Hutchings,Lee,McMorn,Page,Robinson,Willock,Davies,Watson,McGuire,Lee,Bethell
, p. 1523 - 1529 (2007/10/03)
A combined experimental and molecular simulation study of the oxidation of thioethers with H2O2 was conducted using titanium-containing zeolites as catalysts. Regioselectivity was investigated for the oxidation of allyl methyl thioether using TS-1 as catalyst. Only products for the oxidation of sulfur, such as sulfoxide and sulfolane, were found. Shape-selective oxidation was studied with four isomeric butyl methyl thioethers. For n-, iso-, and sec-butyl methyl thioethers, the principal product for the TS-1 catalyzed reaction was the sulfone, but that for tert-butyl methyl thioether was from partial oxidation to sulfoxide. The origin of this effect was evaluated using molecular simulations. Thioether oxidation to sulfoxide readily occurred via a non-catalyzed solution reaction, while the oxidation of sulfoxide to sulfone was only observed in the catalyzed reactions. The non-catalyzed reaction can be suppressed by conducting the catalyzed reaction in the presence of a base, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), that is too large to diffuse into the intracrystalline pore structure of TS-1. With DBU, the reaction rate with TS-1 as catalyst was much lower. The relative ratios of the sulfoxide and sulfone products can be elucidated through intramolecular steric hindrance and the shape selectivity of the zeolite. TS-1 has been used for the oxidation of alkenes, alcohols, allylic alcohols, phenols, and benzene.
