Xerogel-Sequestered Silanated Organochalcogenide Catalysts for Bromination with Hydrogen Peroxide and Sodium Bromide

Molecules

Caitlyn M. Gatley¹  Lisa M. Muller¹  Meredith A. Lang²  Eduardo E. Alberto²  Michael R. Detty¹ 

[1] Department of Chemistry, The State University of New York at Buffalo, Buffalo, NY 14260, USA;

关键词: organoselenides;    organotellurides;    diorgano diselenides;    xerogel;    catalytic bromination;   

DOI  :  10.3390/molecules20069616

来源: mdpi

【 摘 要 】

While H₂O₂ is a powerful oxidant, decomposing into environmentally benign H₂O and O₂, a catalyst is often required for reactions with H₂O₂ to proceed at synthetically useful rates. Organotellurium and organoselenium compounds catalyze the oxidation of halide salts to hypohalous acids using H₂O₂. When sequestered into xerogel monoliths, the xerogel-chalcogenide combinations have demonstrated increased catalytic activity relative to the organochalcogen compound alone in solution for the oxidation of halide salts to hypohalous acids with H₂O₂. Diorganotellurides, diorganoselenides, and diorganodiselenides bearing triethoxysilane functionalities were sequestered into xerogel monoliths and their catalytic activity and longevity were investigated. The longevity of the catalyst-xerogel combinations was examined by isolating and recycling the catalyst-xerogel combination. It was found tellurium-containing catalyst 3 and selenium-containing catalyst 8 maintained their catalytic activity through three recycling trials and adding electron-donating substituents to catalyst 3 also increased the catalytic rate. The presence of organotellurium and organoselenium groups in the +4 oxidation state was determined by X-ray photoelectron spectroscopy.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.