Photo-oxidation of di-n-butylsulfide by various electron transfer sensitizers in oxygenated acetonitrile.

The selective activation of different photosensitizers has been carried out under comparable conditions and their efficiency towards di-n-butylsulfide oxidation in oxygenated acetonitrile compared from the product distribution after 150 minutes of irradiation. As expected, the best selectivity towards sulfoxide is obtained with a conventional energy transfer sensitizer such as Rose Bengal (RB), but also with a quinone with a low-lying triplet state, 2,3,5,6-tetrachloro-1,4-benzoquinone (chloranil or CHLO) and with 9,10-dicyanoanthracene (DCA). More significant yields in sulfonic and sulfuric acids are obtained under sensitization with 9,10-anthraquinone (ANT) or a derivative of benzophenone, 4-benzoyl benzoic acid (4-BB), with which additional experiments were carried out in order to discuss the involvement of either singlet oxygen or superoxide radical anion.