938-09-0Relevant articles and documents
Remarkable efficiency of iron(III) versus manganese(III) tetraphenylporphyrins as catalysts for fast and quantitative oxidation of sulfides into sulfones by hydrogen peroxide
Marques, Antonio,Di Matteo, Massimo,Ruasse, Marie-Francoise
, p. 770 - 775 (1998)
The efficiency of various metallo-phtalocyanines (Pht) and - tetraphenylporphyrins (TPP) as catalysts for the H2O2 oxidations of dibenzylsulfide, phenylchloroethylsulfide, and thioanisole is investigated in ethanol and acetonitrile, using imidazole as a cocatalyst. Neither PhtNi(II) nor TPPCo(II) exhibits any catalytic activity. PhtMn(II) and TPPMn(III)Cl accelerate markedly these reactions but do not promote quantitative oxidations, at most 70% of the sulfides being transformed into sulfoxides. In contrast, with PhtFe(II) sulfoxides are obtained with a 100% yield from sulfides. Finally, the only catalyst able to oxidize sulfides rapidly (5 min), completely and quantitatively (100% sulfone) is TPPFe(III)Cl in EtOH. The absence of any by-product, disulfide in particular, suggests that a free sulfenium radical cation is not an active intermediate in these reactions. The marked differences in the behaviour of TPPMn(III)Cl and TPPFe(III)Cl are analyzed by comparing the rates of the catalyst decomposition, of the sulfoxide and sulfone formation as a function of the hydrogen peroxide concentration. The results are discussed in terms of a competition between the several oxidative pathways and a possible mechanism for the oxygen transfer to sulfides.
By means of a micro channel reactor method of preparing sulfoxide or sulfone
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Paragraph 0090-0094, (2017/04/11)
The invention discloses a method for preparing sulfoxide or sulfone by using a micro-channel reactor. The invention provides a method for preparing sulfoxide or sulfone. The method comprises the following steps: respectively feeding a homogeneous solution prepared from thioether 1 and a solvent, and an oxidant into the micro-channel reactor, and contacting the homogeneous solution with the oxidant in a micro-channel for oxidation reaction so as to obtain sulfoxide or sulfone, wherein the oxidation reaction time is 1-300 seconds. The method disclosed by the invention is very short in reaction time, precise in reaction condition control, high in security, applicable to rapid preparation of kilogram-scale products and capable of realizing continuous production; the sulfoxide and sulfone are high in selectivity, high in yield, good in purity and applicable to on-scale industrial production.
Optically active tripodal dendritic polyoxometalates: Synthesis, characterization and their use in asymmetric sulfide oxidation with hydrogen peroxide
Jahier, Claire,Coustou, Marie-Flora,Cantuel, Martine,McClenaghan, Nathan D.,Buffeteau, Thierry,Cavagnat, Dominique,Carraro, Mauro,Nlate, Sylvain
experimental part, p. 727 - 738 (2011/04/26)
A series of structurally well-defined enantiopure tripodal allyl dendritic structures bearing three amine groups have been synthesized. The hydrogenation of the allyl groups in the presence of a Pd/C catalyst gave the corresponding enantiopure n-propyl counterparts. Treatment of these n-propyl amino dendrimers with heteropolyacid H3PW12O40 and excess H 2O2 gave the enantiopure n-propyl {PO 4[WO(O2)2]4}3- salts. Characterization of these dendritic POM hybrids in solution by NMR spectroscopy, elemental analysis, UV/Vis spectrophotometry, circular dichroism (CD), vibrational circular dichroism (VCD) and fluorimetry indicates the presence of POM-ligand interactions and confirms their optical and chiroptical properties. The hybrid compounds selectively oxidized sulfides to the corresponding chiral sulfoxides with up to 13% enantiomeric excess (ee), highlighting the transfer of chirality from the dendritic wedges to the inorganic cluster. The properties of the POM anion, especially its solubility and regio-and stereoselectivity, are sensitive to the structure of the cation. The catalyst was recovered by precipitation without any discernible loss in activity, selectivity or enantioselectivity over three catalytic cycles at-50 °C. Interestingly, a dendritic effect was noted in the enantioselectivity as the dendritic-POM hybrids are more selective than their non-dendritic counterparts. The ee resulting from chirality transfer to the anionic POM unit is comparable to that obtained in our previous work with monopodal dendritic polyoxometalates (14%) despite the polyvalency of the highly charged tripodal ligand, which is rationalized by different spectroscopic methods. Copyright
