Oxidation of sulfides to sulfoxides mediated by ionic liquids

Abstract

A highly selective and efficient oxidation of sulfides to sulfoxides is presented. The reactions were carried out at room temperature in the absence of a catalyst in the ionic liquid [Bmim][BF 4 ] (Bmim = 1-butyl-3-methylimidazolium) using aqueous H 2 O 2 (35%) as oxidant. The products were obtained in high yields. Compared to the analogous reactions in organic solvents, this system can be recycled without significant loss of activity and selectivity. Additionally, the reaction mechanism was examined by IR, Raman and NMR spectroscopy. Based on these examinations, it appears that the crucial step during the oxidation procedure is the formation of a hydrogen bond between the ionic liquid and the oxidant.

Oxidation Reactions Catalyzed by Polyoxomolybdate Salts

“…All solvents were collected from purification systems and kept over molecular sieves. 1 H NMR, 13 C NMR and 31 P NMR spectra were recorded on a Bruker Avance DPX-400 spectrometer. IR spectra were recorded on a Varian FTIR-670 spectrometer, using a GladiATR accessory with a diamond ATR element.…”

“…For the recycling experiment, ethyl acetate was added to the reaction mixture after the reaction was completed and the catalyst precipitated, filtered off, washed with ethyl acetate, and dried in high vacuum at room temperature. All products were characterized by melting point, 1 H NMR, 13 C NMR and IR spectroscopy (see Supporting Information).…”

Epoxidation of Olefins Catalyzed by Polyoxomolybdates Formed in-situ in Ionic Liquids

“…There is a bulging need for the elaboration of catalytic systems that consume only cheap, ecologically friendly and readily available oxidants, such as hydrogen peroxide [3,4]. In this context our group reported very recently about the ability of certain anions of ionic liquids, such as tetrafluoroborate and perrhenate, to activate hydrogen peroxide through only hydrogen bonding interactions [5,6]. Olefin epoxidation with imidazolium perrhenates occurs via an outer-sphere mechanism, not involving the Re center [6].…”

Extractive oxidative desulfurization of model oil/crude oil using KSF montmorillonite-supported 12-tungstophosphoric acid

“…There are some disadvantages of these reported systems (compared with our system) such as long reaction time, high reaction temperature or large amount of catalyst and using ionic liquids as additives. The mechanism of the catalytic desulfurization process (Scheme 2) is assumed to include the following steps: (1) 3-by H 2 O 2 ; (4) transformation of PW 4 into PW 12 species with free tungsten species, after the desulfurization (Zhang et al 2012a, b).…”

“…Previous reports have demonstrated the effective catalytic performances of supported HPAs for the oxidation of thiophene (T) and its derivatives with different oxidants (Hui-Peng et al 2007;Kukovecz et al 2002;Yan et al 2009b). However, most of the research up to now has investigated homogenous or amphiphilic catalysts and oxidants (Gao et al 2006;Zhang et al 2012a, b;Maity et al 2009;Qiu et al 2009;Xue et al 2012;Bhutto et al 2016). In these systems, the catalysts are usually dissolved in the continuous phase or inside the emulsion droplets; thus, it is difficult to separate the catalysts and recycle them from the emulsion systems.…”