Homogeneous epoxidation of lipophilic alkenes by aqueous hydrogen peroxide: catalysis of a Keggin-type phosphotungstate-functionalized ionic liquid in amphipathic ionic liquid solution

Epoxidation of olefins with hydrogen peroxide catalyzed by a reusable lacunary-type phosphotungstate catalyst

“…1, Fresh PW 11 ; 2, recovered PW 11 ; 3, fresh PW 12 ; 4, recovered PW 12 . and 1047 cm 1 (PO), 952 cm 1 (WO d ), 894 cm 1 and 857 cm 1 (WO b W), 803 cm 1 and 730 cm 1 (WO c W), and was identical to that of [PW 11 O 39 ] 7 salts reported previously [17,24]. Elemental analysis data of PW 11 were also consistent with the expected structure.…”

“…31 P NMR spectra support this hypothesis. When PW 11 was treated with H 2 O 2 for only 30 min, it was rapidly degraded into the Venturello complex 3 , as shown by the appearance of a peak at 2.7 ppm in the 31 P NMR spectrum [15,28], while the original chemical shift at 10.7 ppm assigned to parent lacunary-type phosphotungstate anions [17,18,24] disappeared (Figures 3(1) and 3(2)). Furthermore, a new peak appeared around 15.3 ppm, which is characteristic of the Keggin-type structure (Figure 3(3)).…”

Epoxidation of Butadiene with Hydrogen Peroxide Catalyzed by the Salts of Phosphotungstate Anions: Relation Between Catalytic Activity and Composition of Intermediate Peroxo Complexes

“…salts of [PW11 O 39 ] 7anion. The motivation for this study was positive effect of imidazolium salts (ionic liquids) used as solvents in a number of peroxide reactions[13,[30][31][32][33][34][35].Commercial chemically pure H 3 [PW 12 O 40 ]ÁnH 2 O and H 3 PO 4 , (n-C 4 H 9 ) 4 NBr of a reagent grade, unstabilized *34% aqueous H 2 O 2 of special purity (Reachim), CH 3 CN of high purity (Kriochrom) and 1,3-butadiene (Aldrich) were used. Na 7 [PW 11 O 39 ] (Na-PW 11 ) was prepared as usual, by mixing H 3 [PW 12 O 40 ] and H 3 PO 4 aqueous solutions in atomic ratio P/W = 1/11 and adding Na 2 CO 3 to pH 4, with subsequent heating at 90°C for 1 h. 31 P NMR: a single peak -10.9 ppm [36](Fig.…”

Molybdovanadophosphoric anion ionic liquid as a reusable catalyst for solvent-free benzene oxidation to phenol by H2O2

“…After reaction, the catalyst was found to be self-precipitating, which made the recovery and reuse of the catalyst very convenient. Wang et al [30] [31], and employed as catalyst for esterification of various alcohols with acetic acid. This IL catalyst showed high activity and excellent esters yields.…”