Creation of a chain-like cationic iron species in montmorillonite as a highly active heterogeneous catalyst for alkane oxygenations using hydrogen peroxide

A chain-like Fe3+ species containing an Fe-O-Fe unit has been prepared within the interlayer space of a montmorillonite, which showed a very high catalytic activity (turnover frequency 386 h-1 and turnover number 23,200) for the oxidation of cyclohexane with H2O2, affording cyclohexyl hydroperoxide as a major product.     

Capillary electrophoresis with laser induced-fluorescence detection of profens derivatized with the water-soluble fluorogenic reagent 4-N-(4-N'-aminoethyl)piperazino-7-nitro-2,1,3-benzoxadiazole

Profens, including pranoprofen, fenoprofen, flurbiprofen, ketoprofen and ibuprofen (Ib), were derivatized by a water-soluble benzofurazan fluorescent reagent, 4-N-(4-N'-aminoethyl)piperazino-7-nitro-2,1,3-benzoxadiazole and then were run on capillary electrophoresis in a NH4Ac-HAc buffer of pH 3.1 containing 2.4 mM beta-cyclodextrin. At room temperature, the derivatization reaction was catalyzed by triphenyl phosphine and diphenyl disulfide in acetonitrile medium, and the derivatives fluoresce around 530 nm when excited at 488 nm. With the CE running on a 50 cm x 50 microm I.D. length fused-silica capillary of by using Ar+ laser induced-fluorescence detection, the detection limits attained were in the range of 0.16 to 0.3 fmol.     

Hydroxyapatite-bound cationic ruthenium complexes as novel heterogeneous lewis acid catalysts for Diels-Alder and aldol reactions

Creation of a stable and well-defined active center on a solid surface is a promising protocol for designing more efficient hybrid-catalysts that bridge the gap between homogeneous and heterogeneous catalysis. Treatment of a hydroxyapatite-bound Ru complex (RuHAP) with an aqueous solution of AgX (X = SbF6-, TfO-) afforded a new type of cationic Ru phosphate complex, having potentially vacant coordination sites. These cationic RuHAPs exhibited Lewis acidity toward carbonyl and cyano groups, promoting Diels-Alder and Aldol reactions with high efficiencies. Moreover, no Ru leaching was detected in the above organic reactions, and then the catalysts were recyclable.     

Thermal conductivity of mixed alkali silicate glasses at low temperature

Thermal conductivity of glass is one of the fundamental properties of it. However, that has not been studied enough. That of only less than 20 compositions has been measured below the room temperature. In this study, we measured the thermal conductivity of xNa₂O · (100 ? x)SiO₂ and (33 ? y)Na₂O · yCs₂O · 67SiO₂ glasses by a transient heating method in the temperature range from about 150 K to room temperature. The conductivity of xNa₂O · (100 ? x)SiO₂ is found to decrease with the increase in alkali content. The dominant factor of this behavior is the decrease in phonon mean free path, which is due to the increase of non-bridge oxygen. Thermal conductivity of (33 ? y)Cs₂O · yNa₂O · 67SiO₂ is decreased with the increase in Cs₂O/(Na₂O + Cs₂O) ratio. The dominant factor of this behavior is the decrease of sound velocity. However, composition dependence of the phonon mean free path also affects the thermal conductivity. Phonon mean free path of 33Cs₂O · 67SiO₂ glass is longer than that of 33Na₂O · 67SiO₂ glass, and should be related to the change in distribution of structural unit in glass. In addition, phonon mean free path of mixed alkali glasses are shorter than that of single alkali glasses.