Direct epoxidation of olefins catalyzed by heteropolyoxometalates with molecular oxygen and recyclable reductant

A new epoxidation system is reported in this communication. Heteropolyoxometalates catalyst/recyclable reductant 2-ethylanthrahydroquinone/O-2 is employed for epoxidation of olefins. The reductant can be regenerated by catalytic hydrogenation without consumption. (C) 2001 Elsevier Science B.V. All rights reserved.

Simultaneous and ultrarapid determination of reactive oxygen species and reduced glutathione in apoptotic leukemia cells by microchip electrophoresis

A microchip electrophoresis method coupled with laser-induced fluorescence (LIF) detection was established for simultaneous determination of two kinds of intracellular signaling molecules (reactive oxygen species, ROS, and reduced glutathione, GSH) related to apoptosis and oxidative stress. As the probe dihydrorhodamine-123 (DHR123) can be converted intracellularly by ROS to the fluorescent rhodamine-123 (Rh123), and the probe naphthalene-2,3-dicarboxaldehyde (NDA) can react quickly with GSH to produce a fluorescent adduct, rapid determination of Rh-123 and GSH was achieved on a glass microchip within 27 s using a 20 mm borate buffer (pH 9.2). The established method was tested to measure the intracellular ROS and GSH levels in acute promyelocytic leukemia (APL)-derived NB4 cells. An elevation of intracellular ROS and depletion of GSH were observed in apoptotic N134 cells induced by arsenic trioxide (AS(2)O(3)) at low concentration (1-2 mu m). Buthionine sulfoximine (BSO), in combination with AS(2)O(3) enhanced the decrease of reduced GSH to a great extent. The combined treatment of AS(2)O(3) and hydrogen peroxide (H2O2) led to an inverse relationship between the concentrations of ROS and GSH obtained, showing the proposed method can readily evaluate the generation of ROS, which occurs simultaneously with the consumption of the inherent antioxidant.

Development and application of oxygen permeable membrane in selective oxidation of light alkanes

In this paper, oxygen permeable membrane used in membrane reactor for selective oxidation of alkanes will be discussed in detail. The recent developments for the membrane materials will be presented, and the strategy for the selection of the membrane materials will be outlined. The main applications of oxygen permeable membrane in selective oxidation of light alkanes will be summarized, which includes partial oxidation of methane (POM) to syngas and partial oxidation of heptane (POH) to produce H-2, oxidative coupling of methane (OCM) to C-2, oxidative dehydrogenation of ethane (ODE) to ethylene and oxidative dehydrogenation of propane (ODP) to propylene. Achievements for the membrane material developments and selective oxidation of light alkanes in membrane reactor in our group are highlighted.