The performances of heterogeneous catalysts can be effectively tuned by changing the catalyst structures.Here we report a controllable nitrile synthesis from alcohol ammoxidation,where the nitrile hydration side react...The performances of heterogeneous catalysts can be effectively tuned by changing the catalyst structures.Here we report a controllable nitrile synthesis from alcohol ammoxidation,where the nitrile hydration side reaction could be efficiently prevented by changing the manganese oxide catalysts.α-Mn_(2)O_(3)based catalysts are highly selective for nitrile synthesis,but MnO_(2)-based catalysts includingα,β,γ,andδphases favour the amide production from tandem ammoxidation and hydration steps.Multiple structural,kinetic,and spectroscopic investigations reveal that water decomposition is hindered onα-Mn2O3,thus to switch off the nitrile hydration.In addition,the selectivity-control feature of manganese oxide catalysts is mainly related to their crystalline nature rather than oxide morphology,although the morphological issue is usually regarded as a crucial factor in many reactions.展开更多
Di-O-acetyl sucrose was regioselective synthesized by using dibutyltin oxide in about 60% yield. The structure of acetyl derivative was elucidated by 1H NMR, 13C NMR, 2D-NMR and MS spectral data.
Ethylene oxide(EO) and propylene oxide(PO) random copolyethers were synthesized by the sequential addition of the mixture of ethylene oxide and propylene oxide to propylene glycol (initiator) in the presence of potass...Ethylene oxide(EO) and propylene oxide(PO) random copolyethers were synthesized by the sequential addition of the mixture of ethylene oxide and propylene oxide to propylene glycol (initiator) in the presence of potassium hydroxide(KOH), and characterized with infrared spectrum(FTIR) and nuclear magnetism resonance(NMR). The effects of catalyst concentration, reaction temperature, charging rate and EO/PO mixture ratio on the polymerization reaction were investigated. It was revealed that the optimal reaction condition is the ratio of 2.5∶1 000(KOH mass vs. product mass), at 114.6℃ and pressure below 0.4 MPa. The residual KOH was neutralized by phosphoric acid(H 3PO 4). Then the crude copolyether was refined with adsorbents, and the refined copolyether, which contains less than 0.7 μg/ml K+, was obtained as colorless, viscous liquid.展开更多
In the present study, we investigated the role of reactive oxygen species（ROS） elevation induced by an anti-diabetic vanadium compound, vanadyl acetylacetonate（VO（acac）2）, in the regulation of lipolysis and gluc...In the present study, we investigated the role of reactive oxygen species（ROS） elevation induced by an anti-diabetic vanadium compound, vanadyl acetylacetonate（VO（acac）2）, in the regulation of lipolysis and glucose metabolism using differentiated 3T3L1 adipocytes as a model system. By confocal laser scanning microscopy, we found that VO（acac）2 induced ROS generation under high glucose stimulation, and the pretreatment of NADPH oxidase inhibitors could significantly reduce the elevated ROS level. Meanwhile, the decreased phosphorylated levels of AKT and the two key modulators of lipolysis（HSL and perilipin） were observed by western blot analysis. We also found that the contents of glycerol release were further reduced as well. In addition, the levels of key regulatory proteins, AS160 and GSK3β, in glucose metabolism pathway were correspondingly reduced. These findings demonstrated that ROS induced by vanadium compounds could act as a metabolic signal to activate AKT pathway to inhibit lipolysis and promote glucose transport and glycogen synthesis rather than by direct action by themselves. Our study contributed to elucidate the anti-diabetic effects of vanadium compounds and provided a theoretical basis for the further development of new vanadium complexes in the prevention and therapeutics of diabetes.展开更多
文摘The performances of heterogeneous catalysts can be effectively tuned by changing the catalyst structures.Here we report a controllable nitrile synthesis from alcohol ammoxidation,where the nitrile hydration side reaction could be efficiently prevented by changing the manganese oxide catalysts.α-Mn_(2)O_(3)based catalysts are highly selective for nitrile synthesis,but MnO_(2)-based catalysts includingα,β,γ,andδphases favour the amide production from tandem ammoxidation and hydration steps.Multiple structural,kinetic,and spectroscopic investigations reveal that water decomposition is hindered onα-Mn2O3,thus to switch off the nitrile hydration.In addition,the selectivity-control feature of manganese oxide catalysts is mainly related to their crystalline nature rather than oxide morphology,although the morphological issue is usually regarded as a crucial factor in many reactions.
文摘Di-O-acetyl sucrose was regioselective synthesized by using dibutyltin oxide in about 60% yield. The structure of acetyl derivative was elucidated by 1H NMR, 13C NMR, 2D-NMR and MS spectral data.
文摘Ethylene oxide(EO) and propylene oxide(PO) random copolyethers were synthesized by the sequential addition of the mixture of ethylene oxide and propylene oxide to propylene glycol (initiator) in the presence of potassium hydroxide(KOH), and characterized with infrared spectrum(FTIR) and nuclear magnetism resonance(NMR). The effects of catalyst concentration, reaction temperature, charging rate and EO/PO mixture ratio on the polymerization reaction were investigated. It was revealed that the optimal reaction condition is the ratio of 2.5∶1 000(KOH mass vs. product mass), at 114.6℃ and pressure below 0.4 MPa. The residual KOH was neutralized by phosphoric acid(H 3PO 4). Then the crude copolyether was refined with adsorbents, and the refined copolyether, which contains less than 0.7 μg/ml K+, was obtained as colorless, viscous liquid.
基金National Natural Science Foundation of China(Grant No.20871008 and 21171011)
文摘In the present study, we investigated the role of reactive oxygen species（ROS） elevation induced by an anti-diabetic vanadium compound, vanadyl acetylacetonate（VO（acac）2）, in the regulation of lipolysis and glucose metabolism using differentiated 3T3L1 adipocytes as a model system. By confocal laser scanning microscopy, we found that VO（acac）2 induced ROS generation under high glucose stimulation, and the pretreatment of NADPH oxidase inhibitors could significantly reduce the elevated ROS level. Meanwhile, the decreased phosphorylated levels of AKT and the two key modulators of lipolysis（HSL and perilipin） were observed by western blot analysis. We also found that the contents of glycerol release were further reduced as well. In addition, the levels of key regulatory proteins, AS160 and GSK3β, in glucose metabolism pathway were correspondingly reduced. These findings demonstrated that ROS induced by vanadium compounds could act as a metabolic signal to activate AKT pathway to inhibit lipolysis and promote glucose transport and glycogen synthesis rather than by direct action by themselves. Our study contributed to elucidate the anti-diabetic effects of vanadium compounds and provided a theoretical basis for the further development of new vanadium complexes in the prevention and therapeutics of diabetes.
