This paper presents the NUBASE2012 evaluation that contains the recommended values for nuclear and decay properties of nuclides in their ground and excited isomeric （T1/2≥ 100 ns） states. All nuclides for which som...This paper presents the NUBASE2012 evaluation that contains the recommended values for nuclear and decay properties of nuclides in their ground and excited isomeric （T1/2≥ 100 ns） states. All nuclides for which some experimental information is known are considered. NUBASE2012 covers all up to date experimental data published in primary （journal articles） and secondary （mainly laboratory reports and conference proceedings） references, together with the corresponding bibliographical information. During the development of NUBASE2012, the data available in the ＂Evaluated Nuclear Structure Data File＂ （ENSDF） database were consulted, and critically assessed of their validity and completeness. Furthermore, a large amount of new and somewhat older experimental results that were missing in ENSDF were compiled, evaluated and included in NUI3ASE2012. The atomic mass values were taken from the ＂Atomic Mass Evaluation＂ （AME2012, second and third parts of the present issue）. In cases where no experimental data were available for a particular nuclide, trends in the behavior of specific properties in neighboring nuclei （TNN） were examined. This approach allowed to estimate, whenever possible, values for a range of properties, and are labeled in NUBASE2012 as ＂non-experimental＂ （flagged ＂#＂）. Evaluation procedures and policies that were used during the development of this database are presented, together with a detailed table of recommended values and their uncertainties.展开更多
2,5-Furandicarboxylic(FDCA) is a potential substitute for petroleum-derived terephthalic acid, and aerobic oxidation of5-hydroxymethylfurfural(HMF) provides an efficient route to synthesis of FDCA. On an activated car...2,5-Furandicarboxylic(FDCA) is a potential substitute for petroleum-derived terephthalic acid, and aerobic oxidation of5-hydroxymethylfurfural(HMF) provides an efficient route to synthesis of FDCA. On an activated carbon supported ruthenium(Ru/C) catalyst(with 5 wt% Ru loading), HMF was readily oxidized to FDCA in a high yield of 97.3% at 383 K and 1.0 MPa O_2 in the presence of Mg(OH)_2 as base additive. Ru/C was superior to Pt/C and Pd/C and also other supported Ru catalysts with similar sizes of metal nanoparticles(1–2 nm). The Ru/C catalysts were stable and recyclable, and their efficiency in the formation of FDCA increased with Ru loadings examined in the range of 0.5 wt%–5.0 wt%. Based on the kinetic studies including the effects of reaction time, reaction temperature, O_2 pressure, on the oxidation of HMF to FDCA on Ru/C, it was confirmed that the oxidation of HMF to FDCA proceeds involving the primary oxidation of HMF to 2,5-diformylfuran(DFF) intermediate, and its sequential oxidation to 5-formyl-2-furancarboxylic acid(FFCA) and ultimately to FDCA, in which the oxidation of FFCA to FDCA is the rate-determining step and dictates the overall formation rate of FDCA. This study provides directions towards efficient synthesis of FDCA from HMF, for example, by designing novel catalysts more efficient for the involved oxidation step of FFCA to FDCA.展开更多
文摘This paper presents the NUBASE2012 evaluation that contains the recommended values for nuclear and decay properties of nuclides in their ground and excited isomeric （T1/2≥ 100 ns） states. All nuclides for which some experimental information is known are considered. NUBASE2012 covers all up to date experimental data published in primary （journal articles） and secondary （mainly laboratory reports and conference proceedings） references, together with the corresponding bibliographical information. During the development of NUBASE2012, the data available in the ＂Evaluated Nuclear Structure Data File＂ （ENSDF） database were consulted, and critically assessed of their validity and completeness. Furthermore, a large amount of new and somewhat older experimental results that were missing in ENSDF were compiled, evaluated and included in NUI3ASE2012. The atomic mass values were taken from the ＂Atomic Mass Evaluation＂ （AME2012, second and third parts of the present issue）. In cases where no experimental data were available for a particular nuclide, trends in the behavior of specific properties in neighboring nuclei （TNN） were examined. This approach allowed to estimate, whenever possible, values for a range of properties, and are labeled in NUBASE2012 as ＂non-experimental＂ （flagged ＂#＂）. Evaluation procedures and policies that were used during the development of this database are presented, together with a detailed table of recommended values and their uncertainties.
基金supported by the National Natural Science Foundation of China(21373019,21433001,21690081)
文摘2,5-Furandicarboxylic(FDCA) is a potential substitute for petroleum-derived terephthalic acid, and aerobic oxidation of5-hydroxymethylfurfural(HMF) provides an efficient route to synthesis of FDCA. On an activated carbon supported ruthenium(Ru/C) catalyst(with 5 wt% Ru loading), HMF was readily oxidized to FDCA in a high yield of 97.3% at 383 K and 1.0 MPa O_2 in the presence of Mg(OH)_2 as base additive. Ru/C was superior to Pt/C and Pd/C and also other supported Ru catalysts with similar sizes of metal nanoparticles(1–2 nm). The Ru/C catalysts were stable and recyclable, and their efficiency in the formation of FDCA increased with Ru loadings examined in the range of 0.5 wt%–5.0 wt%. Based on the kinetic studies including the effects of reaction time, reaction temperature, O_2 pressure, on the oxidation of HMF to FDCA on Ru/C, it was confirmed that the oxidation of HMF to FDCA proceeds involving the primary oxidation of HMF to 2,5-diformylfuran(DFF) intermediate, and its sequential oxidation to 5-formyl-2-furancarboxylic acid(FFCA) and ultimately to FDCA, in which the oxidation of FFCA to FDCA is the rate-determining step and dictates the overall formation rate of FDCA. This study provides directions towards efficient synthesis of FDCA from HMF, for example, by designing novel catalysts more efficient for the involved oxidation step of FFCA to FDCA.
