Nitrogen-Doped Carbon Materials Prepared by Ammoxidation as Solid Base Catalysts for Knoevenagel Condensation and Transesterification Reactions
Nitrogen-Doped Carbon Materials Prepared by Ammoxidation as Solid Base Catalysts for Knoevenagel Condensation and Transesterification Reactions
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DOI：
10.1002/adsc.201000029
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发表时间：
2010-06-01
影响因子：
5.4
通讯作者：
Araib, Masahiko
中科院分区：
文献类型：
--
作者：
Kan-nari, Naokatsu;Okamura, Shuhei;Araib, Masahiko
以工业炭源（炭黑和活性炭）为原料，采用氨氧化法制备了氮掺杂炭材料，并将其应用于Knoevenagel反应和酯交换反应中。结果表明，这些碳材料是活性的，并且活性取决于氨氧化条件（温度和空气中的氨浓度）和所使用的碳源。氮掺杂的碳材料的体积，纹理，和表面性质的几种方法进行了检查，以澄清可能的因素，确定其最终的催化活性。活性炭衍生的催化剂比炭黑衍生的催化剂活性更高。表面积和孔隙率不是造成这两种碳源之间差异的原因，但与氧的反应性差异是重要的。碳源与氧的反应性应影响氮通过与氨和空气的氨氧化作用掺杂到其表面上以及作为碱催化剂的所得活性。催化活性随着氮掺杂量的增加而增加，因此，氮掺杂应该是催化活性的原因。此外，活性在氮氧比约为1时最大，表明氮和氧在碳表面上的协同作用的重要性。
Nitrogen-doped carbon materials were prepared by ammoxidation of commercial carbon sources (carbon black and activated carbon) and applied as base catalysts for Knoevenagel and transesterification reactions. It was shown that these carbon materials were active and the activities were different depending on the ammoxidation conditions (temperature and ammonia concentration in air) and carbon sources used. The bulk, textural, and surface properties of the nitrogen-doped carbon materials were examined by several methods to clarify possible factors determining their final catalytic activities. The activated carbon-derived catalysts were more active than the carbon black-derived ones. The surface area and porosity were not responsible for this difference between the two carbon sources but the difference in the reactivity with oxygen was important. The reactivity of carbon sources with oxygen should influence the doping of nitrogen onto their surfaces by ammoxidation with ammonia and air and the resulting activities as base catalysts. The catalytic activity increases with the amount of nitrogen doped and, therefore, the nitrogen doped should be responsible for the catalytic activities. In addition, the activities are maximal at a ratio of nitrogen to oxygen of around 1, suggesting the importance of cooperative functions of nitrogen and oxygen on the surface of carbons.