排序方式: 共有49条查询结果,搜索用时 906 毫秒
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乙醇在新型Mo/C催化剂上的气相羰基化反应 总被引:1,自引:0,他引:1
The carbonylation of alcohol to acid or ester is an important process in the chemical industry. The Monsanto process for acetic acid via the homoge neous carbonylation of methanol is an example of the largest scale commercial application of this route[1].Recently, ethanol carbonylation for manufacturing propionic acid and ethyl propionate became an at tractive approach, and many research efforts were made for an appropriate catalyst to carry out the va por phase carbonylation under atmospheric pres sure[2~4]. Although an iodide-promoted Ni/C cata lyst is found to exhibit satisfactory activity and se lectivity for the vapor phase carbonylation of ethanol, it is affected by the disadvantages associat ed with a highly corrosive reaction medium and dif ficult product separation owing to the use of ethyl iodide as promoter. There has been little success in finding heterogeneous or homogeneous catalyst that can operate effectively without a halide promoter[5]. 相似文献
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The nanocarbonaceous material with helical structure is considered to be promising as nanocoils. Both left and right-handed helical structures normally coexist and are disordered. So far, there has been no report about double or multi-directional helical structures on an individual nanomaterial. In this paper, Multi-directional helical structures were observed in an individual carbon nanofiber during the pyrolysis of acetylene at a mixture of C2H2∶H2=2∶1. It is possible to control and prepare multi-directional helical nanomaterial, and it can be used into new application area. 相似文献
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钼催化剂上甲醇直接气相羰基化活性与吸附的关系 总被引:1,自引:0,他引:1
制备了一系列非负载的钼催化剂,考察了催化剂上甲醇直接气相\r\n羰化活性与反应物及产物吸附的关系.结果发现,催化剂的制备方法对\r\n甲醇直接气相羰化活性的影响很明显,以纯二硫化钼试剂制备的催化剂\r\n,甲醇转化率与羰化产物乙酸甲酯的选择性最低;以三氧化钼气相还原\r\n硫化制备的催化剂,其羰化活性较低;以钼酸铵溶液经硫化铵溶液或硫\r\n化氢气体硫化制得的催化剂,其性能明显优于前两种,尤以钼酸铵经硫\r\n化铵溶液硫化制得的催化剂的性能最佳.催化剂的羰化活性明显依赖于\r\n催化剂的吸附性能,羰化活性高的催化剂不仅吸附CO的量大,而且对甲\r\n醇和乙酸甲酯的吸附量也明显较大. 相似文献
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近年来,碳纳米管(CNTs)[1]作为新型催化剂载体方面的研究[2~11]受到了广泛关注。由于碳纳米管具有纳米级卷曲的表面,与石墨烯相比其表面π键发生变化,从而导致新的电子结构[12],因此碳纳米管负载的催化剂在涉及电子传输过程的催化过程中具有特别的吸引力。燃料电池电极催化剂就是其中典型的一类[13~15]。已有研究者选用碳纳米管作为载体,将Pt[16~19]、PtRu[20,21]等具有催化活性的贵金属或其合金负载到碳纳米管上,展现出了很好的电催化氧化活性。然而,到目前为止,制备用于燃料电池的具有均匀尺寸和分散性的负载型纳米催化剂仍然是一项… 相似文献
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微乳法合成纳米SiO2/TiO2及其光催化性能 总被引:1,自引:0,他引:1
采用聚乙二醇辛基苯基醚(Triton X-100)/正己醇/环己烷/氨水微乳体系合成了纳米TiO2和SiO2/TiO2复合物,用X射线衍射、红外光谱和透射电镜对其结构进行了表征,并以甲基橙降解评价了其光催化性能,讨论了SiO2/TiO2摩尔比、晶相组成及粒径与光催化活性的关系.结果表明,SiO2/TiO2催化剂中形成了新的Ti-O-Si键和无定形SiO2;在纳米TiO2中复合SiO2能有效抑制锐钛矿向金红石的转变,增加锐钛矿的稳定性,并阻止TiO2晶粒的聚集生长.催化剂的光催化活性随金红石含量的增加而降低,加入适量SiO2能明显提高TiO2的光催化活性,其中摩尔比为1/7的SiO2/TiO2光催化活性最高. 相似文献
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甲醇直接气相羰基化Mo/C催化剂 总被引:12,自引:3,他引:9
为了“优化燃料资源,创建能源化工体系”,开展甲醇下游产品的研究是当今燃料化工的重要内容之一。70年代初美国Monsanto开发的Rh-Ⅰ催化体系使甲醇液相羰基化制醋酸大规模工业化,由于该体系采用昂贵紧缺的金属铑,催化剂需精心回收;并且由于需要大量碘化... 相似文献
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甲醇直接气相羰基化Mo/C催化剂表征 总被引:2,自引:1,他引:1
甲醇在无任何促进剂作用下,直接与一氧化碳气相羰基化合成醋酸甲酯是对传统的甲醇必须在碘化物作用下液相羰基化的挑战[1]。作者已报道了负载的硫化物钴钼和硝酸镍两类催化剂用于甲醇的直接气相羰基化具有较好的活性[2,3],最近又发现硫化后再还原的MoC催化剂比硫化的C... 相似文献