催化学报 ›› 2014, Vol. 35 ›› Issue (3): 437-443.DOI: 10.1016/S1872-2067(14)60008-5

• 研究论文 • 上一篇    下一篇

La(OH)3和La2O2CO3纳米棒的合成及其催化Claisen-Schmidt缩合反应性能

王非, 塔娜, 李勇, 申文杰   

  1. 中国科学院大连化学物理研究所催化基础国家重点实验室, 辽宁大连116023
  • 收稿日期:2013-11-09 修回日期:2013-12-23 出版日期:2014-02-26 发布日期:2014-02-26
  • 通讯作者: 申文杰
  • 基金资助:

    国家自然科学基金(20923001,21025312);国家重点基础研究发展计划(973计划,2013CB933100).

La(OH)3 and La2O2CO3 nanorod catalysts for Claisen-Schmidt condensation

Fei Wang, Na Ta, Yong Li, Wenjie Shen   

  1. State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
  • Received:2013-11-09 Revised:2013-12-23 Online:2014-02-26 Published:2014-02-26
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (20923001, 21025312) and the National Basic Research Program of China (973 Program, 2013CB933100).

摘要:

通过调节溶液的pH值,在水热条件下合成出长径比为2-45的La(OH)3纳米棒. 对水热合成过程中间体的结构演变分析,发现高碱度有利于小尺寸晶核的形成,La(OH)3晶体结构的各向异性导致这些晶种沿着C轴方向生长,进而形成纳米棒结构. 将La(OH)3纳米棒前驱体于773 K焙烧可以得到长径比为2-20的La2O2CO3纳米棒. 随着长径比的增加,La2O2CO3纳米棒暴露的(110)晶面逐渐增加,La3+-O2-碱性位的数目也从0.08增加到0.24 mmol/g. 因此,在Claisen-Schmidt缩合反应中,La2O2CO3纳米棒催化剂上的反应速率随着长径比的增加而逐渐增大.

关键词: 氢氧化镧, 碳酸氧镧, 纳米棒, 晶面, 碱性, Claisen-Schmidt缩合反应

Abstract:

La(OH)3 nanorods of 15 nm diameter and up to 700 nm long were synthesized using different pH values of the solution used in the hydrothermal synthesis. A more alkaline solution favored the formation of tiny La(OH)3 nuclei, which grew along the c-axis due to their anisotropic nature and led to the formation of rod-shaped crystals. Calcination of the La(OH)3 nanorods at 773 K gave La2O2CO3 nanorods. Their basic properties were correlated with their size. As the aspect ratio increased from 2 to 20, the basic sites increased from 0.08 to 0.24 mmol/g, which was due to a higher exposure of (110) planes. In the catalysis of the condensation reaction of benzaldehyde with acetophenone, the reaction rate was correlated with the number of La3+-O2- pairs on the exposed (110) facets of the La2O2CO3 nanorods.

Key words: La(OH)3, La2O2CO3, Nanorod, Crystal facet, Basicity, Claisen-Schmidt condensation