Chinese Journal of Catalysis

Chinese Journal of Catalysis ›› 2019, Vol. 40 ›› Issue (4): 567-579.DOI: 10.1016/S1872-2067(19)63302-4

• Article • Previous Articles     Next Articles

Effects of Ni particle size on amination of monoethanolamine over Ni-Re/SiO2 catalysts

Lei Maa,b,d, Li Yana, An-Hui Lub, Yunjie Dinga,c   

  1. a Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China;
    b State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, Liaoning, China;
    c State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China;
    d University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2018-10-24 Revised:2019-01-08 Online:2019-04-18 Published:2019-03-14
  • Supported by:

    This work was supported by the National Natural Science Foundation of China (21273227) and Strategic Priority Research Program of Chinese Academy of Sciences (XDB17000000).

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Abstract:

Ni-Re/SiO2 catalysts with controllable Ni particle sizes (4.5-18.0 nm) were synthesized to investigate the effects of the particle size on the amination of monoethanolamine (MEA). The catalysts were characterized by various techniques and evaluated for the amination reaction in a trickle bed reactor at 170℃, 8.0 MPa, and 0.5 h-1 liquid hourly space velocity of MEA (LHSVMEA) in NH3/H2 atmosphere. The Ni-Re/SiO2 catalyst with the lowest Ni particle size (4.5 nm) exhibited the highest yield (66.4%) of the desired amines (ethylenediamine (EDA) and piperazine (PIP)). The results of the analysis show that the turnover frequency of MEA increased slightly (from 193 to 253 h-1) as the Ni particle sizes of the Ni-Re/SiO2 catalysts increased from 4.5 to 18.0 nm. Moreover, the product distribution could be adjusted by varying the Ni particle size. The ratio of primary to secondary amines increased from 1.0 to 2.0 upon increasing the Ni particle size from 4.5 to 18.0 nm. Further analyses reveal that the Ni particle size influenced the electronic properties of surface Ni, which in turn affected the adsorption of MEA and the reaction pathway of MEA amination. Compared to those of small Ni particles, large particles possessed a higher proportion of high-coordinated terrace Ni sites and a higher surface electron density, which favored the amination of MEA and NH3 to form EDA.

Key words: Particle size effects, Monoethanolamine, Amination reaction, Ni-Re/SiO2, Turn over frequency