Catalytic hydroisomerization properties of nanosized ZSM-23 zeolite for n-dodecane

Bingchun Wang
Dalian Institute of Chemical Physics,Chinese Academy of Sciences

Zhusheng Xu
Dalian Institute of Chemical Physics,Chinese Academy of Sciences

Wei Qu
Dalian Institute of Chemical Physics,Chinese Academy of Sciences

Zhijian Tian
Dalian Institute of Chemical Physics,Chinese Academy of Sciences

Yunpeng Xu
Dalian Institute of Chemical Physics,Chinese Academy of Sciences

Liwu Lin
Dalian Institute of Chemical Physics,Chinese Academy of Sciences

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Abstract
Catalytic hydroisomerization properties of nanosized ZSM-23 zeolite for n-dodecane

Bingchun Wang*1, Zhusheng Xu1, Wei Qu 1, Zhijian Tian1*, Yunpeng Xu 1, Liwu Lin2

1 Natural Gas Utilization and Applied Catalysis Laboratory, Dalian Institute of Chemical Physics,Chinese Academy of Sciences, P.O. Box 110, Dalian 116023, P. R. China.
2State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics,Chinese Academy of Sciences, P.O. Box 110, Dalian 116023, P. R. China.
* e-mail: wangbc@dicp.ac.cn, tianz@dicp.ac.cn

In recent years, due to the implementation of more and more stringent environmental legislations, the production of high quality and clean diesel and lubricating oil has received significant attentions. Hydroisomerization of long-chain n-alkane has attracted much interest for its application in the field of isodewaxing of hydrocarbon feedstock [1]. ZSM-23 zeolite, possessing the 10-ring nonintersecting elliptic channels of 0.56 nm×0.45 nm [2], exhibits preferential selectivity for skeletal isomerization of paraffins. However, it often shows fast deactivation , mainly due to poor diffusion efficiency in the 1-D channels. So much more effects have been made to the preparation of nanosized zeolites utilizing different methods [3] for the purpose of reduce the diffusional limitation.
In the present work, nanosized ZSM-23 zeolites were synthesized successfully under hydrothermal conditions using pyrrolidine as template, and also characterized by XRD, Nitrogen adsorption/desorption analyses and NH3-TPD et al. Catalytic properties in the hydroisomerization reaction of dodecane of these samples were also investigated.
BET result indicates that the ratio of external surface area of nanosized ZSM-23 is higher than that of normal sized zeolite.The data of the isomerization of n-dodecane indicate that the catalytic activity of 0.5wt% platium loaded on nanosized ZSM-23 is higher than that of normal sized zeolite. However, the selectivity for the mono-methyl and bi-methyl isomers of the former is similar with that of the latter.


References
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