Recently, the research group led by Prof. Liu Zhongmin from Dalian Institute of Chemical Physics of the Chinese Academy of Sciences elucidated the role of ball milling during Cs/X catalyst preparation and effects on catalytic performance in side-chain alkylation of toluene with methanol.
Styrene is an important chemical intermediate, the downstream products from which are very rich. The route for production of styrene by side chain alkylation of toluene with methanol on alkaline materials has great potential in industrial application.However, commercial application is not yet implemented due to the lack of efficient catalysts. Compared with other catalysts, the modified cesium ion exchanged X zeolites (CsX) perform best so far.
The group adopted a physical modification method, ball milling method, to modify CsX zeolites. Ball-milling modification was performed over Cs/X catalyst before or after Cesium ion exchange and the effect of which on the reaction was compared. It was found that the catalytic performance of CsX zeolites is greatly improved after ball milling. The modification mechanism of ball milling on CsX zeolites has been further explained: the particles of Cs2O on zeolites interact with zeolites again during the process of ball milling which generates some new basic sites such as Si-O-Cs and Al-O-Cs. These new basic centers are different from those on traditional CsX zeolites and may help to promote side-chain methylation reaction. However, ball milling for long time will lead to the complete collapse of catalyst structure and disappearance of micropores and consequently the decreased catalytic activity, which also suggests the importance of micropores to the side chain alkylation. The advantage of ball milling methods lies that the catalytic performance can be improved by adjustingthe acid-base properties of CsX catalysts without increasing Cs content.
This work was published in the Chinese Journal of Catalysis.（Text/Graph by Yu Qijun）
Role of ball milling during Cs/X catalyst preparation and effects on catalytic performance in side-chain alkylation of toluene with methanol. QijunYu, Jinzhe Li, Changcheng Wei, Shu Zeng, Shutao Xu, Zhongmin Liu*, Chinese Journal of Catalysis, 41(8):1268-1278, 2020.
