Performance of Alkaline-Treated ZSM-5 for Ethanol to Propylene
1. College of Life Science, Dalian Nationalities University, Dalian 116600, China;
2. School of Chemical Engineering, Dalian University of Technology, Dalian 116024, China
Abstract In order to improve the catalytic performance of zeolites that convert ethanol to propylene, ZSM-5 zeolites were modified using NaOH solution(0.2 mol/L), and the modified ZSM-5 zeolites were characterized by X-ray diffraction(XRD), scanning electron microscope(SEM), N2 sorption-desorption and temperature programmed desorption(NH3-TPD) techniques. The influence of NaOH-treatment on the structure, morphology and acidity was investigated. It was found that after the 120 min NaOH-treatment on ZSM-5, a certain amount of mesopores were produced and the surface acidity was slightly weakened. However, the NaOH-treated ZSM-5 still kept the MFI microporous skeleton structure. The modified ZSM-5 zeolites were used to transform ethanol to propylene. Compared to ZSM-5, the NaOH-treated ZSM-5 showed significant increase in the propylene yield. A propylene yield as high as 28.8% was obtained at 500 ℃. The improvement of catalytic performance could be attributed to the modification of surface acidity of ZSM-5 and the formation of mesopores.
