Preparation of Cu-ZSM-5 Zeolite Without Organic Template for the Selectively Catalytic Oxidation of Styrene
Tetracoordinated copper modified ZSM-5 zeolite(Cu-ZSM-5)was prepared without any organic template by acid hydrolysis,alkaline aging,and hydrothermal crystallization of copper(Ⅱ)nitrate and tetraethyl orthosilicate(TEOS).The effect of Si/Al molar ratio of gel,pH value,crystallization temperature and crystallization time on the crystal form and the relative crystallinity of Cu-ZSM-5 was investigated.Meantime,ZSM-5 was analyzed and characterized using X-ray diffraction(XRD),Fourier transform infrared(FT-IR)spectra,UV diffuse reflectance spectrum and X-ray photoelectron spectroscopy.The results show that Cu-ZSM-5 zeolite is characterized with MFI structure,high crystallinity and no other impurities.Copper atoms are mainly tetracoordinated.Tetracoordinated copper is an active site for catalytic oxidation of styrene.When meeting the following conditions:m(Cu-ZSM-5-50)=0.1 g,n(TBHP)/n(Styrene)=1.5,T=60 ℃,t=5 h,styrene conversion and Benzaldehyde selectivity are 76.5 and 69.4％,respectively,indicating that Cu-ZSM-5-50 has high catalytic activity and good reusability.This preparation method does not need organic templates or high-temperature roasting,thus greatly reducing the preparation cost of Cu-ZSM-5.
NETL
NSTL
万方数据
