Ferrierite(FER) zeolites were synthesized by solid transformation at different alkalinities(OH-/Al2O3 molar ratios). The in situ delamination of FER zeolites were achieved and their catalytic performances in the catal...Ferrierite(FER) zeolites were synthesized by solid transformation at different alkalinities(OH-/Al2O3 molar ratios). The in situ delamination of FER zeolites were achieved and their catalytic performances in the catalytic cracking of C4 hydrocarbons were examined. The relationships among the OH-/Al2O3 molar ratio, FER structure,composition, surface acidity and catalytic performance in C4 hydrocarbon cracking were investigated. The results of X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, inductively coupled plasma atomic emission spectroscopy, N2 adsorption, NH3temperature-programmed desorption and catalytic cracking showed that with increasing OH-/Al2O3 molar ratio in the synthesis gel, the Si O2/Al2O3 molar ratio of the as-synthesized FER zeolite decreased, the amount of acid sites in the corresponding H-FER increased, and the acid strength weakened. Additionally, the FER zeolite was delaminated at the mesoscale. H-FER5 synthesized at the highest alkalinity had the largest number of acid sites and exhibited the highest catalytic activity in C4 hydrocarbon catalytic cracking among three of the prepared catalysts. H-FER3 synthesized at the secondhighest alkalinity showed that the highest yield of benzene and toluene because of the secondary pores resulted from the gaps between the layers, which were beneficial to the diffusion and formation of large molecules.展开更多
基金Supported by the NSFC of China(20973123)the National Basic Research Program of China(2012CB215002)+1 种基金the International Science and Technology Cooperative Program of China(2010DFB40440)Shanxi Basic Research Projects(2012011005-7,2012011008-3)
文摘Ferrierite(FER) zeolites were synthesized by solid transformation at different alkalinities(OH-/Al2O3 molar ratios). The in situ delamination of FER zeolites were achieved and their catalytic performances in the catalytic cracking of C4 hydrocarbons were examined. The relationships among the OH-/Al2O3 molar ratio, FER structure,composition, surface acidity and catalytic performance in C4 hydrocarbon cracking were investigated. The results of X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, inductively coupled plasma atomic emission spectroscopy, N2 adsorption, NH3temperature-programmed desorption and catalytic cracking showed that with increasing OH-/Al2O3 molar ratio in the synthesis gel, the Si O2/Al2O3 molar ratio of the as-synthesized FER zeolite decreased, the amount of acid sites in the corresponding H-FER increased, and the acid strength weakened. Additionally, the FER zeolite was delaminated at the mesoscale. H-FER5 synthesized at the highest alkalinity had the largest number of acid sites and exhibited the highest catalytic activity in C4 hydrocarbon catalytic cracking among three of the prepared catalysts. H-FER3 synthesized at the secondhighest alkalinity showed that the highest yield of benzene and toluene because of the secondary pores resulted from the gaps between the layers, which were beneficial to the diffusion and formation of large molecules.
