In Situ Delamination of Ferrierite Zeolite and its Performance in the Catalytic Cracking of C4 Hydrocarbons

Abstract

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, NH3 temperature-programmed desorption and catalytic cracking showed that with increasing OH−/Al2O3 molar ratio in the synthesis gel, the SiO2/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 second-highest 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.