Abstract：Nano-Beta zeolite was synthesized and characterized by various techniques, such as X-ray diffraction(XRD), transmission electron microscope(TEM), low-temperature isotherm of nitrogen adsorption and desorption(BET), NH3 temperature-programmed desorption(NH3-TPD) and pyridine infrared spectroscopy(Py-IR). The catalytic performance of nano-Beta were also investigated in comparing with that of conventional Beta with large crystal size and the key parameters of alkylation were optimized in order to reach best performance in industrial cumene process. The results showed that the nano-Beta with molar ratio of SiO2 to Al2O3 25-30 had higher crystallinity and very small crystal size about 20 nm. Compared to conventional Beta with large crystal size, the nano-Beta had much larger BET surface area of 600 m2/g and higher pore volume of 0.42 cm3/g, which mainly came from mesopore and macropore, and possessed higher concentration of total acid sites and Bronsted acid sites. As catalyst for alkylation of benzene with propylene, nano-Beta zeolite was more stable and more selective. Under the conditions of benzene to propylene molar ratio of 3.0 and reaction temperature of 150-160 ℃, nano-Beta zeolite exhibited the best catalytic performance. Cumene selectivity reached as high as 89% and impurity, especially, n-propylbenzene decreased to very low level. During long term industrial test, nano-Beta catalyst also had much longer life span and higher selectivity than conventional Beta.
Zong Hongyuan,Gao Huanxin,Wei Yilun. Synthesis and Characterization of Nano Beta Zeolite and ItsCatalytic Performance for Alkylation of Benzene with Propylene[J]. Chemical Reaction Engineering and Technology, 2015, 31(2): 142-149.
