Study on Transalkylation of Benzene with Diethyl /Triethyl-Benzen over Modified Y Zeolite
1. State Key Laboratory of Green Chemical Engineering and Industrial Catalysis, Shanghai Research Institute of Petrochemical Technology, SINOPEC, Shanghai 201208, China;
2. School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China;
3. Key Laboratory for Advanced Materials and Research Institute of Industrial Catalysis, East China University of Science and Technology, Shanghai 200237, China;
Abstract：In order to improve the performance of the transalkylation catalyst, a series of ultra stable Y (USY) molecular sieves were obtained by the modification process of NaY zeolite with different molar ratios of framework SiO2/Al2O3 (5.0, 5.5, and 5.9) and “the combination of NH4+ ion exchange and hydrothermal-thermal treatments”. The framework of each USY molecular sieve was characterized by X-ray diffraction (XRD), N2-physical adsorption, scanning electron microscopy (SEM), temperature programmed desorption (NH3-TPD), pyridine adsorption infrared spectroscopy (Py-IR), and the catalytic performance on the USY molecular sieves was evaluated during diethyl/triethylbenzene-benzene transalkylation. The results showed that the hydrothermal modification of NaY zeolite with SiO2/Al2O3 ratio of 5.9 was beneficial to maintain the microporous structure and the prepared USY molecular sieve had a large specific surface area and mesopore volume and a high ratio of strong Brønsted acid sites (Brønsted/Lewis ratio of 1.01), which enhanced the accessibility of the active sites and the diffusion capacity. In addition, strong acid sites can also provide sufficient active sites for benzene and poly ethylbenzene transalkylation reactions. Under the experimental conditions of reaction temperature 170 ℃, reaction pressure 3 MPa, mass ratio of benzene to polyethylbenzene 2 and mass space velocity of 3.3 h-1, the conversion of diethylbenzene and triethylbenzene reached over 67% and 55%, ethylbenzene selectivity reached 99%. Therefore, further adjustment of the synthetic process of NaY zeolite to synthesize higher ratio Si/Al Y zeolite can improve the activity of the transalkylation catalysts.
Guo Dongdong1,3,Yang Weimin1 et al. Study on Transalkylation of Benzene with Diethyl /Triethyl-Benzen over Modified Y Zeolite[J]. 化学反应工程与工艺, 2016, 32(5): 423-431.
