Insight into the active site nature of zeolite H-BEA for liquid phase etherification of isobutylene with ethanol

摘要: The nature of active acid sites zeolite H-BEA with different Si/Al ratios (15–407) in liquid phase etherification isobutylene ethanol a continuous flow reactor the temperature range 80–180 °C has been explored. We describe and discuss data concerning strength concentration obtained by techniques stepwise (quasi-equilibrium) thermal desorption ammonia, X-ray diffraction, low-temperature adsorption nitrogen, FTIR spectroscopy adsorbed pyridine solid-state 27Al MAS NMR. average values energy NH3 on were experimentally determined as 63.7; 91.3 121.9 mmol g−1 (weak, medium, strong, respectively). In agreement this, correlation between rate ethyl-tert-butyl ether synthesis weak (ENH3 = 61.6–68.9 kJ mol−1) observed. It was concluded that for this reaction are Bronsted hydroxyls representing internal silanol groups associated octahedrally coordinated aluminum second coordination sphere.