Cooperation of hierarchical pores with strong Brønsted acid sites on SAPO-34 catalysts for the glycerol dehydration to acrolein

Abstract

The hierarchical SAPO-34 zeolites have been prepared with the simultaneous generation of strong Brønsted acid sites (BASs) via a post-synthetic method, which allows the cooperation of the positive effects of both porous structure and acidity in the dehydration of glycerol to acrolein. The cooperation of strong BASs only in enhancing the acrolein selectivity and the hierarchical pores in improving the glycerol conversion has significantly increased the overall acrolein yield to 89.8% on the hierarchical SAPO-34 zeolite at 345 °C and WHSV = 3.7 h -1 . This kind of cooperation also limited the catalyst deactivation and prolonged the lifetime of zeolites, which is another significant challenge for glycerol dehydration. The knowledge from this research is very valuable to design the high-efficient nanoporous catalysts for hydrocarbon conversion and bio-refining.

Synergy of Extraframework Al3+ Cations and Brønsted Acid Sites on Hierarchical ZSM-5 Zeolites for Butanol-to-Olefin Conversion

“…The identified peak is a typical peak for Al IV species (bridging Si−OH−Al groups) in zeolites. 20,29,35,39 Contributing from the humidity penetration during the MAS measurement, the line broadening is less severe (from 30 to 65 ppm) compared to the previously reported research. 32 After the rehydration process (Figure 2b), no observable change can be identified in the 27 Al NMR spectrum except the line narrowing of the Al IV peak, indicating no extraframework Al species existing on zeolites.…”

“…The h-ZSM-5 (50) and Al/h-ZSM-5 (50) zeolites have a hysteresis loop that can provide evidence for additional mesoporous structure. 20,35,36 The pore size distributions of h-ZSM-5 (50) and Al/h-ZSM-5 (50) zeolites have been further analyzed by using BJH methods. As presented in Figure S2b, both the h-ZSM-5 (50) and Al/h-ZSM-5 (50) zeolites have an average mesopore size of around 4−6 nm.…”

“…N 2 adsorption−desorption isotherms measurements were performed at 77 K on an Autosorb IQ-C system after outgassing the sample under vacuum at 573 K for 10 h. The specific surface area was calculated with the Brunauer−Emmett−Teller (BET) equation. 35,36 The 27 Al and 31 P MAS NMR spectra were recorded by using a Bruker Avance III 400WB spectrometer at room temperature operated at a B 0 field of 9.4 T with Larmor frequencies of 104.3 and 161.9 MHz, respectively. A sample spinning rate of 12 kHz with 4 mm rotors was used for all experiments.…”

Treatment of zeolite adsorbed material as a potential nuclear waste glass‐ceramic matrix

“…The special chemical structure of zeolite forms many holes and channels, which makes it to have a larger specific surface area and more adsorption sites. Therefore, zeolite has a strong adsorption property 15 . The isothermal characteristics of zeolite adsorption, 16,17 adsorption kinetics, 18 and adsorption thermodynamics were analyzed.…”

“…Therefore, zeolite has a strong adsorption property. 15 The isothermal characteristics of zeolite adsorption, 16,17 adsorption kinetics, 18 and adsorption thermodynamics were analyzed. It can be found that zeolite can be considered for the adsorption of radioactive wastes due to the good adsorption property of zeolite.…”