Dealumination of Nanosized Zeolites Y

HPW supported on ammonium hexafluorosilicate modified Hβ: Efficient catalysts for ethylene glycol and methyl tert‐butyl ether reaction with high selectivity and stability

“…Therefore, the possible reasons for the variation in acidic site density of the 30HPW/Hβ‐Si(x) catalysts are as follows (shown in Scheme 1): The strong acid density decreased due to the extraframework aluminum of 30HPW/Hβ‐Si(x) was removed, and internal Si‐OH groups are filled with silicon of ammonium fluorosilicate. The strong, medium, and weak acid density decreased due to the SiO 2 (the hydrolysis product of excess AHFs) formed on the 30HPW/Hβ‐Si(x) catalysts after the 30HPW/Hβ catalysts were treated with AHFs solution 45,61 . These results are in line with corresponding XRD, FT‐IR, and N 2 adsorption–desorption characterization results.…”

“…The strong, medium, and weak acid density decreased due to the SiO 2 (the hydrolysis product of excess AHFs) formed on the 30HPW/Hβ-Si(x) catalysts after the 30HPW/Hβ catalysts were treated with AHFs solution. 45,61 These results are in line with corresponding XRD, FT-IR, and N 2 adsorption-desorption characterization results. Figure 6 shows the Py-IR spectra of Hβ, Hβ-Si(0.1), and 30HPW/Hβ-Si(0.1), and Table 2 lists the Brønsted/ Lewis ratio of the Hβ, Hβ-Si(0.1) and 30HPW/Hβ-Si(0.1).…”

“…The internal Si‐OH groups of Hβ (strong acidity sites) were filled with silicon of AHFs. The SSA and the total pore volume of 30HPW/Hβ‐Si(x) decreased as concentration of AHFs further increased from 0.2 to 0.4 mol·L −1 , which is due to SiO 2 (the hydrolysis product of excess AHFs) on the 30HPW/Hβ‐Si(x) catalysts after the 30HPW/Hβ catalysts were treated with a high concentration of AHFs solution (0.2 to 0.4 mol·L −1 ) 45 …”

“…The SSA and the total pore volume of 30HPW/ Hβ-Si(x) decreased as concentration of AHFs further increased from 0.2 to 0.4 molÁL À1 , which is due to SiO 2 (the hydrolysis product of excess AHFs) on the 30HPW/ Hβ-Si(x) catalysts after the 30HPW/Hβ catalysts were treated with a high concentration of AHFs solution (0.2 to 0.4 molÁL À1 ). 45 The XRD patterns of the 30HPW/Hβ-Si(x), 30HPW/ Hβ, Hβ-Si(0.1), and Hβ were shown in Figure 2, and Table 1 listed the structural properties of these catalysts. No HPW characteristic peaks were detected in the XRD patterns of 30HPW/Hβ and 30HPW/Hβ-Si(x), indicating HPW was highly dispersed on Hβ support as small nanoclusters of a few Keggin units.…”