Synthesis and structure of the medium-pore zeolite PST-35 with two interconnected cages of unusual orthorhombic shape

Abstract

The search for new zeolite structures and compositions remains important in synthetic materials science due to the high impact on developing new chemical technologies, as well as on improving existing...

Unveiling the Structural Characteristics of Intergrowth Zeolites Synthesized in the Presence of Isopropylimidazolium-Based Cations and Fluoride Anions

“…Powder X-ray diffraction (PXRD), elemental and thermal analyses, scanning electron microscopy (SEM), 1 H– 13 C cross-polarization (CP), 19 F, 27 Al, and 29 Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) measurements, and OSDA stabilization energy calculations were performed, as described in our previous papers. − High-resolution synchrotron PXRD data were collected on the 9B beamline of the Pohang Acceleration Laboratory (PAL; Pohang, Korea). Le Bail refinement of the PXRD data obtained was done within the program EXPO2004 .…”

“…In fact, we were able to discover four novel zeolite structures under excess fluoride conditions: three aluminosilicates with Si/Al ratios of ca. 10 (PST-21 (framework type PWO ; HF/OSDA = 2.0), PST-22 ( PWW ; HF/OSDA = 2.0), and PST-30 ( PTY ; HF/OSDA = 4.0)) and one germanosilicate with Si/Ge = 2.2–6.1 (PST-35 ( PTF ; HF/OSDA = 2.0)). − PST-24, a transnormal disordered zeolite with varying intracrystalline channel dimensionality, is another product of this approach . In addition, we have shown that the Al distribution over the two crystallographically distinct T-sites in the levyne ( LEV ) framework differs according to the F – concentration in the synthesis mixtures …”

“…In an all-silica composition, this OSDA also yielded SSZ-31, a highly complex intergrowth of at least four different large-pore polymorphs, 20,21 at OSDA/Si = 0.50 and HF/ OSDA = 3.0 or OSDA/Si = 0.75 and HF/OSDA = 2.0 and SSZ-35 (STF), 22 a 1D medium-pore zeolite, at OSDA/Si = 1.00 and HF/OSDA = 1.0 (Figure S1). SSZ-31 was first synthesized as a borosilicate composition using various sophisticated OSDAs like N,N,N-trimethyltricyclo[5.2.1.0 2,6 ]decaneammonium and preferably Na + in hydroxide media and subsequently as an all-silica one using N,N-dimethyl-6azonium-1,3,3-trimethylbicyclo(3.2.1)octane or N,N-diethyl-6-azonium-1,3,3-trimethylbicyclo(3.2.1)octane in fluoride media. 23,24 Prior to this work, the synthesis of RTH/ITE and SSZ-31 intergrowths, as well as STF, using iP13DEI, a simpler OSDA, has not been reported.…”

Double Four Ring Units‐Containing Zeolites: Synthesis, Structural Modification and Catalytic Applications

“…[15g,26] Hong and coworkers reported the synthesis of PST-35 with a 1D medium-pore system by increasing the F À content and using the long-known 1,2,3-triethylimidazolium cation as an OSDA. [26] They found a pure PST-35 phase can be obtained when the HF À /OH À ratio reached 2.0. Wu and coworkers regulated the gel compositions and nucleation processes by using a low content of F À (F À / OH À = 0.2), resulting in the synthesis of ECNU-13P.…”

“…Besides, 2D channel systems were found in these NSL-type germanosilicate zeolites. Even though, we also can find many differences in the size of the [20] 2004 [21] *CTH CIT-13 NUD-2 SAZ-1 5.6 7.0 -14×10R 1D 2016 [22] 2016 [23] 2017 [24] IWV Ge-IWV 9.8 12x12R 1D 2021 [25] PTF PST-35 3.9 10x8×8R 1D 2022 [26] PSL IWW ITQ-22 4.0 12×10×8R 1D Porous sparse layers 2003 [27] IWR ITQ-24 9.5 12×10R 1D 2003 [28] ITH Ge-ITQ-13 > 6.0 10×10×9R 1D 2006 [29] ITR ITQ-34 9.0 10×10×9R 1D 2008 [30] SVV SSZ-77 4.4 6R 1D 2008 [31] ITG ITQ-38 4.5 12×10×10R 1D 2012 [32] UOV IM-17 3.5 12×10×8R 1D 2014 [33] -SU-78 2.4 12×12×12R 1D 2012 [34] HPM-8 7.3 2019 [35] -ECNU-13P 6.0…”