Ionothermal synthesis, physicochemical characterization and catalytic performance of extra-large-pore silicoaluminophosphate zeotype with -CLO structure

Meng, Xiangzhi; Guo, Ke; Lin, Yutong; Wang, Hao; Chen, Hongxia; Huang, Pengfei; Tao, Shuo; Zhang, Ling; Wei, Ying; Zhang, Runduo

doi:10.1007/s10934-021-01106-z

Cited by 6 publications

(11 citation statements)

References 35 publications

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“…Molecular simulation result (Figure 2 and Table S1) indicated that as compared with TMA + /TPA + /TBA + , TEA + similar with [emim] + is energetically favorable as guest occluded in clo and lta cages, with 1, 2 and 14 TEA + in each clo , lta and super cage, respectively. N 2 physisorption (Figure S10) revealed that TEA + could be removed by high temperature calcination, giving rise to excellent porosity with large BET surface area of 660 m 2 /g, high microporous volume of 0.23 cm 3 /g and wide pore size distribution between 0.8 and 1.4 nm in accordance with the unique four‐leafed clover shape of the 20‐ring pore opening [8d] …”

Section: Resultsmentioning

confidence: 91%

“…Further prolonging the synthesis time, the intensity of these diffraction peaks were improved and reached maximum at about 2 h. SEM images (Figure S11) showed that the 0–40 min samples were accumulated small particles with irregular morphology, which became more regular and dispersed at 60 min. At 80 and 120 min, more large cubic crystals were clearly observed, corresponding to the further growth of DNL‐1 [8d,e] …”

Section: Resultsmentioning

confidence: 99%

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Solvent‐Free Thermal Synthesis of Extra‐Large‐Pore Aluminophosphate Zeotype via Self‐Assembly of Double‐Four‐Ring Unit

Huang

Wei

Hou

et al. 2022

Chemistry A European J

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The use of Ge as framework atom to direct the formation of double-four-ring (d4r) unit is an effective way to prepare zeolite with extra-large pores, which however also brings about serious problems with regard to production cost and structure stability for their practical application. A new solvent-free thermal synthesis strategy is presented here for facile preparation and molecular-level mechanism study of extra-large-pore aluminophosphate zeotype DNL-1 with -CLO structure. For the first time, the formation of intermediate d4r in the induction period was successfully confirmed, and was correlated with the synthesis condition of low water content and quaternary ammonium template with suitable alkyl chain length. The self-assembly pathway via d4r to form lta, afterwards clo and super cages was further revealed. This work shed light on the rational synthesis of Ge-free extralarge-pore zeotypes based on d4r route.

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Section: Resultsmentioning

confidence: 91%

Section: Resultsmentioning

confidence: 99%

Solvent‐Free Thermal Synthesis of Extra‐Large‐Pore Aluminophosphate Zeotype via Self‐Assembly of Double‐Four‐Ring Unit

Huang

Wei

Hou

et al. 2022

Chemistry A European J

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“…28 The 29 Si MAS NMR spectrum of sample V-0.15T/0.3S also shows a small resonance peak at −94 ppm, corresponding to the coordination structure of Si (3Al), formed by the double substitution of a pair of neighboring Al and P by two Si (SM III). 29 It showed that when the ratio of SiO 2 /Al 2 O 3 was 0.3, both SM II and SM III substitution occurred. The distribution of silicon was mainly Si (4Al), accompanied by a small amount of a Si (3Al) coordination structure.…”

Section: ■ Results and Discussionmentioning

confidence: 98%

“…The 29 Si MAS NMR spectrum (Figure 9A) shows a strong resonance peak at −91.6 ppm, corresponding to the coordination structure of Si (4Al). 27 The phenomenon can be attributed to the replacement of P by Si (SM II).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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A Green and Cost-Effective Synthesis of Hierarchical SAPO-34 through Dry Gel Conversion and Its Performance in a Methanol-to-Olefin Reaction

et al. 2021

Ind. Eng. Chem. Res.

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In this work, a low-cost and high-performance methanol-to-olefin (MTO) catalyst was synthesized by dry gel conversion (DGC). Using tetraethylammonium hydroxide (TEAOH) as the structure-directing agent (SDA) to prepare the dry gel, nano-SAPO-34 in a range of 50−500 nm was synthesized under the effect of the vapor of triethylamine (TEA) and H 2 O. The TEAOH consumption using this method was only 7.5% of that in the hydrothermal synthesis (HTS), and the yield of nano-SAPO-34 products was up to 94%. When scaling up to the pilot test, obvious heterocrystals appeared with the decrease in SiO 2 content in the dry gel. Our results showed that the heterocrystals were completely eliminated after the introduction of fluoride into the dry gel. A low acid density nanosheet-SAPO-34 molecular sieve product with good micropore, mesopore, and macropore connectivity was obtained. The obtained multikilogram-scale molecular sieve sample can be directly shaped to obtain MTO microsphere catalysts by spray drying without separation and washing. No wastewater was produced during the whole process, demonstrating an entirely green production way. The MTO performance of the microsphere catalysts was tested in a fluidized bed reactor, and results showed that the catalysts exhibited the characteristics of a slow carbon deposition rate and a high activity utilization ratio. Their lifetime was extended by 14%, and their selectivity (C 2 = + C 3 = ) was increased by 1.55%, so they are very suitable for industrial application. This work has provided the theoretical and practical basis for the industrial production and application of DGC in the future.

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Synthesis and Applications of SAPO‐34 Molecular Sieves

Cheng

et al. 2021

Chemistry A European J

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Silicoaluminophosphate zeolite (SAPO‐34) has been attracting increasing attention due to its excellent form selection and controllability in the chemical industry, as well as being one of the best industrial catalysts for methanol‐to‐olefin (MTO) reaction conversion. However, as a microporous molecular sieve, SAPO‐34 easily generates carbon deposition and rapidly becomes inactivated. Therefore, it is necessary to reduce the crystal size of the zeolite or to introduce secondary macropores into the zeolite crystal to form a hierarchical structure in order to improve the catalytic effect. In this review, the synthesis methods of conventional SAPO‐34 molecular sieves, hierarchical SAPO‐34 molecular sieves and nanosized SAPO‐34 molecular sieves are introduced, and the properties of the synthesized SAPO‐34 molecular sieves are described, including the phase, morphology, pore structure, acid source, and catalytic performance, in particular with respect to the synthesis of hierarchical SAPO‐34 molecular sieves. We hope that the review can provide guidance to the preparation of the SAPO‐34 catalysts, and stimulate the future development of high‐performance hierarchical SAPO‐34 catalysts to meet the growing demands of the material and chemical industries.

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Ionothermal synthesis, physicochemical characterization and catalytic performance of extra-large-pore silicoaluminophosphate zeotype with -CLO structure

Cited by 6 publications

References 35 publications

Solvent‐Free Thermal Synthesis of Extra‐Large‐Pore Aluminophosphate Zeotype via Self‐Assembly of Double‐Four‐Ring Unit

Solvent‐Free Thermal Synthesis of Extra‐Large‐Pore Aluminophosphate Zeotype via Self‐Assembly of Double‐Four‐Ring Unit

A Green and Cost-Effective Synthesis of Hierarchical SAPO-34 through Dry Gel Conversion and Its Performance in a Methanol-to-Olefin Reaction

Synthesis and Applications of SAPO‐34 Molecular Sieves

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