Chinese Journal of Catalysis ›› 2021, Vol. 42 ›› Issue (9): 1468-1477.DOI: 10.1016/S1872-2067(20)63777-9

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Organic-free synthesis of MOR nanoassemblies with excellent DME carbonylation performance

Kaipeng Caoa,b, Dong Fana, Shu Zenga,b, Benhan Fana,b, Nan Chena,b, Mingbin Gaoa,b, Dali Zhua,b, Linying Wanga, Peng Tiana,*(), Zhongmin Liua,b,#()   

  1. aNational Engineering Laboratory for Methanol to Olefins, Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China
    bUniversity of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2020-11-19 Accepted:2021-02-02 Online:2021-09-18 Published:2021-05-16
  • Contact: Peng Tian,Zhongmin Liu
  • About author:# E-mail: liuzm@dicp.ac.cn
    * E-mail: tianpeng@dicp.ac.cn;
  • Supported by:
    National Natural Science Foundation of China(21676262);National Natural Science Foundation of China(21991090);National Natural Science Foundation of China(21991091);Key Research Program of Frontier Sciences, Chinese Academy of Sciences(QYZDB-SSW-JSC040);funding from the French-Sino International Laboratory (LIA) “Zeolites”

Abstract:

Seed-assisted low alkalinity gel system was developed to explore the organic-free synthesis of MOR zeolite. MOR nanoassemblies with Si/Al ratio (SAR) up to 9.4 and high solid yield (84-94%) were successfully obtained under controlled low alkalinity conditions. Characterization results demonstrate that the acid strength increases in parallel with the SAR, while the total acid amount and the proton distribution in the main channels and the side pockets are similar for the samples. The proton distribution in the H-MOR is not straightforwardly related to the Na+ distribution in the as-synthesized MOR, implying the transfer of the protons among the oxygen sites of framework T atom. Relative to low-silica samples I-5.3 and I-7.4, sample I-9.4 displays the best mass transfer performance and accessibility of the acid sites by pyridine due to its relatively low Al density and mild dealumination degree. Correspondingly, sample I-9.4 (pyridine-modified catalyst) shows the best activity with ca. 100% selectivity of methyl acetate (MAc) in the DME carbonylation reaction. The high steady MAc yield (6.8 mmol/g/h) over sample I-9.4 suggests the promising application of MOR nanoassemblies synthesized by this economical organic-free strategy.

Key words: MOR zeolite, Organic-free synthesis, DME carbonylation, Acidity, Diffusion