Synthesis of STW zeolites using imidazolium-based dications of varying length

doi:10.1039/c7ta10002g

	Synthesis of STW zeolites using imidazolium-based dications of varying length
	Lu, Peng 1,2,3; Gomez-Hortiguela, Luis 4; Xu, Lei 1; Camblor, Miguel A.3
刊名	JOURNAL OF MATERIALS CHEMISTRY A
	2018-01-28
卷号	6 期号:4 页码:1485-1495
ISSN号	2050-7488
DOI	10.1039/c7ta10002g
文献子类	Article
英文摘要	Dications consisting of 1,2-dimethylimidazolium units linked by chains of 4, 5 or 6 methylene groups display structure direction towards the chiral zeolite STW as racemic conglomerates with decreasing strength as the length of the linker increases. A phase transformation from the denser and less strained MTW to the less dense and more strained STW reveals significant stabilization in the case of the 4-methylene dication, which is able to produce STW even in the absence of germanium (i.e., for a pure silica composition), and to a lesser extent for the 5-methylene derivative. When Ge is introduced in the synthesis the crystallization is easier and the crystallization field is wider, with Ge preferentially occupying positions at the double four ring units of the STW framework, as revealed by Rietveld refinement from synchrotron data. Quantum mechanics calculations show that the interaction energy diminishes as the length of the linker increases, in agreement with the experimental findings. In addition, calculation of the C-13 NMR chemical shieldings and comparison with experimental spectra allowed us to identify different conformations and orientations of the imidazolium rings in the asymmetric STW cavities, depending on the spacer length. An exploratory study strongly suggests that an asymmetric derivative with additional methyl groups at both sides of the tetramethylene chain could afford the crystallization of the homochiral zeolite even as a pure silica material.
WOS关键词	STRUCTURE-DIRECTING AGENTS ; IN-SITU TRANSFORMATION ; MOLECULAR-SIEVES ; FLUORIDE MEDIA ; LESS DENSE ; FRAMEWORK ; SILICA ; ITW ; CATIONS ; SIO2
WOS研究方向	Chemistry ; Energy & Fuels ; Materials Science
语种	英语
出版者	ROYAL SOC CHEMISTRY
WOS记录号	WOS:000423466100016
内容类型	期刊论文
源URL	[http://cas-ir.dicp.ac.cn/handle/321008/168580]
专题	大连化学物理研究所_中国科学院大连化学物理研究所
通讯作者	Camblor, Miguel A.
作者单位	1.Chinese Acad Sci, Dalian Natl Lab Clean Energy, Dalian Inst Chem Phys, Dalian 116023, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 3.CSIC, ICMM, C Sor Juana Cruz 3, Madrid 28049, Spain 4.CSIC, ICP, C Marie Curie 2, Madrid 28049, Spain
推荐引用方式 GB/T 7714	Lu, Peng,Gomez-Hortiguela, Luis,Xu, Lei,et al. Synthesis of STW zeolites using imidazolium-based dications of varying length[J]. JOURNAL OF MATERIALS CHEMISTRY A,2018,6(4):1485-1495.
APA	Lu, Peng,Gomez-Hortiguela, Luis,Xu, Lei,&Camblor, Miguel A..(2018).Synthesis of STW zeolites using imidazolium-based dications of varying length.JOURNAL OF MATERIALS CHEMISTRY A,6(4),1485-1495.
MLA	Lu, Peng,et al."Synthesis of STW zeolites using imidazolium-based dications of varying length".JOURNAL OF MATERIALS CHEMISTRY A 6.4(2018):1485-1495.