Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
Dynamics of xylene isomers in MIL-53 (Al) MOF probed by solid state 2H NMR. / Khudozhitkov, Alexander E.; Arzumanov, Sergei S.; Kolokolov, Daniil I. и др.
в: Microporous and Mesoporous Materials, Том 300, 110155, 15.06.2020.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Dynamics of xylene isomers in MIL-53 (Al) MOF probed by solid state 2H NMR
AU - Khudozhitkov, Alexander E.
AU - Arzumanov, Sergei S.
AU - Kolokolov, Daniil I.
AU - Stepanov, Alexander G.
N1 - Funding Information: This work was supported by Russian Foundation for Basic Research (grant № 18-29-04009 ) and in part by the Ministry of Science and High Education of the Russian Federation (Project no. AAAA-A17-117041710084-2 ). DIK also acknowledges the support from the Russian Science Foundation , project № 17-73-10135 . Publisher Copyright: © 2020 Elsevier Inc. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2020/6/15
Y1 - 2020/6/15
N2 - With regard to understanding the effect of the dynamics of xylenes confined in the MOFs pores on the origin of xylene isomers separation, the mobility of para and ortho isomers of xylene in MIL-53(Al) MOF has been studied by solid-state 2H NMR. It is inferred that both isomers perform rotational and librational motions of the aromatic ring plane. The geometry, rates and energy barriers of the detected rotational modes for the molecules confined in the channels have been determined. The rotation around the axis perpendicular to the plane of aromatic ring is obliged with pairwise arrangement of xylene molecules along 1D channels of the MOF. The evolution of motional patterns with temperature shows that the pairwise arrangement of ortho isomer in the channels is held till 300 K, whereas the pairs are stable up to 405 K for the para isomer. This was rationalized by stronger interaction of o-xylene with the channel walls, while π–π intermolecular interaction is stronger for p-xylene. Due to stronger interaction between the unpaired molecules and MOF walls o-xylene exhibits notably higher temperature of the molecules desorption from the channels (494 K). In contrast, the p-xylene is capable to leave the channels of MIL-53 already at 405 K, moving in the channels predominantly in pairs. The different motional behavior of xylene isomers provides the conditions for a faster translational mobility along the MOF channel of para compared to the ortho isomer, thus accounting for the molecular mechanism behind the separation selectivity for xylene isomers.
AB - With regard to understanding the effect of the dynamics of xylenes confined in the MOFs pores on the origin of xylene isomers separation, the mobility of para and ortho isomers of xylene in MIL-53(Al) MOF has been studied by solid-state 2H NMR. It is inferred that both isomers perform rotational and librational motions of the aromatic ring plane. The geometry, rates and energy barriers of the detected rotational modes for the molecules confined in the channels have been determined. The rotation around the axis perpendicular to the plane of aromatic ring is obliged with pairwise arrangement of xylene molecules along 1D channels of the MOF. The evolution of motional patterns with temperature shows that the pairwise arrangement of ortho isomer in the channels is held till 300 K, whereas the pairs are stable up to 405 K for the para isomer. This was rationalized by stronger interaction of o-xylene with the channel walls, while π–π intermolecular interaction is stronger for p-xylene. Due to stronger interaction between the unpaired molecules and MOF walls o-xylene exhibits notably higher temperature of the molecules desorption from the channels (494 K). In contrast, the p-xylene is capable to leave the channels of MIL-53 already at 405 K, moving in the channels predominantly in pairs. The different motional behavior of xylene isomers provides the conditions for a faster translational mobility along the MOF channel of para compared to the ortho isomer, thus accounting for the molecular mechanism behind the separation selectivity for xylene isomers.
KW - H NMR
KW - Dynamics
KW - MIL-53
KW - MOF
KW - Xylene
KW - P-XYLENE
KW - MOBILITY
KW - WATER DYNAMICS
KW - MIXTURES
KW - EQUILIBRIA
KW - DIFFUSION
KW - H-2 NMR
KW - SEPARATION
KW - LIQUID-PHASE ADSORPTION
KW - PAREX PROCESS
KW - ZEOLITE
UR - http://www.scopus.com/inward/record.url?scp=85081678141&partnerID=8YFLogxK
U2 - 10.1016/j.micromeso.2020.110155
DO - 10.1016/j.micromeso.2020.110155
M3 - Article
AN - SCOPUS:85081678141
VL - 300
JO - Microporous and Mesoporous Materials
JF - Microporous and Mesoporous Materials
SN - 1387-1811
M1 - 110155
ER -
ID: 23802352