Explanation of the adsorption of polar vapors in the highly flexible metal organic framework MIL-53(Cr).
A comparison of the adsorption of water, methanol, and ethanol polar vapors by the flexible porous chromium(III) terephthalate MIL-53(Cr) was investigated by complementary techniques including adsorption gravimetry, ex situ X-ray powder diffraction, microcalorimetry, thermal analysis, IR spectroscopy, and molecular modeling. The breathing steps observed during adsorption strongly depend on the nature of the vapor. With water, a significant contraction of the framework is observed. For the alcohols, the initial contraction is followed by an expansion of the framework. A combination of IR analysis, X-ray diffraction, and computer modeling leads to the molecular localization of the guest molecules and to the identification of the specific guest-guest and host-guest interactions. The enthalpies of adsorption, measured by microcalorimetry, show that the strength of the interactions decreases from ethanol to water. Differential scanning calorimetry experiments on an EtOH/H(2)O mixture suggest a selective adsorption of ethanol over water.
Bourrelly
Sandrine
S
Laboratoire Chimie Provence, UMR 6264, Universités Aix-Marseille I, II & III-CNRS, Centre de Saint Jérôme, 13397 Marseille cedex 20, France.
Moulin
Béatrice
B
Rivera
Angel
A
Maurin
Guillaume
G
Devautour-Vinot
Sabine
S
Serre
Christian
C
Devic
Thomas
T
Horcajada
Patricia
P
Vimont
Alexandre
A
Clet
Guillaume
G
Daturi
Marco
M
Lavalley
Jean-Claude
JC
Loera-Serna
Sandra
S
Denoyel
Renaud
R
Llewellyn
Philip L
PL
Férey
Gérard
G