4th EucheMs chemistry congress

Poster Session 2
s1199
chem. Listy 106, s257–s1425 (2012)
Poster session 2 - solid state chemistry
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orGAniC SuPerConduCtinG MAteriALS –
reCent reSuLtS
h. MueLLer 1 , S. Brun 2 , M. hAnfLAnd 2
1 European Synchrotron Radiation Facility, Chemistry & Micro-
Imaging Laboratories, Grenoble cedex 9, France
2 European Synchrotron Radiation Facility, Beamline ID09 A,
Grenoble cedex 9, France
This work addresses the chemistry and selected physical
properties of organic, super-conducting radical cation salts derived
from bis(ethylenedithiolo)tetrathiafulvalene (BEDT-TTF or ET).
The following topics of general and recent interest will be
highlighted in more detail:
Use of X-ray microcrystal diffraction and high resolution
powder diffraction techniques for a better understanding of the
properties of organic superconducting materials.
Organic superconductors under high pressure – crystallographic
evidence for the existence of a new polymorphic phase
of α-(ET) I at high pressure.
2 3
Keywords: superconductors;
4 th EucheMs chemistry congress
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enthALPy-entroPy CoMPenSAtion for n o 2
And Co AdSorPtion on zSM-5 ContAininG
trAnSition MetAL ionS
r. herCiGonJA 1 , v. rAKiC 2 , v. rAC 2 , A. Auroux 3
1 Faculty of Physical Chemistry University of Belgrade, Faculty
of Physical Chemistry, Belgrade, Serbia
2 Faculty of Agriculture University of Belgrade, Faculty of
Agriculture, Belgrade, Serbia
3 Institut de recherches sur la catalyse et l’environnement de
Lyon Université Lyon, Institut de recherches sur la catalyse et
l’environnement de Lyon, Lyon, France
The “enthalpy-entropy compensation” phenomenon refers
to the linear scaling between enthalpy (ΔH) and entropy (ΔS) for
a set of related reactions. At the “compensation temperature” any
variation in enthalpy is balanced by such variation in entropy so
that the total change in free energy remains constant [1] .
There is a growing interest in manganese incorporation in
zeolite lattices, mainly because of the role of this metal in
numerous metallo-enzymes. Also, Mn2+ is a very active catalyst
for SO oxidation in aqueous phase.
2
In this work, thermodynamic parameters and the existence
of enthalpy-entropy compensatory behaviour in adsorption of N O 2
and CO on Mn2+ exchanged ZSM-5 zeolites, and bi-metallic
FeMnZSM-5 and CuMnZSM-5 were investigated. The changes
of entropy caused by N O and CO adsorption were calculated
2
from differential heats [1].
The N O and CO adsorption was investigated by
2
microcalorimetry and FTIR spectroscopy. Heats of adsorption
were measured at 303 K in a heat-flow microcalorimeter
(C80 Setaram) linked to a glass volumetric line. FTIR spectra
were recorded using FTIR Brucker spectrometer with OPUS 22
software.
Existence of enthalpy-entropy compensation effect was
evidenced by the linearity of –ΔH vs. –ΔS plots with the
correlation coefficients 0.99, characteristic for all investigated
zeolites, expect for CO adsorption on CuMnZSM-5. It was found
that compensation effect depends on the type of charge-balancing
cation. The compensation effect is governed by electrostatic
interactions between highly polarizing cationic centres in zeolite
and N O and CO molecules (depending of the size and charge of
2
the cation) and by specific interactions (depending of the electron
configuration of the cation).
Existence of the compensation effect is of interest for the
possibility of predicting adsorption behaviour of the system and
providing data for the zeolite as a catalyst.
references:
1. R. Hercigonja, V. Rac, V. Rakic, A. Auroux, J. Chem.
Therm. 48 (2012) 112-117.
Keywords: Adsorption; Zeolites; Thermodynamics;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc