4th EucheMs chemistry congress

thursday, 30-Aug 2012
s662
chem. Listy 106, s587–s1425 (2012)
Environment and Green Chemistry
Green Chemistry – iV
o - 4 3 4
trACeS of deGrAdAtion By PyroLySiS under
uLtrASound: it’S GettinG hot in ioniC
LiquidS!
G. ChAteL 1 , r. PfLieGer 2 , e. nAffreChoux 1 ,
S. niKitenKo 2 , J. SuPtiL 1 , C. Goux-henry 3 ,
n. KArdoS 1 , B. AndrioLetti 3 , M. drAye 1
1 Université de Savoie, LCME, Le Bourget du Lac, France
2 Institut de Chimie Séparative de Marcoule, ICSM, Bagnolssur-Ceze,
France
3 Université de Lyon I, CASYEN, Villeurbanne, France
More than eight decades after the discovery of
ultrasound-induced chemical processes, known as sonochemistry,
they remain a subject of attractive research. It is generally
accepted that the chemical effects of ultrasound result from the
phenomenon of acoustic cavitation, which is the formation,
growth and collapse of bubbles in an elastic liquid. By imploding,
these bubbles create locally extreme conditions that can lead to
high-energy radical mechanisms but also generate some
interesting physical effects that can improve catalyst activity.
Since the use of ionic liquids in organic chemistry as
solvents and/or as catalysts and since the development of organic
sonochemistry, the combination of these two technologies has
presented unsuspected and very beneficial effects for certain
organic reactions. However, the effects of ultrasound on ionic
liquids are unknown, except the observation of a darkening of the
ionic liquid of the study by several research groups.
For the first time, we have determined the origin of this
coloration through the behaviour of hydrophobic ionic liquids to
the phenomenon of cavitation. We have studied the
sonoluminescence of pyrrolidinium and piperidinium ionic
liquids. We have identified, from recent and advanced analytical
methods, the main traces of degradation products in order to
propose mechanisms of degradation of ionic liquids under
ultrasound. Moreover, we have developed a simple and
convenient method to significantly reduce the impact of
ultrasound on ionic liquids and thus protect them from
degradation. For the first time, we determine the acoustic power
when they are submitted to ultrasound. Ionic liquids heat up
almost three times faster than water leading to interesting effects
as solvent for organic reactions.
Our original studies present a real important impact for
researchers for a better understanding of ionic liquids/ultrasound
combination for various organic chemistry applications, and not
only for specialized scope.
Keywords: ionic liquids; analytical methods; green chemistry;
Green Chemistry – iV
4 th EucheMs chemistry congress
o - 4 3 5
PhASe equiLiBriA of CLAthrAte hydrAteS
SuitABLe for CArBon dioxide CAPture
K. iino 1 , t. SuGinAKA 1 , h. SAKAMoto 1 ,
r. ohMurA 1
1 Keio university, science and engineering, Yokohama, Japan
This study is concerned with the technology for CO2 separation from gas mixture utilizing clathrate hydrate
formation/dissociation. CO separation may be applied for flue
2
gas from combustion power plants (CO and N mixture) or for
2 2
unconventional natural gas such as coal bed methane and biogas
(CO and CH mixture). The obstacle of this hydrate technology
2 4
is high pressure for hydrate formations. Hence, it is favorable to
moderate equilibrium conditions by adding hydrate formation
promoters such as ionic guest substances which form
semiclathrate hydrates. In the present study, ionic guest substances
were selected based on the following three requirements:
(a) moderate the equilibrium conditions, (b) non-toxic,
non-flammable and non-corrossive effect on metal and (c) store
large amounts of gas. Among the selected candidate guests, we
particularly focused on tetrabutylphosphonium bromide (TBPB)
hydrate and tetrabutylphosphonium chloride (TBPC) hydrate.
This paper reports an experimental study on the phase equilibrium
measurements in three-component systems of (CO , CH or
2 4
N + TBPB + water) and (CO or CH + TBPC + water). These
2 2 4
experimental data were measured by isochoric method in the
pressure (p) range of (0.1 to 2.1 MPa) and temperature (T) range
of (282 to 289 K) at mass fraction 0.35 for TBPB and 0.36 for
TBPC. The measurement uncertainties were ±0.1 K for T,
±5.0 kPa for p, and ±1.0×10-4 for mass fraction of each species in
the liquid phase. It was found that equilibrium conditions for the
(CO or CH + water) systems were more moderated by TBPB
2 4
than by TBPC. The results also indicated that TBPB was better
ionic guest substance for CO separation from CO and CH 2 2 4
mixture than TBPC.
Keywords: Clathrates; Hydrates; Carbon dioxide fixation;
Green chemistry; Phase diagrams;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc