ethylene oxychlorination catalysis - role of metal promoters on activity and selectivity of the...
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8/13/2019 Ethylene Oxychlorination Catalysis - Role of Metal Promoters on Activity and Selectivity of the Process
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n” Ethylene oxychlorination catalysis: role of metal
promoters on activity and selectivity of the process”
Naresh.B.Muddada, U. Olsbye, C. Lamberti, T. Fuglerud
Trondheim, 3rd Nov ’11
8/13/2019 Ethylene Oxychlorination Catalysis - Role of Metal Promoters on Activity and Selectivity of the Process
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The chemistry of PVC and origin ofOxychlorination process
Ethylene Oxychlorinationcatalyst - state of art
Influence of additives on base catalyst:multi technique approach
Summary &Conclusions
Outlook
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PVCPolymerisation
Direct chlorination (FeCl3)C2H4 + Cl2 C2H4Cl2
Cracking of 1,2-dichloroethane (EDC)C2H4Cl2 CH2=CHCl+ HCl
Poly Vinyl-Chloride (PVC)
Oxychlorination reaction (CuCl2) @ 230ºCC2H4 + 2HCl + ½ O2 C2H4Cl2 + H2O
PVC industry is growing market with recycling efforts
8/13/2019 Ethylene Oxychlorination Catalysis - Role of Metal Promoters on Activity and Selectivity of the Process
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The basic commercial catalyst is CuCl2/ γ-Al
2O
3
Oxychlorination Catalyst – State of Art
Catalyst
bed
HCl
C2H4
N2
Air
C2H4Cl2
C2H3Cl
C2H5Cl2
C2H3Cl3
CO2
Desired Product
300 ºC
Fixed bed reactor
X
8/13/2019 Ethylene Oxychlorination Catalysis - Role of Metal Promoters on Activity and Selectivity of the Process
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Reaction mechanism
Promotes EDC
degradation
Promotes
ethylene burn
Promotes over-
chlorination2 CuCl2 Cu2OCl2
2 CuCl
C2H4
C2H4Cl2 ½ O2
2 HClH2O
Hydrochlorolysis
ChlorinatedBy-products
Acid sitesCuCl responsible for Cu-migration
CuCl2 responsible for particle agglomeration
8/13/2019 Ethylene Oxychlorination Catalysis - Role of Metal Promoters on Activity and Selectivity of the Process
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Adding dopants may solve the above problems
Economic prospect: Drive to decrease operation costs
Motivation & Challenges
Chemical & Environmental prospect: selectivity could
still be improved
CuClx is volatile and may be lost during reaction
Hot spots, thermo –chemical side reactions
Catalyst becomes sticky under certain reaction
conditions (Fluid bed operation)
8/13/2019 Ethylene Oxychlorination Catalysis - Role of Metal Promoters on Activity and Selectivity of the Process
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Our aim is very ambitious and can be summarized in the
following four main points:
Doped catalyst
Reactants
1) Influence on Surface and its propertiesDispersion, active phase modifictaion, acidity of the surface….
2) Influence on reaction mechanismand kinetics
3) Influence on thermal & mechanical
stability of the catalyst during reaction
4) Influence on Selectivity
Objective
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Reactants
Kinetic tests
A c t i vi t y
&
S el e c t i vi t y
Doped
Catalyst
In-situ mode or Operando
mode
Influence of Additivies
Characterisation using combined spectroscopy
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Influence of Additives: On the Support
Modification on Surface acidity upon addition of dopant & chlorine
Unwanted species
N. B. Muddada et al ., J.Catal (2011) accepted
H -Cl
H2O
>Al-O-Al< +HCl >Al-OH + Cl-Al<
>Al-OH + HCl >Al-Cl + H2O
1)
H2O
CuCl2 + MClx 2)
8/13/2019 Ethylene Oxychlorination Catalysis - Role of Metal Promoters on Activity and Selectivity of the Process
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Fourier Transform Infrared Spectroscopy
FTIR: a surface technique, basically give information about surface species
Peak position,
intensity and width
=>
Nature of species
I/I0 = %T
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2200 2150 2100
0.2 a.u.
Al2O3
2183
2154
a b s o r b a n c e u n i t s ( a . u . )
0.2 a.u.
Wavenumber (cm-1
)2200 2150 2100
0.2 a.u.
2182
2158Cu
5.0
2129
2200 2150 2100
2183
2158Cl2.8A
Influence of Additives: The Surface
CO adsorbed FTIR
FTIR
Evolution of the CO
adsorbed FTIR spectra
on the fresh catalyst
activated @230° C under
vaccum.
Lewis acid sites:
[= Al3+ ] …. CO
Brønsted acid sites
[= Al-OH] ….. CO
N. B. Muddada et al ., J.Catal (2011), in press.
O
C
O
C
8/13/2019 Ethylene Oxychlorination Catalysis - Role of Metal Promoters on Activity and Selectivity of the Process
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0.5 a.u.
Li0.5Cu5.0
2158
2128
n o r m a l i s e d A b s o r b a n c e ( a . u . )
0.5 a.u.
K 3.1Cu5.0
2123
2157
2118
Cs10.4Cu5.0
0.5 a.u.
2154
2200 2150 2100
0.5 a.u.
Mg1.9
Cu5.0
2127
2158
2200 2150 2100
0.5 a.u.
Ca3.2
Cu5.0
21322159
Wavenumber (cm-1
)
2200 2150 2100
0.5 a.u.
21352163
La10.9
Cu5.0
Influence of Additives: On the Surface
O
C
Al3+
O
C
Cu+
O
C
Al
OH
CO adsorbed FTIR
Most of Lewis sites are
compressed
Strength of Brønsted
sites follows the order:
La > Ca > Mg > Li >
Cu > K > Cs
Catalyst: doped CuCl2/ -Al2O3
N. B. Muddada et al ., J.Catal (2011), in press
8/13/2019 Ethylene Oxychlorination Catalysis - Role of Metal Promoters on Activity and Selectivity of the Process
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k kR senee
R
k A N S k
s s
k
R
s s
s s s
s
2
2 222
2
2
2
0
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1 2 3
i m g ( F
T )
R (Ao)
| F T |
EXAFS
Evolution of the
EXAFS spectra of
the fresh catalyst
activated @ 230° C
Collected at EAXFS 13, LURE, France
Influence of Additives: On the Cu phase
N. B. Muddada et al ., Dalton Tran, 39 (2010) 8437.
Extended X-Ray Absorption Fine Spectroscopy
Cu 1.4Cu 1.4
Cu 5.0
Cu 1.4
Cu 5.0
La10.9Cu 5.0
Li0.5Cu 5.0
Mg1.9Cu5.0
K 3.1
Cu5.0Cs10.4Cu5.0
Cu-O
Cu-Cl
La>Li>Mg>K>Cs>Cu
All dopants are competing with Cu to occupy alumina octahedral vacancy sites
8/13/2019 Ethylene Oxychlorination Catalysis - Role of Metal Promoters on Activity and Selectivity of the Process
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Influence of Additives: Kinetics
Kinetic
tests
Evolution of the products
(by GC-MS) of the sieved
catalyst interacted with
reaction mixture @
230° C - 350° C under
steady state
Byproduct formation follows the order
Cu5.0
> La10.9
Cu5.0
> Li0.5
Cu5.0
> Mg1.9
Cu5.0 > K 3.1
Cu5.0
≈ Cs10.4
Cu5.0
N. B. Muddada et al ., J.Catal (2011) accepted
230°C 270°C 300°C 350°C
0,0
0,1
0,2
r e l a t i v e
a m o u n t o f b y - p
r o d u c t s / E D C
Temperature
Cu5.0 Li0.9Cu5.0
La10.9Cu5.0
Mg1.9Cu5.0
K3.1Cu5.0
Cs10.4Cu5.0
”It is evident that dopants had an influence on
activity & in controlling the by-products”
8/13/2019 Ethylene Oxychlorination Catalysis - Role of Metal Promoters on Activity and Selectivity of the Process
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Summary & Conclusions
Chlorine has significant influence on acidity of alumina surface.
Dopant metals also influence the acidity of alumina especially in case of Lewis sites.
Dopants increase the fraction of copper specieis on the surface.
Dopants had a significant influence on activity and also in controlling the by- product formation
compared to base catalyst CuCl2/ -Al
2O
3.
Acidity
% Cu(II)Dopant
Cu(II)/Cu(I)Activity &
Selectivity
8/13/2019 Ethylene Oxychlorination Catalysis - Role of Metal Promoters on Activity and Selectivity of the Process
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Acknowledgments
University of Torino
Prof. Carlo LambertiProf. Silvia BordigaDr. Elena GroppoDiego Gianolio
Prof. Adriano ZecchinaLab Colleagues
University of Bologna
Prof. Fabrazio CavaniProf. L.Caccialupi
University of Oslo
Prof. Unni OlsbyeSharmala Arvindthan
INEOS (Norway & Italy) Terje Fuglerud
Andrea MarsellaSandra Vidotto
ConsultantGiuseppe Leofanti
hanks for yourttention……
8/13/2019 Ethylene Oxychlorination Catalysis - Role of Metal Promoters on Activity and Selectivity of the Process
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Different Supports
Possible Supports:
Zr-MOF (UIO-66) - An ultra stable Metal Organic Framework (MOF)
Alumina modified with CeO2 .
Mixed metal oxides: CeZrOx, Mg10 Al7Ox.
Perovskite materials , Zeolite type materials.
Possible Supports:
Zr-MOF (UIO-66) - An ultra stable Metal Organic Framework (MOF)
Alumina modified with CeO2 .
MIxed metal oxides: CeZrOx,
Mg10
Al7O
x,
Perovskite materials, Zeolites type materials.
UIO-66: Commerically available Zr- MOF
8/13/2019 Ethylene Oxychlorination Catalysis - Role of Metal Promoters on Activity and Selectivity of the Process
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In-situ EXAFS+MS set-up
CuCl2 was loaded during synthesis of Zr-MOF ( uio-66)
SNBL - ESRF
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-- @RT
-- @RT-200 C
-- @200C-- @rxmx_200C
-- @rxmx_200C
-- cooling down
-- cooling downCu+
Cu2+
CuCl2-Zr-MOF as redox catalyst - XANES
Ethylene+HCl+Air Mass Spec
Conversion isvery very low!!!
Cu wt% ≈ 1,2 %
CuCl
CuCl2
Cu-MOF is showing red-ox proporties…
CuMOF : CuCl2 loaded onto Zr-MOF
8/13/2019 Ethylene Oxychlorination Catalysis - Role of Metal Promoters on Activity and Selectivity of the Process
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CuMOF_RT_2
Lin(Counts)
0
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
2500
2-Theta - Scale
3 10 20 30 4
CuMOF-@ RT and 160 C
With reaction mixture
Collapsing after interaction with reaction mixture….!!!
CuMOF : CuCl2 loaded onto Zr-MOF
CuCl2-Zr-MOF as redox catalyst - XRD
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CuMOF_RT
Lin(Counts
)
0
1000
2000
3000
2-Theta - Scale
3 10 20 30 4
CuMOF- gas. HCl
Cu-MOF+HCl@ 100 ºC
Cu-MOF+HCl@ 120 ºC
The structure started collapsing upon
interaction with HCl at 120 ºC
CuCl2-Zr-MOF + gas. HCl - XRD
Cu-MOF+HCl @ RT