Ethylene oxychlorination n promoters on activity and selectivity of … · 2014-11-17 ·...
Transcript of Ethylene oxychlorination n promoters on activity and selectivity of … · 2014-11-17 ·...
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
The chemistry of PVC and origin of Oxychlorination process
Ethylene Oxychlorination catalyst - state of art
Influence of additives on base catalyst: multi technique approach
Summary & Conclusions
Outlook
PVC Polymerisation
Direct chlorination (FeCl3) C2H4 + Cl2 C2H4Cl2
Cracking of 1,2-dichloroethane (EDC) C2H4Cl2 CH2=CHCl+ HCl
Poly Vinyl-Chloride (PVC)
Oxychlorination reaction (CuCl2) @ 230ºC C2H4 + 2HCl + ½ O2 C2H4Cl2 + H2O
PVC industry is growing market with recycling efforts
The basic commercial catalyst is CuCl2/ γ-Al2O3
Oxychlorination Catalyst – State of Art
Catalyst bed
HCl
C2H4
N2
Air
C2H4Cl2
C2H3Cl
C2H5Cl2
C2H3Cl3
CO2
Desired Product
300 ºC
Fixed bed reactor
X
Reaction mechanism
Promotes EDC
degradation
Promotes
ethylene burn
Promotes over-
chlorination
2 CuCl2 Cu2OCl2
2 CuCl
C2H4
C2H4Cl2 ½ O2
2 HCl H2O
Hydrochlorolysis
Chlorinated
By-products
Acid sites CuCl responsible for Cu-migration
CuCl2 responsible for particle agglomeration
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)
Our aim is very ambitious and can be summarized in the
following four main points:
Doped catalyst
Reactants
1) Influence on Surface and its properties Dispersion, active phase modifictaion, acidity of the surface….
2) Influence on reaction mechanism
and kinetics
3) Influence on thermal & mechanical
stability of the catalyst during reaction
4) Influence on Selectivity
Objective
Reactants
Kinetic tests
Activ
ity &
Se
lec
tivity
Doped Catalyst
In-situ mode or Operando
mode
Influence of Additivies Characterisation using combined spectroscopy
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)
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
2200 2150 2100
0.2 a.u.
Al2O
3
2183
2154
ab
sorb
an
ce u
nit
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
2158Cl2.8
A
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
0.5 a.u.
Li0.5
Cu5.0
2158
2128
no
rmal
ised
Ab
sorb
ance
(a.
u.)
0.5 a.u.
K3.1
Cu5.0
2123
2157
2118
Cs10.4
Cu5.0
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
kkRseneeR
kANSk ss
k
R
s s
ss s
s
22 222
2
2
2
0
1 2 3
img
(FT
)
R (Ao)
|FT
|
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 1.4 Cu 1.4
Cu 5.0
Cu 1.4
Cu 5.0
La10.9Cu 5.0
Li0.5Cu 5.0
Mg1.9Cu5.0
K3.1Cu5.0
Cs10.4Cu5.0
Cu-O
Cu-Cl
La>Li>Mg>K>Cs>Cu
All dopants are competing with Cu to occupy alumina octahedral vacancy sites
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 > La10.9Cu5.0 > Li 0.5Cu5.0 > Mg1.9Cu5.0 > K3.1Cu5.0 ≈ Cs10.4Cu5.0
N. B. Muddada et al., J.Catal (2011) accepted
230°C 270°C 300°C 350°C
0,0
0,1
0,2
re
lati
ve a
mo
un
t o
f b
y-p
rod
uct
s /
ED
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”
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/-Al2O3.
Acidity
% Cu(II) Dopant
Cu(II)/Cu(I)
Activity &
Selectivity
Acknowledgments
University of Torino
Prof. Carlo Lamberti Prof. Silvia Bordiga Dr. Elena Groppo Diego Gianolio
Prof. Adriano Zecchina Lab Colleagues
University of Bologna
Prof. Fabrazio Cavani Prof. L.Caccialupi
University of Oslo
Prof. Unni Olsbye Sharmala Arvindthan
INEOS (Norway & Italy) Terje Fuglerud
Andrea Marsella Sandra Vidotto
Consultant Giuseppe Leofanti
Thanks for your Attention…….
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 Al7Ox, Perovskite materials, Zeolites type materials.
UIO-66: Commerically available Zr- MOF
In-situ EXAFS+MS set-up
CuCl2 was loaded during synthesis of Zr-MOF ( uio-66)
SNBL - ESRF
-- @RT
-- @RT-200 C
-- @200C
-- @rxmx_200C
-- @rxmx_200C
-- cooling down
-- cooling down Cu+
Cu2+
CuCl2-Zr-MOF as redox catalyst - XANES
Ethylene+HCl+Air Mass Spec Conversion is
very very low!!!
Cu wt% ≈ 1,2 %
CuCl
CuCl2
Cu-MOF is showing red-ox proporties…
CuMOF : CuCl2 loaded onto Zr-MOF
CuMOF_RT_2
Operations: Import
CuMOF_rxmx_160C_2 - File: NBM_CuMof_rxmx_160C_2.raw - Type: 2Th/Th locked - Start: 3.000 ° - End: 40.004 ° - Step: 0.015 ° - Step time: 1. s - Temp.: 25 °C (Room) - Time Started: 11 s - 2-Theta: 3.000 ° - The
Operations: Import
CuMOF_rampup to 160C - File: NBM_CuMof_rampto_160C.raw - Type: 2Th/Th locked - Start: 3.000 ° - End: 40.004 ° - Step: 0.015 ° - Step time: 1. s - Temp.: 25 °C (Room) - Time Started: 11 s - 2-Theta: 3.000 ° - T
Operations: Import
CuMOF_RT_2 - File: NBM_CuMof_RT2.raw - Type: 2Th/Th locked - Start: 3.000 ° - End: 40.004 ° - Step: 0.015 ° - Step time: 1. s - Temp.: 25 °C (Room) - Time Started: 8 s - 2-Theta: 3.000 ° - Theta: 1.500 ° - Chi: 0.
Lin
(C
ou
nts
)
0
100
200
300
400
500
600
700
800
900
1000
1100
1200
1300
1400
1500
1600
1700
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1900
2000
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2200
2300
2400
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2-Theta - Scale
3 10 20 30 40
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
CuMOF_RT
Operations: Import
CuMOF_HCl gas@180C - File: [email protected] - Type: 2Th/Th locked - Start: 3.000 ° - En
Operations: Import
CuMOF_HCl gas@120C - File: [email protected] - Type: 2Th/Th locked - Start: 3.000 ° - En
Operations: Import
CuMOF_HCl gas@100C - File: [email protected] - Type: 2Th/Th locked - Start: 3.000 ° - En
Operations: Import
CuMOF_HCl gas@RT - File: [email protected] - Type: 2Th/Th locked - Start: 3.000 ° - End: 40
Operations: Import
CuMOF_RT - File: NBM_CuMof_RT1.raw - Type: 2Th/Th locked - Start: 3.000 ° - End: 40.004 ° - Step: 0
Lin
(C
ou
nts
)
0
1000
2000
3000
2-Theta - Scale
3 10 20 30 40
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