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

1800

1900

2000

2100

2200

2300

2400

2500

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: NBM_CuMof_HCl@180C.raw - Type: 2Th/Th locked - Start: 3.000 ° - En

Operations: Import

CuMOF_HCl gas@120C - File: NBM_CuMof_HCl@120C.raw - Type: 2Th/Th locked - Start: 3.000 ° - En

Operations: Import

CuMOF_HCl gas@100C - File: NBM_CuMof_HCl@100C.raw - Type: 2Th/Th locked - Start: 3.000 ° - En

Operations: Import

CuMOF_HCl gas@RT - File: NBM_CuMof_HCl@RT.raw - 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