Glycerol conversion to 1,2-propanediol
in mild conditions
Els D’Hondt
COK, KULeuven, Belgium
Poitiers, March 13, 2008
Content
•
Introduction
– Use of 1,2-propanediol
– Results with better literature catalysts
– Bifunctional mechanism
•
New bifunctional catalyst
–
–
–
–
–
–
•
Reaction conditions & Results
Overall conversion results
Stability 1,2-propanediol
Hydrogenation of hydroxy acetone
Effect of gaseous products: CO2 and H2
Origin of acidity in bifunctional pathway
Reaction pathways with new bifunctional catalyst
– Extended scheme for the bifunctional mechanism
– Suggested reforming mechanism
•
Conclusions
Content
•
Introduction
– Use of 1,2-propanediol
– Results with better literature catalysts
– Bifunctional mechanism
•
New bifunctional catalyst
–
–
–
–
–
–
•
Reaction conditions & Results
Overall conversion results
Stability 1,2-propanediol
Hydrogenation of hydroxy acetone
Effect of gaseous products: CO2 and H2
Origin of acidity in bifunctional pathway
Reaction pathways with new bifunctional catalyst
– Extended scheme for the bifunctional mechanism
– Suggested reforming mechanism
•
Conclusions
Introduction:
Use of 1,2-propanediol
OH
OH
1,2-Propanediol = bulk intermediate
– direct use as moistering or softening agent, as anti-freeze,
solvent or conservative
– monomer for polyesters, polyurethanes and alkyd resins
– preparation of cyclic ethers and 1,3-dioxanes used in organic
synthesis as solvents or intermediates
Introduction: Results with better
literature heterogeneous catalysts
• One step processes
T (°C)
p H2 (bar)
Results
CuCr
Cu/ZnO
Raney Cu
CuZnO/Al2O3
270
180
240
270
200
80
30
100
Y = 85 %
S = 100 %, X = 19 %
Y = 57 %
Y = 84 %
CoCuMnMo + H3PO4
Ru/C
RuS/C
230
210
240
250
60
130
Y = 96 %
Y = 75 %
Y = 75 %
Catalyst
Reference
Adkins et al. , Journal of the American Chemical Society, 54: 1138-1145, (1932)
Gallezot et al. , Green Chemistry, 6: 359-361, (2004)
Montassier et al. , Heterogeneous Catalysis and Fine Chemicals: 165-170, (1988)
Casale et al. , US Patent 5 214 219, (1993)
Schuster et al. , US Patent 5 616 817, (1997)
Montassier et al. , Journal of Molecular Catalysis, 70 (1), 99-110, (1991)
Casale et al. , US patent 5 276 181, (1994)
Y = yield, S = selectivity, X = conversion
• Multiple step processes
– Three step proces [1]
•
γ-Al2O3 at 300 °C + acid resin + Ni/Al 2O3/SiO2 at 140 °C and 40 bar H 2
Y = 60 %
– Two step proces [2]
• CuCr at 220 °C + CuCr at 300 °C and 14 bar H
Y = 62 %
2
[1] Haas, T., Neher, A., Arntz, D., Klenk, H. & Girke, W., US 5 426 249, (1995), [2] Suppes, G.J., Sutterlin, W.R. & Dasari, A., WO 2005/095536 A2, (2005)
Introduction:
Bifunctional mechanism
Glycerol conversion scheme via dual function catalyst *
OH
HO
1
OH
acid
1
O
OH
dehydration
glycerol
hydroxy acetone
OH
+ H2
OH
hydrogenation
1,2-propanediol
2
acid
dehydration
O
or
O
propanal
acetone
hydrogenation
+ H2
2
3
propane
3 acid
+ H2
hydrogenation
propene
dehydration
OH
OH
n-propanol
or
iso-propanol
* Suppes, G.J., Dasari, A.D., Kiatsimkul P. & Sutterlin, W.R., Applied Catalysis A: General, 281: 225-231 (2005).
Content
•
Introduction
– Use of 1,2-propanediol
– Results with better literature catalysts
– Bifunctional mechanism
•
New bifunctional catalyst
–
–
–
–
–
–
•
Reaction conditions & Results
Overall conversion results
Stability 1,2-propanediol
Hydrogenation of hydroxy acetone
Effect of gaseous products: CO2 and H2
Origin of acidity in bifunctional pathway
Reaction pathways with new bifunctional catalyst
– Extended scheme for the bifunctional mechanism
– Suggested reforming mechanism
•
Conclusions
New bifunctional catalyst:
Reaction conditions & Results
8
OH
HO
+ 3 H2O
new catalyst
+ 3 CO2
OH
OH
glycerol
OH
7
1,2-propanediol
• Mild conditions, no additives, heterogeneous catalyst,
inert atmosphere
–
–
–
–
100 ml batch reactor
230 °C, 15 h
40 ml 20 wt% glycerol in H2O
4 wt% catalyst
in situ H2 production
S 1,2-propanediol =
64 %
X glycerol =
85 %
Y 1,2-propanediol =
55 %
MB liquid C =
89 %
S = selectivity, X = conversion, Y = yield, MB = carbon mass balance of liquid products
New bifunctional catalyst:
Overall conversion results
100
X, S PDO, mb (%) .
Ssideproducts (%)
20
15
± Plateau S
X
S1,2-propanediol
mb
80
60
40
20
0
0
5
10
15
20 t (h) 25
10
Product
methanol
ethanol
acetone + propanal
iso-propanol
n-propanol
ethylene glycol
hydroxy-acetone
1,2-propanediol
conversion (%)
carbon mass balance of
liquid products (%)
Carbon
Selectivity (%)
0,9
9,5
1,0
1,4
7,5
2,1
3,0
64,0
85,4
Yield (%)
2,4
12,2
0,9
1,2
6,4
2,6
2,6
54,6
89,4
100 ml batch reactor, 230 °C, 15 h, 40 ml 20 wt% gl ycerol
in H2O, 4 wt% catalyst, Yield based on mol/L
5
SEtOH
S n-propOL
Selectivities and
MB liquid products rather
S OH-AcON
0
0
5
10
15
20
t (h)
100 ml batch reactor, 230 °C, 24 h, 40 ml 20 wt% gl ycerol in H2O, 4 wt% catalyst,
X = conversion, S = selectivity, mb = mass balance of liquid products, EtOH = ethanol,
n-propOL = n-propanol, OH-AcON = hydroxy acetone
25
constant
after initial period
New bifunctional catalyst:
Stability of 1,2-propanediol
Carbon
Selectivity (%)
conversion, Sside products (%)
25
Product
20
ethanol
acetone + propanal
iso-propanol
n-propanol
hydroxy-acetone
conversion (%)
carbon mass balance of
liquid products (%)
15
Sethanol
Sn-propanol
Shydroxy acetone
conversion
10
5
0
0
•
10
15
20
t (h) 25
70,7
Via bifunctional pathway to n-propanol
OH
H+
O
redox
OH
+ H2
- H2O
OH
•
5
40,5
1,3
5,7
18,6
4,7
24,7
Via dehydrogenation and cracking to ethanol and CO
OH
OH
OH
redox
- H2
O
OH
O
redox
OH + CO
100 ml batch reactor, 230 °C, 24 h, 40 ml 20 wt% 1, 2-propanediol in H2O, 4 wt% catalyst, S = carbon selectivity
New bifunctional catalyst:
Hydrogenation of hydroxy acetone
Product
methanol
ethanol
acetone + propanal
iso-propanol
n-propanol
ethylene glycol
1,2-propanediol
conversion (%)
carbon mass balance of
liquid products (%)
Carbon Selectivity (%)
no H2
42 bar H2
OH
O
0,0
5,0
2,6
0,3
2,0
0,0
65,6
77,9
0,0
1,4
0,4
1,0
1,8
0,0
91,3
98,7
75,4
95,9
redox
OH
•
Equimolar amount of H2
and hydroxy acetone
– Fast hydrogenation
– Low selectivity for CO, CO2 and CH4
– Enhanced selectivity for propane
OH + CO
O
Fast hydrogenation
or
cracking into ethanol and CO
OH
O
OH
OH
H+
- H2O
redox
or
O
+ H2
or
H+
OH - H2O
100 ml batch reactor, 230 °C, 1 h, 40 ml 20 wt% hyd roxy acetone in H2O, 4 wt% catalyst
redox
+ H2
New bifunctional catalyst:
Effect of gaseous products
Product
methanol
ethanol
acetone + propanal
iso-propanol
n-propanol
ethylene glycol
hydroxy-acetone
1,2-propanediol
conversion (%)
carbon mass balance of
liquid products (%)
no H2
24 h
0,9
10,6
0,9
1,9
8,9
1,0
2,0
45,8
100,0
72,0
Carbon Selectivity (%)
5 bar CO2 20 bar CO2 5 bar H2
24 h
24 h
24 h
0,8
0,7
0,9
12,2
12,3
9,6
1,0
2,2
0,5
1,9
0,0
1,3
8,2
10,5
7,1
0,8
0,4
2,0
2,4
2,4
2,0
43,7
34,4
50,7
99,7
99,2
96,3
71,0
62,9
100 ml batch reactor, 230 °C, 24 or 72 h, 40 ml 20 w t% glycerol in H2O, 4 wt% catalyst
74,0
42 bar H2
72 h
1,2
6,7
0,2
1,4
8,0
2,0
1,0
76,8
100,0
97,4
New bifunctional catalyst:
Effect of gaseous products
Product
methanol
ethanol
acetone + propanal
iso-propanol
n-propanol
ethylene glycol
hydroxy-acetone
1,2-propanediol
conversion (%)
carbon mass balance of
liquid products (%)
•
no H2
24 h
0,9
10,6
0,9
1,9
8,9
1,0
2,0
45,8
100,0
72,0
Carbon Selectivity (%)
5 bar CO2 20 bar CO2 5 bar H2
24 h
24 h
24 h
0,8
0,7
0,9
12,2
12,3
9,6
1,0
2,2
0,5
1,9
0,0
1,3
8,2
10,5
7,1
0,8
0,4
2,0
2,4
2,4
2,0
43,7
34,4
50,7
99,7
99,2
96,3
71,0
Equimolar amount of H2 and glycerol
– Decreased activity
72 h for full conversion
62,9
74,0
42 bar H2
72 h
1,2
6,7
0,2
1,4
8,0
2,0
1,0
76,8
100,0
97,4
Inhibition
reforming
Increased S 1,2-propanediol 77 %
Increased MB liquid C
97 %
100 ml batch reactor, 230 °C, 72 h, 40 ml 20 wt% gl ycerol in H2O, 4 wt% catalyst, S = selectivity, MB = carbon mass balance of liquid products
New bifunctional catalyst:
Effect of gaseous products
Product
methanol
ethanol
acetone + propanal
iso-propanol
n-propanol
ethylene glycol
hydroxy-acetone
1,2-propanediol
conversion (%)
carbon mass balance of
liquid products (%)
no H2
24 h
0,9
10,6
0,9
1,9
8,9
1,0
2,0
45,8
100,0
72,0
•
5 bar CO2: No effect
•
20 bar CO2: Increased activity
Carbon Selectivity (%)
5 bar CO2 20 bar CO2 5 bar H2
24 h
24 h
24 h
0,8
0,7
0,9
12,2
12,3
9,6
1,0
2,2
0,5
1,9
0,0
1,3
8,2
10,5
7,1
0,8
0,4
2,0
2,4
2,4
2,0
43,7
34,4
50,7
99,7
99,2
96,3
71,0
62,9
– Decreased 1,2-propanediol selectivity
– Decreased carbon mass balance liquid products
100 ml batch reactor, 230 °C, 24 h, 40 ml 20 wt% gl ycerol in H2O, 4 wt% catalyst
74,0
42 bar H2
72 h
1,2
6,7
0,2
1,4
8,0
2,0
1,0
76,8
100,0
97,4
Consecutive
reactions
CO2 + H2O H2CO3
Origin of acidity in bifunctional
mechanism
20 bar CO2 as acid catalyst, no catalyst
– Hydroxy acetone is formed in presence of 20 bar CO2
– Versus thermostability of glycerol (X = 0 %) without
catalyst
50
X, S ethanol, Shyroxy acetone (%)
•
Sethanol
Shydroxy acetone
X
40
30
20
10
0
0
Only the metal as catalyst, no carrier
2
3
4
5
6
7 t (h) 8
100 ml batch reactor, 230 °C, 7 h, 40 ml 20 wt% gly cerol
in H2O, 20 bars CO2 , X = conversion, S = selectivity
100
45
Sn-propOL no carrier
Sn-propOL
40
80
Sside products (%)
– Low conversion
– Higher S side products
– High MB liquids
X, S, Y, mb (%)
•
1
60
40
20
SOH-AcON no carrier
SOH-AcON
35
30
25
20
15
10
5
CO2 as
acid catalyst
0
0
5
X no carrier
X
10
15
SPDO no carrier
SPDO
t (h) 25
20
mb no carrier
mb
0
0
5
10
15
20
t (h) 25
100 ml batch reactor, 230 °C, 24 h, 40 ml 20 wt% gl ycerol in H2O, 0,26 mmol metal (…) or patented catalyst (―),
X = conversion, S = selectivity, Y = yield, mb = carbon mass balance of liquid products, PDO = 1,2-propanediol,
n-propOL = n-propanol, OH-AcON = hydroxy acetone
Content
•
Introduction
– Use of 1,2-propanediol
– Results with better literature catalysts
– Bifunctional mechanism
•
New bifunctional catalyst
–
–
–
–
–
–
•
Reaction conditions & Results
Overall conversion results
Stability 1,2-propanediol
Hydrogenation of hydroxy acetone
Effect of gaseous products: CO2 and H2
Origin of acidity in bifunctional pathway
Reaction pathways with new bifunctional catalyst
– Extended scheme for the bifunctional mechanism
– Suggested reforming mechanism
•
Conclusions
Bifunctional mechanism:
Extended scheme
OH
HO
acid
isomerisation
O
OH
dehydration
glycerol
OH
OH
hydroxy acetone
O
2-hydroxy propanal
1
1
hydrogenation
C-CO cracking
OH
OH
OH
1,2-propanediol
2 acid
+ CO
ethanol
dehydration
acid
dehydration
O
O
propanal
propene
hydrogenation
3
3
acid
dehydration
acetone
2
hydrogenation
ethene
hydrogenation
OH
OH
propane
isomerisation
n-propanol
isomerisation
iso-propanol
ethane
Suggested reforming mechanism:
Based on experimental data
OH
HO
OH
glycerol
(de)hydrogenation
O
HO
H
+ CO + H2
redox
hydroxy ethanal
redox
O
OH
HO
O
glyceraldehyde
+ H2
H2 +
HO
dihydroxy acetone
(de)hydrogenation
O
H
H
+ CO + H2
OH
HO
ethylene glycol
formaldehyde
Equilibrated via
water gas shift reaction:
redox
(de)hydrogenation
OH
CO + H2
H
H
H
methanol
OH
CO + H2O CO2 + H2
Content
•
Introduction
– Use of 1,2-propanediol
– Results with better literature catalysts
– Bifunctional mechanism
•
New bifunctional catalyst
–
–
–
–
–
–
•
Reaction conditions & Results
Overall conversion results
Stability 1,2-propanediol
Hydrogenation of hydroxy acetone
Effect of gaseous products: CO2 and H2
Origin of acidity in bifunctional pathway
Reaction pathways with new bifunctional catalyst
– Extended scheme for the bifunctional mechanism
– Suggested reforming mechanism
•
Conclusions
Conclusions
•
Characteristics of the proces
– in situ H2 production: reforming + water gas shift reaction
Inhibition reforming by biogenic H2 pressure
C3H8O3 3 CO + 4 H2
8 C3H8O3 + 3 H2O 7 C3H8O2 + 3 CO2
X glycerol = 85 %
•
S 1,2-propanediol = 64 %
MB liquid C = 89 %
3 CO + 3 H2O 3 CO2 + 3 H2
7 C3H8O3 + 7 H2 7 C3H8O2
Specific carrier
– Good stability of 1,2-propanediol
Affinity glycerol > affinity 1,2-propanediol
– Fine tuned acidity
Minor consecutive reactions
– Quenching carbon acid acidity
– Isomerisation
Provides more substrates for reforming
Thank you
for your attention!