1. Selective removal of oxygen from biomass-derived compounds
Maria Eugenia Sad
Post-doctoral fellow
Enrique Iglesia
Principal Researcher
Department of Chemical Engineering
University of California at Berkeley
Financial Support: BP
June 30th 2009

2. Alternatives to remove O from biomass-derived compounds
Oxygen could be removed via:
intramolecular use of C-atoms, e.g. decarboxylation
intermolecular reactions with CO
use of CO to extract H from H2O via water gas shift as alternative to the on-purpose generation
WGS shift is the simplest manifestation of the selective removal of oxygen from the simplest oxygenate namely H2O.
-(CHx)- O* H*
“CHxOy”
CO/H2O CO
none
…. increase H/(C,O) ratio

3. Catalysts Cu based catalysts 1,3 propanediol reactions
Cu is a well-know catalyst used for WGS reaction at low temperatures. Zinc oxide is used as structural stabilizers and promoters. Aluminum oxide, although inactive for the WGS reaction, is added to improve the catalyst dispersion
Cu/SiO2 (incipient wetness impregnation)
Cu/C (incipient wetness impregnation)
CuO/ZnO/Al2O3 (commercial and prepared in the lab by co-precipitation)
1,3 propanediol reactions
Experiences using only 1,3 PPD and He on CuZnAl catalyst
X=100% , Spropanal=85 %
It is easy to transform 1,3 PPD to propanal/propanol on CuZnAl catalyst
Propanal and propanol are in equilibrium. We can consider them as a unique specie and the amount of propanol would be only function of the hydrogen concentration
Propane can be formed from propanol using CO to remove the O

4. 1,3 propanediol reactionsOH
C3H8O2
1,3 PPD
Reactions that do not required co-reactants OH
+H2
-H2O
Reaction that required H2
C3H8O
propanol
C3H6
propene
C3H8
propane
-H2O O H O H
Reaction that required CO
+CO
-CO2 OH
-H2
+H2
C3H6O
allyl alcohol
C3H4O
acrolein
C3H6O
propanal
keto-enol tautomerism

5. Experimental results using 1,3PPD
Reactions with 1,3 propanediol - CuZnAl-MS kPa 1,3 PPD – 230 C
10 kPa H2 OH O H OH O H
10 kPa H2 OH
Propanol and propanal are in equilibrium with or without H2.
Only H2 does not form propane.
Propane is formed from propanol when CO is present (Alkanol gas shift reaction). OH
C3H8O
propanol
C3H8
propane
+ CO
+ CO2

6. Reactions with 1,3 propanediol - CuZnAl-MS-02 - 0.8 kPa 1,3 PD – 230 C
Does CO inhibit the use of H2 formed to hydrogenate our compounds???
Reactions with 1,3 propanediol - CuZnAl-MS kPa 1,3 PD – 230 C OH O H OH O H OH
CO + HOH CO2 + H Water gas shift reaction
CO + ROH CO2 + RH Alkanol gas shift reaction OH
C3H8O
propanol
C3H6
propene
C3H8
propane
-H2O
+H2
+CO
-CO2
10 kPa H2
10 kPa H2
Presence of CO increases propanol/propanal ratio when 1,3 PD is fed.
Only H2 does not form propane.
Propane is formed from propanol when CO is present (Alcohol gas shift reaction). OH
C3H8O
propanol
C3H8
propane
+ CO
+ CO2

7. Propanol/propanal as reactant…
Propanol/propanal mixtures (0.64 kPa) + H2 (10, 50, 80 kPa) or without co-reactants on Cu based-catalysts form mainly C5 and C6 products.
We have to use higher amounts of catalysts.
When CO is present propane is also formed by Alkanol Gas Shift reaction

8. Propanol/propanal as reactant…
Alkanol gas shift vs water gas shift
Alkanol
Water
When CO is present propane is also formed by Alkanol Gas Shift reaction
R O H H O H
R ---- OH
R=O + H2
RO ---- H
H ---- OH HO ---- H
H OH
CO CO2
R OH RH
CO CO2 H2
In order to favor RH formation we need to find a catalyst suitable for breaking C-O bond preferentially Cu Fe Pt Pd Re Ru Ni Co Cu Fe Pt

9. Propanol/propanal as reactant…
Propanol/propanal mixtures (0.64 kPa) + H2 (10, 50, 80 kPa) or without co-reactants on Cu based-catalysts form mainly C5 and C6 products.
We have to use higher amounts of catalysts.
When CO is present propane is also formed by Alkanol Gas Shift reaction

10. Propanol/propanal as reactant…
Propanol/propanal mixtures (0.64 kPa) + H2 (10, 50, 80 kPa) or without co-reactants on Cu based-catalysts form mainly C5 and C6 products.

11. +H2 +H2 -H2O AGS -H2O Cα - CO - H2 - CO - H2 Cβ +H2 H2 -H2O C=O + O OH
propene
C3H8
propane
+H2
-H2O
AGS
3 pentanone
- H2
- CO O OH
2 methyl pentanal
2 methyl 3-pentanone
+H2
-H2O Cα OH
- H2
- CO O OH
+H2
-H2O
hexanal
3 hexanone Cβ
C3H8O
propanol H2 O H O
propylpropionate
propanol
propionic acid OH +
C=O
C3H6O
propanal

12. +H2 +H2 -H2O AGS +H2 -H2O -H2O Cα - CO - H2 - CO - H2 Cβ H2 +H2 -H2O
propene
+H2
-H2O
C3H8
propane OH O
2 methyl 3-pentanone
AGS O
+H2
-H2O O OH
-H2O
2 methyl pentanal Cα OH
- CO
- H2 O
- CO
C3H8O
propanol
- H2
3-pentanone Cβ H2 O OH
+H2
-H2O O O H
hexanal
+H2
-H2O
C3H6O
propanal OH O O
C=O
3 hexanone O OH O OH +
propylpropionate
propionic acid
propanol

13. +H2 -H2O Only when CO is present AGS +H2 -H2O Cα - CO - H2 H2
C3H8
propane
AGS
Only when CO is present O
+H2
-H2O OH O
2 methyl 3-pentanone O
+H2
-H2O O OH
2 methyl pentanal Cα OH
- CO
- H2 O
C3H8O
propanol
3-pentanone H2
Aldol products O H
C3H6O
propanal
Ester
C=O O OH O OH +
propylpropionate
propionic acid
propanol

14. Propanol/propanal reactions
Hydrogenation of propanol and effect of CO over conversion and selectivities
Catalyst
X [%]
Contact time [g h/mol]
Ester
Aldol products
Propane
0.64 kPa propanol + 10 kPa H2
10%Cu/SiO2 2
375 75 25
20%Cu/SiO2
10.4
300
43.5
49.4
Cu/ZnO/Al2O3
5.4
150 47 40
10%Cu/C
1.8 66 28
0.64 kPa propanol + 10 kPa H2 + CO
1.6
50-62
27-16
8.6
40-50
15-3
1.7-1
55-76
30-33
17-6
Hydrogenation of propanol over Cu based catalysts produces mainly condensation products (C5 and C6) and no propene/propane.
Usually, condensation reactions are carried out using base catalyst…
Here, we found that also metallic catalysts (Cu) can formed these compounds.

15. THANK YOU FOR YOUR ATTENTION!!!!
In progress…
We are trying to determine if there is a relationship between Cu superficial and catalytic activity for these condensation reactions.
We are studying the effect of H2 partial pressure on the propanol/propanal conversion and product distribution.
it seems that one o more products would inhibit some reactions…
THANK YOU FOR YOUR ATTENTION!!!!