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

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

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

1,3 propanediol reactions OH 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

Experimental results using 1,3PPD Reactions with 1,3 propanediol - CuZnAl-MS-02 - 0.8 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

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-02 - 0.8 kPa 1,3 PD – 230 C OH O H OH O H OH CO + HOH CO2 + H2 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

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

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

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

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.

+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

+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

+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

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 14-18.2 27-16 8.6 37-43.4 40-50 15-3 5.2-3.2 36.6-44.5 34.9-40.2 24.7-6.8 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.

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!!!!