Selective removal of oxygen by carbon monoxide instead of hydrogen Maria Eugenia Sad Post-doctoral fellow Enrique Iglesia Principal Researcher Department of Chemical Engineering University of California at Berkeley Financial Support: BP January 14th 2009

Selective removal of O by C instead of H We propose novel strategies for the removal of oxygen from biomass derived Some of these proposed strategies are: in-situ formation of H2 or hydrogen-rich transfer species from H2O/CO Use of CO to extract oxygen from H2O with H2 as the desired by-product (water-gas shift reaction). direct use of CO to remove oxygen from biomass-derived oxygenates use of C atoms within these molecules (instead of their H atoms) to remove excess oxygen while preserving hydrogen We will first study simple molecules such as 1,3 propanediol and then will extend this knowledge to selective removal of O-atoms from more complex oxygenates such as glycerol, glucose, and coal-derived or biomass-derived

Fe-Zn oxides prepared by coprecipitation – Zn/Fe atomic ratio=0.1 Our catalysts Cu based catalysts CuO/ZnO/Al2O3 catalysts (CuO 52.5 %, ZnO 30.2%, Al2O3 17.0%) 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 Fe based catalysts Fe-Zn oxides prepared by coprecipitation – Zn/Fe atomic ratio=0.1 Fe is useful to carry out WGS reaction at high temperatures. Chromium oxide or zinc oxide are generally used as structural stabilizers and promoters Pt based catalysts 1% wt Pt/SiO2 prepared by incipient wetness impregnation 1.5% wt Pt/Al2O3 prepared by incipient wetness impregnation Precious metal-based catalysts are also used for WGS and they catalyze hydrogenation reaction too.

REACTION NETWORK -H2 -H2 -H2 +H2 -CO -H2O -H2O +H2 -H2 +H2 +H2 -H2O C2H6O ethanol C3H8O2 1,3 PD C3H6O2 3-hydroxy propanal C3H4O2 propanedial C2H4O acetaldehyde -H2O + 1,3 PD CH3 O CH3 O O CH2CH3 O -H2O C2H4 ethene 1,3 dioxane 2-methyl 1,3 dioxane 2-ethyl 1,3 dioxane +H2 + 1,3 PD OH O H C3H6O allyl alcohol C3H4O acrolein propionaldehyde C3H8O propanol C2H6 ethane -H2 +H2 +H2 O C6H14O dipropylether -H2O -H2O +H2 C3H6 propene C3H8 propane Metal catalysts Acid catalysts C3H4 allene

1,3 propanediol and He propionaldehyde CuZnAl2O3 catalyst 1 1,3 propanediol and He propionaldehyde 2 Hydrogenation of 1,3 propanediol using H2 OH C3H8O2 1,3 PD O H C3H6O propionaldehyde C3H8O propanol -H2O +H2 Conversion Propanol Propionaldehyde 10 kPa H2 20 kPa H2 40 kPa H2 3 In situ H2 formation (WGS reaction) and 1,3 PD 4 Effect of CO on 1,3 PD hydrogenation

Propanol/Propionaldehyde CuZnAl2O3 catalyst Hydrogenation of 1,3 propanediol X=100%, main products were propanol and propionaldehyde. PH2 [kPa] Propanol/Propionaldehyde [0.8 kPa 1,3 propanediol, 230ºC, 60 g h/mol, 50 mg cat] OH C3H8O2 1,3 PD O H C3H6O propionaldehyde C3H8O propanol -H2O +H2 OH O H In situ generation of H2 by WGS using 150 mg of catalyst XCO=75 % In situ generation of H2 by WGS 8 kPa CO, 21.3 kPa H2O X=100%, there was no enough H2 to form more propanol. 0.5 kPa

Does CO inhibit the use of H2 formed to hydrogenate our compounds??? Experiences co-feeding CO and H2 OH C3H8O propanol C3H6 propene C3H8 propane -H2O +H2 PH2 [kPa] Propanol/Propionaldehyde Propane/Propanol [0.8 kPa 1,3 propanediol, 230ºC, 60 g h/mol, 50 mg cat] OH O H 18 kPa CO 6 kPa CO 6, 18 or 50 kPa CO 90 kPa CO [230 ºC, 60 g h/mol, 10 kPa CO, 0.1 kPa 1,3 propanediol] 5 Dipropylether 6 Acrolein 7 Acetaldehyde 4 Propanol 78 Propionaldehyde Selectivity (%) Product CO does not react with 1,3 propanediol to form significantly amounts of propanol or propane… What happened if we only feed CO + 1,3 propanediol? 100 % conversion OH Moderate amounts of CO do not inhibit the use of H2 to form propanol and promote propane formation

10 kPa CO, 0.1 kPa 1,3 propanediol] Propane was formed from 1,3 propanediol when there was 80 kPa water and 8 kPa CO … 1,3 propanediol (0.8 kPa), CO (8 kPa), H2O (80 kPa) X=100%, Propane is formed at low time on stream (Spropane =35% at t=0). The main product was propionaldehyde Propane Propionaldehyde Propanol Conversion Excess of water favors WGS reaction CO favors propane formation Propane selectivity decreases with time on stream [230 ºC, 60 g h/mol, 10 kPa CO, 0.1 kPa 1,3 propanediol]

Hydrogenation of propionaldehyde on CuZnAl2O3 Until now we could successfully remove one O from 1,3 propanediol but we can not significantly form propane by eliminating the two O. When we tried to remove O from 1,3 propanediol using CO + H2O on Cu-based catalysts, the main product was propionaldehyde so… …we are going to study the hydrogenation of propionaldehyde [230ºC, 72.6 gr h/mol 0.64 kPa propionaldehyde, 10 kPa H2] When CO is co-feed, propane is formed 6 kPa CO Spropane=7% 18 kPa CO Spropane=15% no CO 6 KPa CO 18 KPa CO Propanol Conversion Propane Diprophylether But the main product is always propanol

Hydrogenation of propionaldehyde on CuZnAl2O3 plus more alumina Due to hydrogenation of propionaldehyde forms propanol as main product and not propane, we decided to use a mixture of CuZnAl2O3 (10 mg) and alumina (40 mg) to favor the dehydration reactions. Influence of CO in propionaldehyde hydrogenation Propanol Propane Conversion CO favors propane formation, specially at low time on stream Propanol Propane Conversion [230 ºC, 14.5 g h/mol, 18 kPa CO 0.64 kPa Propionaldehyde, 10 kPa H2] X = 53%, Spropanol= 93% [230 ºC, 14.5 g h/mol, 0.64 KPa Propionaldehyde, 10 kPa H2]

SUMMARY FOR Cu BASED CATALYSTS 1 CuZnAl catalysts favor the dehydration of 1,3 propanediol to form propionaldehyde in presence of H2 or CO + H2O. When H2 is fed the main product was propanol. However, the amount of H2 formed by WGS reaction is not enough to convert propionaldehyde into propanol. 2 80 kPa H2O and 8 kPa CO promote propane formation at low times on stream (Spropane =35% for t=0, X=100%). 3 When hydrogenation of propionaldehyde is carried out in presence of CO, propane is formed. OH C3H8O2 1,3 PD C3H6 propene C3H8 propane -H2O +H2 O H C3H6O allyl alcohol C3H4O acrolein propionaldehyde C3H8O propanol -H2

Fe-Zn oxide catalyst 1 Only 1,3 PD 2 Hydrogenation of 1,3 PD 3 0.8 kPa 1,3 propanediol [300ºC, 30 g h/mol] X Acrolein Propanol Propane Others 25 60 30 10 0.8 kPa 1,3 propanediol + 10 to 40 kPa H2 [300ºC, 30 g h/mol] 40 50 0.8 kPa 1,3 propanediol + 8 kPa CO + 21.3 kPa H2O [300ºC, 30 g h/mol] 67 23 0.8 kPa 1,3 propanediol + 8 kPa CO + 80 kPa H2O [300ºC, 60 g h/mol] 35 (20) 35 (55) 18 (14) 35 (15) 12 (16) Only 1,3 PD 2 Hydrogenation of 1,3 PD 3 1,3 PD + CO + H2O 4 1,3 PD + CO + H2O

SUMMARY Fe-Zn OXIDE CATALYSTS FeZn catalyst favors acrolein formation from 1,3 propanediol and its subsequent hydrogenation to propanol. The presence of both CO and H2 promote propane formation OH C3H8O2 1,3 PD C3H6 propene C3H8 propane -H2O +H2 O H C3H6O allyl alcohol C3H4O acrolein propionaldehyde C3H8O propanol -H2

1 wt% Pt/SiO2 Hydrogenation 1,3 propanediol (10 and 20 kPa H2) – [250 ºC, 60 g h/mol] X Ethene Ethane CO Propene Propane Propanol Propionald. Others 98 8 15 13 1 36 19 Hydrogenation 1,3 propanediol (10 and 20 kPa H2) – [300 ºC, 60 g h/mol] 100 10 26 25 2 0.5 28 6 2.5 1,3 propanediol + He – [250 ºC, 60 g h/mol] Ethane= Propane Allyl alcohol Propionaldehyde Acrolein 83 1.5 9 21 3 61 OH O H H O OH OH O H 1,3 propanediol reacts on Pt/SiO2 to form acrolein and propanol. Hydrogenation of 1,3 propanediol forms propanol and ethane as main products. Propane was not formed…so we used alumina as support to favor propanol to propene conversion…

1,3 propanediol + He – [250 ºC, 60 g h/mol] 1.5 wt% Pt/Al2O3 1,3 propanediol hydrogenation (10 and 20 KPa H2) – [250 ºC, 60 g h/mol] X Ethene Ethane CO Propene Propane Propanol Propionald. Acrolein 99 4 32 27 10 5 1 1,3 propanediol + He – [250 ºC, 60 g h/mol] 61 40 6 28 8 2 1,3 propanediol (0.8 kPa) + CO (8 kPa) + H2O (21 kPa) – [250 ºC, 60 g h/mol] CO2 35 22 0.5 3.5 11.5 13 34 O H H O OH Acrolein and ethene were the main products

1.5 wt% Pt/Al2O3 Acrolein Acrolein [250 ºC, 20 g h/mol, 0.64 kPa 1,3 PD, 8 kPa CO, 80 kPa H2O] Conversion Selectivity Acrolein H O Acrolein H O Conversion Propane Propane Ethene Ethene Propane is formed at low time on stream Acrolein Acetaldehyde CO2 Ethene Ally alcohol Propionaldehyde Propanol Propene Propane Ethane Primary products Secondary products

SUMMARY FOR Pt BASED CATALYSTS OH O H O H -H2 -H2 -H2 O H O H +H2 OH OH -CO C2H6O ethanol C3H8O2 1,3 PD C3H6O2 3-hydroxy propanal C3H4O2 propanedial C2H4O acetaldehyde -H2O -H2O OH O H C3H6O allyl alcohol C3H4O acrolein propionaldehyde C3H8O propanol C2H4 ethene -H2 +H2 +H2 +H2 C2H6 ethane -H2O In contrast with the Cu and Fe based catalysts, Pt favors ethene/ethane formation acrolein and propanol are also formed in presence of CO and water The presence of both CO and H2 promote propane formation +H2 C3H6 propene C3H8 propane

CONCLUSIONS AND FUTURE WORK We can successfully convert 1,3 PD into propionaldehyde using CuZnAl catalysts or into acrolein using FeZn or Pt catalysts. At this point we are able to remove one O from 1,3 PD. So, the next step is to find a catalyst that transforms propionaldehyde or acrolein into propene or propane. Our results showed that propane formation from 1,3 propanediol or propionaldehyde, is favored by using a H2/CO co-feed mixture, however, feeding only H2 does no produce propane. We are going to carry out more catalytic tests to try to understand this particular behavior.

Thank you very much for your attention!