CO + H 2. hydrocarbons oxygenates

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1 C + 2 hydrocarbons oxygenates Why? ydrocarbons and oxygenates as fuels and chemicals. Conversion of synthesis gas from diverse carbon sources (biomass, coal, natural gas, tar sands, ) Known chemistries, yet unanswered mechanistic questions in C hydrogenation.

2 Iglesia, E. et al., Advances in Catalysis, 39 (1993) 221

3 α-lefin readsorption and growth Paraffins are terminal products Iglesia, E. et al., Advances in Catalysis, 39 (1993) 221

4 α-lefin readsorption and growth Paraffins are terminal products Iglesia, E. et al., Advances in Catalysis, 39 (1993) 221

5 β C4 =1.1 α-lefin readsorption and growth Paraffins are terminal products Iglesia, E. et al., Advances in Catalysis, 39 (1993) 221

6 β C4 =1.1 α-lefin readsorption and growth C 4 C 1 * C 2 * Investigating the behavior of the C 1 surface species Paraffins are terminal products Iglesia, E. et al., Advances in Catalysis, 39 (1993) 221

7 Challenges in Forming the First C-C Bond During Synthesis Gas Conversion 2 / C C 3 C 2 5 C 3 7 C n+1 2n+3 C x C x Co, Co-M Rh, Rh-X MoS x -K C 1 * C 2 * C n * C 4 C 2 4 C 2 6 C n 2n C n 2n+2 ne of the challenges is the first C-C bond formation

8 Challenges in Forming the First C-C Bond During Synthesis Gas Conversion 2 / C C 3 C 2 5 C 3 7 C n+1 2n+3 C x C x Co, Co-M Rh, Rh-X MoS x -K C 1 * C 2 * C n * C 4 C 2 4 C 2 6 C n 2n C n 2n+2 ne of the challenges is the first C-C bond formation Why do we make so much C 4? ow can we investigate the initial C-C bond formation? Isotopically labeled compounds ( 13 C, 13 C 3 ) to track the carbon. ther questions What is the monomer for hydrocarbon/ oxygenate formation? ow does it form? Why does C 8 1 * either propagate slowly or terminate quickly?

9 C 2 C

10 C 2 -assisted Dissociation C* + * C* C C C Unassisted Dissociation C* C* + * C C

11 C 2 -assisted Dissociation C* + * C* C C C Unassisted Dissociation C* C* + * C C Favored energetically (1) Un-favored Isotopically labeled compounds ( 13 C, 13 C 3 ) to track the carbon. (1) - jeda, M., Nabar, R., Nilekar, A. U., Ishikawa, A., Mavrikakis, M., Iglesia, E., Unpublished Results.

12 C 2 C Krishnamoorthy, S., et al., J. Cat. 211, 422 (2002)

13 C 2 C Krishnamoorthy, S., et al., J. Cat. 211, 422 (2002) Bertole, C. J., et al., J. Cat. 210, 84 (2002) 2 increases the amount of active carbon for FTS

14 C 2 C Krishnamoorthy, S., et al., J. Cat. 211, 422 (2002) Does 2 activate C? 2 * + C* C* + * Bertole, C. J., et al., J. Cat. 210, 84 (2002) 2 increases the amount of active carbon for FTS

15 Isotopic and Kinetic Assessment of Chain Growth Processes 2 /C Gradient-less RRU micropump 20 bar C Catalyst GC/MS Sampling port GC Cold Trap eated Enclosure (150 C) Continuous on-line analysis of C 15- products Analogous to PFR, differential rates and selectivities at all conversion levels

16 The Curious Case of 2 Increased Rates, Changes in Selectivity Crossed symbols w/ 0.6 bar 2 Filled symbols - dry Dry Wet C conversion (%) Site =me yield (h 1 ) C 1 Selec=vity (C 2 free, %) C 5+ Selec=vity (C 2 free, %) C 3 /P Ra=o 1 2 Selec%vity, C 2 free, % C 5+ C C Conversion (%) 200 C, 16 bar initial, 2 /C=2, 15 mg 30 wt% Co/Si mg Si 2 C 1 C 2 C n C* ki θ C* k t1 θ C1* k tn θ C1* C 1 * C 2 * C n * k g θ C1* θ C* k g θ C2* θ C* k g θ Cn-1* θ C* k tn θ Cn* k g θ Cn* θ C*

17 FTS Extending and Alcohol FT Chemistry Synthesis to Alcohol Similar Chemistries, Synthesis Different Selectivities 2 / C C 3 C 2 5 C 3 7 C n+1 2n+3 C x C x Co, Co-M Rh, Rh-X MoS x -K C 1 * C 2 * C n * C 4 C 2 4 C 2 6 C n 2n C n 2n+2

18 FTS Extending and Alcohol FT Chemistry Synthesis to Alcohol Similar Chemistries, Synthesis Different Selectivities 2 / C C 3 C 2 5 C 3 7 C n+1 2n+3 C x C x Co, Co-M Rh, Rh-X MoS x -K C 1 * C 2 * C n * C 4 C 2 4 C 2 6 C n 2n C n 2n+2 C n 2n+2 alcohol C n-1 * C n * C n+1 * aldehyde C n 2n Which intermediates are common to both FTS and AS? Which catalyst is suitable for investigation? Primary/secondary products?

19 Rh-Mn/Si Extending 2 FT is a Chemistry Promising to Catalyst Alcohol for Synthesis AS At identical conditions Selectivity T P Cat. 2 /C GSV syn X C C 4 C 2 6 C 2 C 3 C 2 5 C 3 7 C 4 9 C bar mol/mol cm 3 (STP) h -1 g -1 cat % % % % % % % % Rh/Si n.a. 42 n.a n.a - - Rh-Mn/Si n.a n.a n.a - At similar C conversions Selectivity T P Cat. 2 /C GSV tot X C C 4 C 2 6 C 2 XY/C /P 2 /P 3 /P 4 C bar mol/mol cm 3 (STP) h-1 g -1 cat % % % % Rh/Si n.a Rh-Mn/Si n.a C 3 C 2 5 C 3 7 C n+1 2n+3 C 1 * C 2 * C n * C 4 C 2 4 C 2 6 C n 2n C n 2n+2

20 Moving Extending Towards FT Chemistry a Possible to Reaction Alcohol Mechanism Synthesis

21 Moving Extending Towards FT Chemistry a Possible to Reaction Alcohol Mechanism Synthesis

22 Extending Methanol FT Chemistry Effects and to Alcohol Future Work Synthesis Co-fed Me led to Disappearance of acetic acid & concurrent increase in methyl acetate selectivity Increase in ethanol selectivity Disappearance of ethyl acetate Future Work includes Et, acetaldehyde, & acetic acid co-feeding Isotopic tests in RRU FTIR work to interrogate surface populations

23 Current/Future Work and Acknowledgements Acknowledgments Isotopic experiments with isotopically-labeled compounds Investigation of the effect of water in synthesis gas conversion Experiments on higher alcohol synthesis (Rh, Rh-X) Carlo Visconti, Visiting Professor, Politecnico di Milano 2 /C micropump 20 bar Acknowledgments - Enrique Iglesia C Catalyst GC/MS - BP - Carlo Visconti Sampling port GC - LSAC Cold Trap eated Enclosure (150 C)