Role of products and intermediates in bioethanol conversion to hydrocarbons on H-ZSM-5: A time-resolved study

Role of products and intermediates in bioethanol conversion to hydrocarbons on H-ZSM-5: A time-resolved study Rakesh Batchu, Vladimir V. Galvita, Konstantinos Alexopoulos, Kristof Van der Borght, Hilde Poelman, Marie-Françoise Reyniers and Guy B. Marin Laboratory for Chemical Technology, Ghent University http://www.lct.ugent.be NAM25, Denver, 4-9 June, 2017 1

Outline Introduction Experimental technique Mechanistic insights Conclusions 2

2 nd Generation NAM25, Denver, 4-9 June, 2017 1 st Generation 3 rd Generation Introduction - Bioethanol Renewable source - Simple sugars - Lignocellulosic materials - Marine species 3

Introduction - Bioethanol Renewable source - Simple sugars - Lignocellulosic materials - Marine species Usage - Fuel and - Chemicals J.A. Posada et al. Bioresource Technology, 135 (2013) 490 499 3

Introduction - Bioethanol Renewable source - Simple sugars - Lignocellulosic materials - Marine species Usage - Fuel and - Chemicals Low green house gas emissions - Neat fuel Emission Facts; Greenhouse Gas Impacts of Expanded Renewable and Alternative Fuels Use (EPA420- F-07-035), in, National Service Center for Environmental Publications (NSCEP), 2007 3

Introduction - Mechanisms 4

Introduction - Mechanisms C 2 H 5 OH ZSM-5 C x H y 4

Introduction - Mechanisms Hydrocarbon pool C 2 H 5 OH ZSM-5 I.M. Dahl et al. Journal of Catalysis, 149 (1994) 458-464 C x H y 4

Introduction - Mechanisms Hydrocarbon pool C 2 H 5 OH ZSM-5 I.M. Dahl et al. Journal of Catalysis, 149 (1994) 458-464 C x H y U. Olsbye et al. Angewandte Chemie International Edition, 51 (2012) 5810-5831 4

Introduction - Mechanisms Hydrocarbon pool Radical mechanism C 2 H 5 OH ZSM-5 I.M. Dahl et al. Journal of Catalysis, 149 (1994) 458-464 C x H y F.F. Madeira et al. ACS Catalysis, 1 (2011) 417-424 U. Olsbye et al. Angewandte Chemie International Edition, 51 (2012) 5810-5831 4

Acid catalyzed Oligomerization Cracking - Aromatization Introduction - Mechanisms Hydrocarbon pool A.G. Gayubo et al. Industrial & Engineering Chemistry Research, 40 (2001) 3467-3474. Radical mechanism C 2 H 5 OH ZSM-5 I.M. Dahl et al. Journal of Catalysis, 149 (1994) 458-464 C x H y F.F. Madeira et al. ACS Catalysis, 1 (2011) 417-424 U. Olsbye et al. Angewandte Chemie International Edition, 51 (2012) 5810-5831 4

Acid catalyzed Oligomerization Cracking - Aromatization Introduction - Mechanisms Hydrocarbon pool A.G. Gayubo et al. Industrial & Engineering Chemistry Research, 40 (2001) 3467-3474. Radical mechanism C 2 H 5 OH ZSM-5 I.M. Dahl et al. Journal of Catalysis, 149 (1994) 458-464 C x H y F.F. Madeira et al. ACS Catalysis, 1 (2011) 417-424 TAP reactor - Products development - Role of products and intermediates U. Olsbye et al. Angewandte Chemie International Edition, 51 (2012) 5810-5831 4

Experimental technique 5

Experimental technique Capable of Pulse and Flow experiments. 5

Experimental technique Capable of Pulse and Flow experiments. Pulse experiments - Four pulse injectors - Low pulse intensities (10 13-16 molecules) & High vacuum ( 10-7 torr) - Milli-second resolution in data acquisition 5

Experimental technique Capable of Pulse and Flow experiments. Pulse experiments - Four pulse injectors - Low pulse intensities (10 13-16 molecules) & High vacuum ( 10-7 torr) - Milli-second resolution in data acquisition Thin-zone TAP reactor configuration 5

Experimental technique Capable of Pulse and Flow experiments. Pulse experiments - Four pulse injectors - Low pulse intensities (10 13-16 molecules) & High vacuum ( 10-7 torr) - Milli-second resolution in data acquisition Thin-zone TAP reactor configuration TAPFIT Transport and Kinetics 5

Experimental technique Single pulse experiment Reactant Size ~ 10 14-15 molecules Reactant Product Knudsen diffusion regime. No change in the state of the catalyst. t/s t/s 6

Experimental technique Single pulse experiment Reactant Size ~ 10 14-15 molecules Reactant Product Knudsen diffusion regime. No change in the state of the catalyst. Multi pulse experiment t/s Size > 10 16 molecules/pulse Molecular diffusion regime. Reactant Product t/s Deliberate change in the state of the catalyst. t/s t/s 6

Experimental technique Single pulse experiment Reactant Size ~ 10 14-15 molecules Reactant Product Knudsen diffusion regime. No change in the state of the catalyst. Multi pulse experiment t/s Size > 10 16 molecules/pulse Molecular diffusion regime. Reactant Product t/s Deliberate change in the state of the catalyst. Pump Probe experiment Reactant I Reactant II t t/s t/s Reactant I Reactant II CO Product 2 t/s t/s Two pulses of different gases. Varying time delay of the pulses, lifetime of active surface species can be determined. 6

Insights Ethanol vs Ethene Single-pulse experiments of ethanol over ZSM-5 at 623 K, 7

Single-pulse experiments of ethanol over ZSM-5 at 623 K, 80% conversion Only product - ethene No higher hydrocarbons Insights Ethanol vs Ethene n ethene, X 10-6 mol s -1 Ethene 30 Feed : Ethanol 15 0 0.25 0.50 0.75 1.00 t, s 7

Single-pulse experiments of ethanol over ZSM-5 at 623 K, 80% conversion Only product - ethene No higher hydrocarbons Incomplete ethanol conversions => no higher hydrocarbons => supported by DFT calculations. Insights Ethanol vs Ethene n ethene, X 10-6 mol s -1 30 15 0 Ethene Feed : Ethanol 0.25 0.50 0.75 1.00 t, s 7

Single-pulse experiments of ethanol over ZSM-5 at 623 K, 80% conversion Only product - ethene No higher hydrocarbons Incomplete ethanol conversions => no higher hydrocarbons => supported by DFT calculations. Single-pulse experiments of ethene and ethene + water mixture over ZSM-5 at 648 K, Higher hydrocarbon formation and Similar product distribution Insights Ethanol vs Ethene n ethene, X 10-6 mol s -1 n butene, X 10-8 mol s -1 30 15 0 6 4 2 0 Ethene Feed : Ethanol 0.25 0.50 0.75 1.00 t, s Butene (higher hydrocarbon) Feed : Ethene Feed : Ethene + Water 0.25 0.50 0.75 1.00 t, s 7

Single-pulse experiments of ethanol over ZSM-5 at 623 K, 80% conversion Only product - ethene No higher hydrocarbons Incomplete ethanol conversions => no higher hydrocarbons => supported by DFT calculations. Single-pulse experiments of ethene and ethene + water mixture over ZSM-5 at 648 K, Higher hydrocarbon formation and Similar product distribution Ethene => precursor to higher hydrocarbon formation Insights Ethanol vs Ethene n ethene, X 10-6 mol s -1 n butene, X 10-8 mol s -1 30 15 0 6 4 2 0 Ethene Feed : Ethanol 0.25 0.50 0.75 1.00 t, s Butene (higher hydrocarbon) Feed : Ethene Feed : Ethene + Water 0.25 0.50 0.75 1.00 t, s 7

Single-pulse experiments of ethanol over ZSM-5 at 623 K, 80% conversion Only product - ethene No higher hydrocarbons Incomplete ethanol conversions => no higher hydrocarbons => supported by DFT calculations. Single-pulse experiments of ethene and ethene + water mixture over ZSM-5 at 648 K, Higher hydrocarbon formation and Similar product distribution Ethene => precursor to higher hydrocarbon formation No effect of water Insights Ethanol vs Ethene n ethene, X 10-6 mol s -1 n butene, X 10-8 mol s -1 30 15 0 6 4 2 0 Ethene Feed : Ethanol 0.25 0.50 0.75 1.00 t, s Butene (higher hydrocarbon) Feed : Ethene Feed : Ethene + Water 0.25 0.50 0.75 1.00 t, s 7

Insights Induction time (Single pulse) Routes from initial stages of the reaction? K. Van der Borght, R. Batchu, V.V. Galvita, K. Alexopoulos, M.F. Reyniers, J.W. Thybaut, G.B. Marin, Angew Chem Int Ed Engl, 55 (2016) 12817-12821 8

Insights Induction time (Single pulse) n i / 10-7 mol s -1 Routes from initial stages of the reaction? 4 3 2 1 1 st pulse C 4 C 6 C 5 C 3 0 0.00 0.0 0.5 1.0 1.5 2.0 t / s C3, C4, C5, C6 olefins were observed. 0.15 0.10 0.05 n i / 10-7 mol s -1 0.08 0.06 0.04 0.02 0.00 0.0 0.5 1.0 1.5 2.0 t / s alkylbenzene benzene K. Van der Borght, R. Batchu, V.V. Galvita, K. Alexopoulos, M.F. Reyniers, J.W. Thybaut, G.B. Marin, Angew Chem Int Ed Engl, 55 (2016) 12817-12821 8

Insights Induction time (Single pulse) n i / 10-7 mol s -1 Routes from initial stages of the reaction? 4 3 2 1 1 st pulse C 4 C 6 C 5 C 3 0 0.00 0.0 0.5 1.0 1.5 2.0 t / s C3, C4, C5, C6 olefins were observed. 0.15 0.10 0.05 n i / 10-7 mol s -1 0.08 0.06 0.04 0.02 0.00 0.0 0.5 1.0 1.5 2.0 t / s alkylbenzene benzene K. Van der Borght, R. Batchu, V.V. Galvita, K. Alexopoulos, M.F. Reyniers, J.W. Thybaut, G.B. Marin, Angew Chem Int Ed Engl, 55 (2016) 12817-12821 8

Insights Induction time (Single pulse) Routes from initial stages of the reaction? n i / 10-7 mol s -1 1 st pulse 2.0 1.5 1.0 0.5 C 4 C 6 C 5 C 3 25 th pulse 0.0 0.00 0.0 0.5 1.0 1.5 2.0 t / s C3, C4, C5, C6 olefins were observed. Aromatics also appear. 0.15 0.10 0.05 n i / 10-7 mol s -1 0.08 0.06 0.04 0.02 0.00 0.0 0.5 1.0 1.5 2.0 t / s alkylbenzene benzene K. Van der Borght, R. Batchu, V.V. Galvita, K. Alexopoulos, M.F. Reyniers, J.W. Thybaut, G.B. Marin, Angew Chem Int Ed Engl, 55 (2016) 12817-12821 8

Insights Induction time (Single pulse) Routes from initial stages of the reaction? n i / 10-7 mol s -1 1 st pulse 2.0 1.5 1.0 0.5 C 4 C 6 C 5 C 3 25 th pulse 0.0 0.00 0.0 0.5 1.0 1.5 2.0 t / s C3, C4, C5, C6 olefins were observed. Aromatics also appear. 0.15 0.10 0.05 n i / 10-7 mol s -1 0.08 0.06 0.04 0.02 0.00 0.0 0.5 1.0 1.5 2.0 t / s alkylbenzene benzene K. Van der Borght, R. Batchu, V.V. Galvita, K. Alexopoulos, M.F. Reyniers, J.W. Thybaut, G.B. Marin, Angew Chem Int Ed Engl, 55 (2016) 12817-12821 8

Insights Induction time (Single pulse) Routes from initial stages of the reaction? 1 st pulse 25 th pulse C3, C4, C5, C6 olefins were observed. 400 th pulse Aromatics also appear. Only lower olefins C3 and C4 remained Deactivation? 0.08 n i / 10-7 mol s -1 1.0 0.5 C 4 C 3 C 5 C 6 0.0 0.00 0.0 0.5 1.0 1.5 2.0 t / s 0.15 0.10 0.05 n i / 10-7 mol s -1 0.06 0.04 0.02 0.00 0.0 0.5 1.0 1.5 2.0 t / s alkylbenzene benzene K. Van der Borght, R. Batchu, V.V. Galvita, K. Alexopoulos, M.F. Reyniers, J.W. Thybaut, G.B. Marin, Angew Chem Int Ed Engl, 55 (2016) 12817-12821 8

Insights Surface species (TPD) Ethene conversion with pulse number. - Fresh - After 1 TPD - After 2 TPD Catalyst activity restored by in TPD. 9

Insights Surface species (TPD) Ethene conversion with pulse number. - Fresh - After 1 TPD - After 2 TPD I m/z = 78, a.u. Temperature programmed desorption - Benzene, Alkylated benzene desorbed from the bed. 0.6 0.5 0.4 Benzene Catalyst activity restored by in TPD. 660 680 700 720 740 760 Temperature, K 9

Insights Surface species (TPD) Ethene conversion with pulse number. - Fresh - After 1 TPD - After 2 TPD I m/z = 78, a.u. Temperature programmed desorption - Benzene, Alkylated benzene desorbed from the bed. 0.6 0.5 0.4 Benzene 660 680 700 720 740 760 Temperature, K Catalyst activity restored by in TPD. Aromatic surface species long lived surface intermediates. 9

Insights Overview Gas phase products - Higher olefins - Aromatics Surface species - Aliphatic, C ali * - Aromatic C aro * 10

Insights Overview Gas phase products - Higher olefins - Aromatics Surface species - Aliphatic, C ali * - Aromatic C aro * Role of aliphatic and aromatic surface intermediates? 10

Insights Overview Gas phase products - Higher olefins - Aromatics Surface species - Aliphatic, C ali * - Aromatic C aro * Role of aliphatic and aromatic surface intermediates? Any intermediate products? - Dienes, Cyclodienes 10

Insights Catalytic cracking paths (Single pulse) Butene single-pulse experiments over ZSM-5 at 648 K. 11

Insights Catalytic cracking paths (Single pulse) Butene single-pulse experiments over ZSM-5 at 648 K. Ethene Butene Benzene, Alkylbenzene 2.0 7.5 9 n i, 10-7 mol 1.5 1.0 n i, 10-8 mol 6.0 4.5 n i, 10-10 mol 6 3 0.5 0 50 100 150 200 250 Pulse number 3.0 0 50 100 150 200 250 Pulse number 0 0 50 100 150 200 250 Pulse number 4.5 2.5 n i, 10-8 mol 2.0 1.5 n i, 10-9 mol 3.0 1.5 1.0 0 50 100 150 200 250 Pulse number Propene 0.0 0 50 100 150 200 250 Pulse number Pentene 11

Insights Catalytic cracking paths (Single pulse) Butene single-pulse experiments over ZSM-5 at 648 K. Ethene Butene 2.0 7.5 n i, 10-7 mol 1.5 1.0 n i, 10-8 mol 6.0 4.5 0.5 0 50 100 150 200 250 Pulse number 2.5 3.0 0 50 100 150 200 250 Pulse number 4.5 n i, 10-8 mol 2.0 1.5 n i, 10-9 mol 3.0 1.5 1.0 0 50 100 150 200 250 Pulse number Propene 0.0 0 50 100 150 200 250 Pulse number Pentene 11

Insights Catalytic cracking paths (Single pulse) Butene single-pulse experiments over ZSM-5 at 648 K. Ethene Butene 2.0 7.5 n i, 10-7 mol 1.5 1.0 0.5 0 50 100 150 200 250 Pulse number n i, 10-8 mol 6.0 4.5 3.0 0 50 100 150 200 250 Pulse number Path I 4.5 2.5 n i, 10-8 mol 2.0 1.5 n i, 10-9 mol 3.0 1.5 1.0 0 50 100 150 200 250 Pulse number Propene 0.0 0 50 100 150 200 250 Pulse number Pentene 11

Insights Catalytic cracking paths (Single pulse) Butene single-pulse experiments over ZSM-5 at 648 K. Ethene Butene 2.0 7.5 n i, 10-7 mol 1.5 1.0 0.5 0 50 100 150 200 250 Pulse number n i, 10-8 mol 6.0 4.5 3.0 0 50 100 150 200 250 Pulse number Path I 2.5 4.5 Path II n i, 10-8 mol 2.0 1.5 n i, 10-9 mol 3.0 1.5 1.0 0 50 100 150 200 250 Pulse number Propene 0.0 0 50 100 150 200 250 Pulse number Pentene 11

Insights Catalytic cracking paths (Single pulse) Butene single-pulse experiments over ZSM-5 at 648 K. Ethene Butene 2.0 7.5 n i, 10-7 mol 1.5 1.0 0.5 0 50 100 150 200 250 Pulse number n i, 10-8 mol 6.0 4.5 3.0 0 50 100 150 200 250 Pulse number Path I 2.5 4.5 Path II n i, 10-8 mol 2.0 1.5 n i, 10-9 mol 3.0 1.5 Path III 1.0 0 50 100 150 200 250 Pulse number Propene 0.0 0 50 100 150 200 250 Pulse number Pentene 11

Insights Catalytic cracking paths (Single pulse) Butene single-pulse experiments over ZSM-5 at 648 K. Ethene Butene 2.0 7.5 n i, 10-7 mol 1.5 1.0 0.5 0 50 100 150 200 250 Pulse number n i, 10-8 mol 6.0 4.5 3.0 0 50 100 150 200 250 Pulse number Path I 2.5 4.5 Path II n i, 10-8 mol 2.0 1.5 n i, 10-9 mol 3.0 1.5 Path III 1.0 0 50 100 150 200 250 Pulse number Propene 0.0 0 50 100 150 200 250 Pulse number Pentene Acid catalytic cracking paths by aliphatic surface species. 11

Insights Hydrocarbon pool (Pump Probe) Pump Probe experiment Reactant I Reactant II t Reactant I Reactant II CO Product 2 t/s t/s 12

Insights Hydrocarbon pool (Pump Probe) Pump Probe experiment Reactant I Reactant II t Reactant I Reactant II CO Product 2 t/s t/s Pump pulse(t 0 ) - Higher olefins - Dienes - Cyclodienes - Aromatics Probe pulse(t 0 + 0.1 s) - Ethene Catalyst 12

Insights Hydrocarbon pool (Pump Probe) Pump Probe experiment Reactant I Reactant II t Reactant I Reactant II CO Product 2 t/s t/s Pump pulse(t 0 ) - Higher olefins - Dienes - Cyclodienes - Aromatics Probe pulse(t 0 + 0.1 s) - Ethene Catalyst Ethene_Probe molecule Adspecies_Pump molecules Catalyst 12

DR propene, % DR butene, % 75 50 25 0-25 -50-75 75 50 25 0-25 -50-75 Pump molecules 1-Butene 1-Hexene 1,4-Hexadiene 1,4-CHD Alk.Benz. Propene 1-Hexene 1,4-Hexadiene 1,4-CHD Alk.Benz. Insights Hydrocarbon pool (Pump Probe) 12

DR propene, % DR butene, % 75 50 25 0-25 -50-75 75 50 25 0-25 -50-75 Pump molecules 1-Butene 1-Hexene 1,4-Hexadiene 1,4-CHD Alk.Benz. Propene 1-Hexene 1,4-Hexadiene 1,4-CHD Alk.Benz. Insights Hydrocarbon pool (Pump Probe) 12

DR propene, % DR butene, % 75 50 25 0-25 -50-75 75 50 25 0-25 -50-75 Pump molecules 1-Butene 1-Hexene 1,4-Hexadiene 1,4-CHD Alk.Benz. Propene 1-Hexene 1,4-Hexadiene 1,4-CHD Alk.Benz. Insights Hydrocarbon pool (Pump Probe) Aliphatic surface species catalytic cracking paths 12

DR propene, % DR butene, % 75 50 25 0-25 -50-75 75 50 25 0-25 -50-75 Pump molecules 1-Butene 1-Hexene 1,4-Hexadiene 1,4-CHD Alk.Benz. Propene 1-Hexene 1,4-Hexadiene 1,4-CHD Alk.Benz. Insights Hydrocarbon pool (Pump Probe) 12

DR propene, % DR butene, % 75 50 25 0-25 -50-75 75 50 25 0-25 -50-75 Pump molecules 1-Butene 1-Hexene 1,4-Hexadiene 1,4-CHD Alk.Benz. Propene 1-Hexene 1,4-Hexadiene 1,4-CHD Alk.Benz. Insights Hydrocarbon pool (Pump Probe) 12

DR propene, % DR butene, % 75 50 25 0-25 -50-75 75 50 25 0-25 -50-75 Pump molecules 1-Butene 1-Hexene 1,4-Hexadiene 1,4-CHD Alk.Benz. Propene 1-Hexene 1,4-Hexadiene 1,4-CHD Alk.Benz. Insights Hydrocarbon pool (Pump Probe) 12

DR propene, % DR butene, % 75 50 25 0-25 -50-75 75 50 25 0-25 -50-75 Pump molecules 1-Butene 1-Hexene 1,4-Hexadiene 1,4-CHD Alk.Benz. Propene 1-Hexene 1,4-Hexadiene 1,4-CHD Alk.Benz. Insights Hydrocarbon pool (Pump Probe) Aromatic surface species propene and not butene? 12

Catalyst 1 Catalyst 2 Insights Hydrocarbon pool (Isotope scrambling) Coked with 13 C in pulsed conditions Coked with 12 C in flow conditions 13

Catalyst 1 Catalyst 2 Insights Hydrocarbon pool (Isotope scrambling) Coked with 13 C in pulsed conditions Coked with 12 C in flow conditions 13

Catalyst 1 Insights Hydrocarbon pool (Isotope scrambling) Coked with 13 C in pulsed conditions and switched to 12 C. Catalyst 2 Coked with 12 C in flow conditions and switched to 13 C. Aromatic surface intermediate - Monoalkylaromatics (< 400 nm) 13

Catalyst 1 Catalyst 2 Insights Hydrocarbon pool (Isotope scrambling) Coked with 13 C in pulsed conditions Coked with 12 C in flow conditions and switched to 12 C. and switched to 13 C. 12 C incorporated /- 0.99 0.96 0.93 0.90 Butene Propene 0 50 100 150 200 Aromatic surface intermediate - Monoalkylaromatics (< 400 nm) 12 C incorporated / - 0.9 0.6 0.3 0.0 0 20 40 60 80 100 Pulse number Butene Propene 13

Conclusions R. Batchu et al. Applied Catalysis A: General, 538 (2017) 207-220 14

Conclusions 1 Ethene dimerization is bypassed once sufficient surface species other than ethene are developed. R. Batchu et al. Applied Catalysis A: General, 538 (2017) 207-220 14

Conclusions 1 Ethene dimerization is bypassed once sufficient surface species other than ethene are developed. Higher olefins provided information about the catalytic cracking reaction paths Aliphatic surface species. 2 R. Batchu et al. Applied Catalysis A: General, 538 (2017) 207-220 14

Conclusions 1 Ethene dimerization is bypassed once sufficient surface species other than ethene are developed. 3 Cyclization of dienes connects aliphatic to aromatic surface intermediate and dienes preferred aliphatic surface intermediate towards olefin production. Higher olefins provided information about the catalytic cracking reaction paths Aliphatic surface species. 2 R. Batchu et al. Applied Catalysis A: General, 538 (2017) 207-220 14

Conclusions 1 Ethene dimerization is bypassed once sufficient surface species other than ethene are developed. Higher olefins provided information about the catalytic cracking reaction paths Aliphatic surface species. 2 3 Cyclization of dienes connects aliphatic to aromatic surface intermediate and dienes preferred aliphatic surface intermediate towards olefin production. Aromatic surface intermediate produce olefins depending on aromatics coverage through sidechain alkylation/paring mechanisms. 4 R. Batchu et al. Applied Catalysis A: General, 538 (2017) 207-220 14

Acknowledgements Research Board of Ghent University (BOF) Long Term Structural Methusalem Funding by the Flemish Government 15

Acknowledgements Research Board of Ghent University (BOF) Long Term Structural Methusalem Funding by the Flemish Government Thank you 15