Catalytic routes to fuels from C1 and oxygenate molecules

Handle URI:
http://hdl.handle.net/10754/624998
Title:
Catalytic routes to fuels from C1 and oxygenate molecules
Authors:
Wang, Shuai; Agirrezabal-Telleria, Iker; Bhan, Aditya; Simonetti, Dante; Takanabe, Kazuhiro ( 0000-0001-5374-9451 ) ; Iglesia, Enrique
Abstract:
This account illustrates concepts in chemical kinetics underpinned by the formalism of transition state theory using catalytic processes that enable the synthesis of molecules suitable as fuels from C-1 and oxygenate reactants. Such feedstocks provide an essential bridge towards a carbon-free energy future, but their volatility and low energy density require the formation of new C-C bonds and the removal of oxygen. These transformations are described here through recent advances in our understanding of the mechanisms and site requirements in catalysis by surfaces, with emphasis on enabling concepts that tackle ubiquitous reactivity and selectivity challenges. The hurdles in forming the first C-C bond from C-1 molecules are illustrated by the oxidative coupling of methane, in which surface O-atoms form OH radicals from O-2 and H2O molecules. These gaseous OH species act as strong H-abstractors and activate C-H bonds with earlier transition states than oxide surfaces, thus rendering activation rates less sensitive to the weaker C-H bonds in larger alkane products than in CH4 reactants. Anhydrous carbonylation of dimethyl ether forms a single C-C bond on protons residing within inorganic voids that preferentially stabilize the kinetically-relevant transition state through van der Waals interactions that compensate for the weak CO nucleophile. Similar solvation effects, but by intrapore liquids instead of inorganic hosts, also become evident as alkenes condense within MCM-41 channels containing isolated Ni2+ active sites during dimerization reactions. Intrapore liquids preferentially stabilize transition states for C-C bond formation and product desorption, leading to unprecedented reactivity and site stability at sub-ambient temperatures and to 1-alkene dimer selectivities previously achieved only on organometallic systems with co-catalysts or activators. C-1 homologation selectively forms C-4 and C-7 chains with a specific backbone (isobutane, triptane) on solid acids, because of methylative growth and hydride transfer rates that reflect the stability of their carbenium ion transition states and are unperturbed by side reactions at low temperatures. Aldol condensation of carbonyl compounds and ketonization of carboxylic acids form new C-C bonds concurrently with O-removal. These reactions involve analogous elementary steps and occur on acid-base site pairs on TiO2 and ZrO2 catalysts. Condensations are limited by a-H abstraction to form enolates via concerted interactions with predominantly unoccupied acid-base pairs. Ketonization is mediated instead by C-C bond formation between hydroxy-enolates and monodentate carboxylates on site pairs nearly saturated by carboxylates. Both reactions are rendered practical through bifunctional strategies, in which H-2 and a Cu catalyst function scavenge unreactive intermediates, prevent sequential reactions and concomitant deactivation, and remove thermodynamic bottlenecks. Alkanal-alkene Prins condensations on solid acids occur concurrently with alkene dimerization and form molecules with new C-C bonds as skeletal isomers unattainable by other routes. Their respective transition states are of similar size, leading to selectivities that cannot sense the presence of a confining host.; Prins condensation reactions benefit from weaker acid sites because their transition states are less charged than those for oligomerization and consequently less sensitive to conjugate anions that become less stable as acids weaken.
KAUST Department:
KAUST Catalysis Center (KCC); Physical Sciences and Engineering (PSE) Division
Citation:
Wang S, Agirrezabal-Telleria I, Bhan A, Simonetti D, Takanabe K, et al. (2017) Catalytic routes to fuels from C1 and oxygenate molecules. Faraday Discuss 197: 9–39. Available: http://dx.doi.org/10.1039/c7fd00018a.
Publisher:
Royal Society of Chemistry (RSC)
Journal:
Faraday Discuss.
Issue Date:
23-Feb-2017
DOI:
10.1039/c7fd00018a
Type:
Article
ISSN:
1359-6640; 1364-5498
Sponsors:
The work described here represents contributions also from Patricia Cheung and John Ahn, in addition to those of the co-authors, who also acknowledge collaborations with Jay Labinger, John Bercaw, and Glenn Sunley in the C<INF>1</INF> homologation and carbonylation studies. The financial support by BP, p.l.c. for all the examples shown and by the Marie Sklodowska Curie Fellowship Program, and the Vermeulen Chair Endowment Fund at the University of California-Berkeley for the dimerization studies are acknowledged with thanks.
Additional Links:
http://pubs.rsc.org/en/Content/ArticleLanding/2017/FD/C7FD00018A#!divAbstract
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division; KAUST Catalysis Center (KCC)

Full metadata record

DC FieldValue Language
dc.contributor.authorWang, Shuaien
dc.contributor.authorAgirrezabal-Telleria, Ikeren
dc.contributor.authorBhan, Adityaen
dc.contributor.authorSimonetti, Danteen
dc.contributor.authorTakanabe, Kazuhiroen
dc.contributor.authorIglesia, Enriqueen
dc.date.accessioned2017-06-14T12:17:32Z-
dc.date.available2017-06-14T12:17:32Z-
dc.date.issued2017-02-23en
dc.identifier.citationWang S, Agirrezabal-Telleria I, Bhan A, Simonetti D, Takanabe K, et al. (2017) Catalytic routes to fuels from C1 and oxygenate molecules. Faraday Discuss 197: 9–39. Available: http://dx.doi.org/10.1039/c7fd00018a.en
dc.identifier.issn1359-6640en
dc.identifier.issn1364-5498en
dc.identifier.doi10.1039/c7fd00018aen
dc.identifier.urihttp://hdl.handle.net/10754/624998-
dc.description.abstractThis account illustrates concepts in chemical kinetics underpinned by the formalism of transition state theory using catalytic processes that enable the synthesis of molecules suitable as fuels from C-1 and oxygenate reactants. Such feedstocks provide an essential bridge towards a carbon-free energy future, but their volatility and low energy density require the formation of new C-C bonds and the removal of oxygen. These transformations are described here through recent advances in our understanding of the mechanisms and site requirements in catalysis by surfaces, with emphasis on enabling concepts that tackle ubiquitous reactivity and selectivity challenges. The hurdles in forming the first C-C bond from C-1 molecules are illustrated by the oxidative coupling of methane, in which surface O-atoms form OH radicals from O-2 and H2O molecules. These gaseous OH species act as strong H-abstractors and activate C-H bonds with earlier transition states than oxide surfaces, thus rendering activation rates less sensitive to the weaker C-H bonds in larger alkane products than in CH4 reactants. Anhydrous carbonylation of dimethyl ether forms a single C-C bond on protons residing within inorganic voids that preferentially stabilize the kinetically-relevant transition state through van der Waals interactions that compensate for the weak CO nucleophile. Similar solvation effects, but by intrapore liquids instead of inorganic hosts, also become evident as alkenes condense within MCM-41 channels containing isolated Ni2+ active sites during dimerization reactions. Intrapore liquids preferentially stabilize transition states for C-C bond formation and product desorption, leading to unprecedented reactivity and site stability at sub-ambient temperatures and to 1-alkene dimer selectivities previously achieved only on organometallic systems with co-catalysts or activators. C-1 homologation selectively forms C-4 and C-7 chains with a specific backbone (isobutane, triptane) on solid acids, because of methylative growth and hydride transfer rates that reflect the stability of their carbenium ion transition states and are unperturbed by side reactions at low temperatures. Aldol condensation of carbonyl compounds and ketonization of carboxylic acids form new C-C bonds concurrently with O-removal. These reactions involve analogous elementary steps and occur on acid-base site pairs on TiO2 and ZrO2 catalysts. Condensations are limited by a-H abstraction to form enolates via concerted interactions with predominantly unoccupied acid-base pairs. Ketonization is mediated instead by C-C bond formation between hydroxy-enolates and monodentate carboxylates on site pairs nearly saturated by carboxylates. Both reactions are rendered practical through bifunctional strategies, in which H-2 and a Cu catalyst function scavenge unreactive intermediates, prevent sequential reactions and concomitant deactivation, and remove thermodynamic bottlenecks. Alkanal-alkene Prins condensations on solid acids occur concurrently with alkene dimerization and form molecules with new C-C bonds as skeletal isomers unattainable by other routes. Their respective transition states are of similar size, leading to selectivities that cannot sense the presence of a confining host.en
dc.description.abstractPrins condensation reactions benefit from weaker acid sites because their transition states are less charged than those for oligomerization and consequently less sensitive to conjugate anions that become less stable as acids weaken.en
dc.description.sponsorshipThe work described here represents contributions also from Patricia Cheung and John Ahn, in addition to those of the co-authors, who also acknowledge collaborations with Jay Labinger, John Bercaw, and Glenn Sunley in the C<INF>1</INF> homologation and carbonylation studies. The financial support by BP, p.l.c. for all the examples shown and by the Marie Sklodowska Curie Fellowship Program, and the Vermeulen Chair Endowment Fund at the University of California-Berkeley for the dimerization studies are acknowledged with thanks.en
dc.publisherRoyal Society of Chemistry (RSC)en
dc.relation.urlhttp://pubs.rsc.org/en/Content/ArticleLanding/2017/FD/C7FD00018A#!divAbstracten
dc.titleCatalytic routes to fuels from C1 and oxygenate moleculesen
dc.typeArticleen
dc.contributor.departmentKAUST Catalysis Center (KCC)en
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalFaraday Discuss.en
dc.contributor.institutionDepartment of Chemical Engineering, University of California at Berkeley, Chemical Sciences Division, E. O. Lawrence Berkeley National Laboratory, Berkeley, USAen
dc.contributor.institutionDepartment of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455en
dc.contributor.institutionDepartment of Chemical and Biomolecular Engineering, University of California at Los Angeles, Los Angeles, CA, 90095en
kaust.authorTakanabe, Kazuhiroen
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