Tuning solid catalysts to control regioselectivity in cross aldol condensations with unsymmetrical ketones for biomass conversion

Koushik Ponnuru, Jinesh C. Manayil, Hong Je Cho, Amin Osatiashtiani, Wei Fan, Karen Wilson, Friederike C. Jentoft

Research output: Contribution to journalArticle

Abstract

Several families of catalysts characterized by differenttypes of acid and base sites were developed to steer regioselectivity in the aldol condensation of unsymmetrical ketones. The catalysts were propyl sulfonicacid (PrSO3H)functionalized SBA-15 with various acid loadings and with or without hydrophobization by octyl groups (Oc); isomorphously substituted BEA zeotypes; and sulfated zirconias with various sulfate loadings. Benzaldehyde and 2-butanone served as test reactants at a temperature of 140 ◦C. Sulfonic acidfunctionalized catalysts preferentially formed branched condensation product and metal-substituted BEA zeotypes selectively formed linear condensation product. Maximum condensation product yields were 65% branched at 98% conversion with the highest site density Oc/PrSO3H/SBA-15 and 76% linear at 94% conversion with Sn-BEA. Sulfated zirconia catalysts were less selective. Product distributions analyzed at different conversions revealed how kinetics and equilibria of addition and dehydration govern
regioselectivity. Further observations were: 1. Increasing the acid site density significantly increased the turnover frequency for PrSO3H/SBA-15, suggesting a cooperative effect between adjacent acid sites. 2. Brønsted acid sites catalyzed an undesired side reaction, the cleavage of the branched addition product to
-methyl styrene and acetic acid. This reaction was suppressed by hydrophobizing the surface through octyl co-functionalization. 3. Deactivation upon re-use was generally slight, and Sn-BEA could be fully regenerated by calcination.
Original languageEnglish
JournalMolecular Catalysis
Early online date26 Nov 2017
DOIs
Publication statusPublished - 26 Nov 2017

Fingerprint

Regioselectivity
biomass
Ketones
ketones
Condensation
Biomass
Tuning
condensation
tuning
catalysts
acids
Catalysts
Acids
products
Styrene
Dehydration
Acetic acid
reuse
Acetic Acid
Zirconia

Keywords

  • Ordered mesoporous materials
  • Titanium beta zeolite
  • Cross aldol condensation
  • Carbon-carbon coupling
  • Reaction pathways

Cite this

Ponnuru, Koushik ; Manayil, Jinesh C. ; Cho, Hong Je ; Osatiashtiani, Amin ; Fan, Wei ; Wilson, Karen ; Jentoft, Friederike C. / Tuning solid catalysts to control regioselectivity in cross aldol condensations with unsymmetrical ketones for biomass conversion. In: Molecular Catalysis. 2017.
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abstract = "Several families of catalysts characterized by differenttypes of acid and base sites were developed to steer regioselectivity in the aldol condensation of unsymmetrical ketones. The catalysts were propyl sulfonicacid (PrSO3H)functionalized SBA-15 with various acid loadings and with or without hydrophobization by octyl groups (Oc); isomorphously substituted BEA zeotypes; and sulfated zirconias with various sulfate loadings. Benzaldehyde and 2-butanone served as test reactants at a temperature of 140 ◦C. Sulfonic acidfunctionalized catalysts preferentially formed branched condensation product and metal-substituted BEA zeotypes selectively formed linear condensation product. Maximum condensation product yields were 65{\%} branched at 98{\%} conversion with the highest site density Oc/PrSO3H/SBA-15 and 76{\%} linear at 94{\%} conversion with Sn-BEA. Sulfated zirconia catalysts were less selective. Product distributions analyzed at different conversions revealed how kinetics and equilibria of addition and dehydration governregioselectivity. Further observations were: 1. Increasing the acid site density significantly increased the turnover frequency for PrSO3H/SBA-15, suggesting a cooperative effect between adjacent acid sites. 2. Br{\o}nsted acid sites catalyzed an undesired side reaction, the cleavage of the branched addition product to-methyl styrene and acetic acid. This reaction was suppressed by hydrophobizing the surface through octyl co-functionalization. 3. Deactivation upon re-use was generally slight, and Sn-BEA could be fully regenerated by calcination.",
keywords = "Ordered mesoporous materials, Titanium beta zeolite, Cross aldol condensation, Carbon-carbon coupling, Reaction pathways",
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Tuning solid catalysts to control regioselectivity in cross aldol condensations with unsymmetrical ketones for biomass conversion. / Ponnuru, Koushik; Manayil, Jinesh C.; Cho, Hong Je; Osatiashtiani, Amin; Fan, Wei; Wilson, Karen; Jentoft, Friederike C.

In: Molecular Catalysis, 26.11.2017.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Tuning solid catalysts to control regioselectivity in cross aldol condensations with unsymmetrical ketones for biomass conversion

AU - Ponnuru, Koushik

AU - Manayil, Jinesh C.

AU - Cho, Hong Je

AU - Osatiashtiani, Amin

AU - Fan, Wei

AU - Wilson, Karen

AU - Jentoft, Friederike C.

PY - 2017/11/26

Y1 - 2017/11/26

N2 - Several families of catalysts characterized by differenttypes of acid and base sites were developed to steer regioselectivity in the aldol condensation of unsymmetrical ketones. The catalysts were propyl sulfonicacid (PrSO3H)functionalized SBA-15 with various acid loadings and with or without hydrophobization by octyl groups (Oc); isomorphously substituted BEA zeotypes; and sulfated zirconias with various sulfate loadings. Benzaldehyde and 2-butanone served as test reactants at a temperature of 140 ◦C. Sulfonic acidfunctionalized catalysts preferentially formed branched condensation product and metal-substituted BEA zeotypes selectively formed linear condensation product. Maximum condensation product yields were 65% branched at 98% conversion with the highest site density Oc/PrSO3H/SBA-15 and 76% linear at 94% conversion with Sn-BEA. Sulfated zirconia catalysts were less selective. Product distributions analyzed at different conversions revealed how kinetics and equilibria of addition and dehydration governregioselectivity. Further observations were: 1. Increasing the acid site density significantly increased the turnover frequency for PrSO3H/SBA-15, suggesting a cooperative effect between adjacent acid sites. 2. Brønsted acid sites catalyzed an undesired side reaction, the cleavage of the branched addition product to-methyl styrene and acetic acid. This reaction was suppressed by hydrophobizing the surface through octyl co-functionalization. 3. Deactivation upon re-use was generally slight, and Sn-BEA could be fully regenerated by calcination.

AB - Several families of catalysts characterized by differenttypes of acid and base sites were developed to steer regioselectivity in the aldol condensation of unsymmetrical ketones. The catalysts were propyl sulfonicacid (PrSO3H)functionalized SBA-15 with various acid loadings and with or without hydrophobization by octyl groups (Oc); isomorphously substituted BEA zeotypes; and sulfated zirconias with various sulfate loadings. Benzaldehyde and 2-butanone served as test reactants at a temperature of 140 ◦C. Sulfonic acidfunctionalized catalysts preferentially formed branched condensation product and metal-substituted BEA zeotypes selectively formed linear condensation product. Maximum condensation product yields were 65% branched at 98% conversion with the highest site density Oc/PrSO3H/SBA-15 and 76% linear at 94% conversion with Sn-BEA. Sulfated zirconia catalysts were less selective. Product distributions analyzed at different conversions revealed how kinetics and equilibria of addition and dehydration governregioselectivity. Further observations were: 1. Increasing the acid site density significantly increased the turnover frequency for PrSO3H/SBA-15, suggesting a cooperative effect between adjacent acid sites. 2. Brønsted acid sites catalyzed an undesired side reaction, the cleavage of the branched addition product to-methyl styrene and acetic acid. This reaction was suppressed by hydrophobizing the surface through octyl co-functionalization. 3. Deactivation upon re-use was generally slight, and Sn-BEA could be fully regenerated by calcination.

KW - Ordered mesoporous materials

KW - Titanium beta zeolite

KW - Cross aldol condensation

KW - Carbon-carbon coupling

KW - Reaction pathways

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UR - http://doi.org/10.17036/researchdata.aston.ac.uk.00000325

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DO - 10.1016/j.mcat.2017.11.005

M3 - Article

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