Ga/HZSM-5 catalysed acetic acid ketonisation for upgrading of biomass pyrolysis vapours

Hessam Jahangiri; Amin Osatiashtiani; Miloud Ouadi; Andreas Hornung; Adam F. Lee; Karen Wilson

doi:10.3390/catal9100841

Ga/HZSM-5 catalysed acetic acid ketonisation for upgrading of biomass pyrolysis vapours

Hessam Jahangiri, Amin Osatiashtiani, Miloud Ouadi, Andreas Hornung, Adam F. Lee, Karen Wilson

Chemical Engineering

Research output: Contribution to journal › Article › peer-review

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Abstract

Pyrolysis bio-oils contain significant amounts of carboxylic acids which limit their utility as biofuels. Ketonisation of carboxylic acids within biomass pyrolysis vapours is a potential route to upgrade the energy content and stability of the resulting bio-oil condensate, but requires active, selective and coke-resistant solid acid catalysts. Here we explore the vapour phase ketonisation of acetic acid over Ga-doped HZSM-5. Weak Lewis acid sites were identified as the active species responsible for acetic acid ketonisation to acetone at 350 °C and 400 °C. Turnover frequencies were proportional to Ga loading, reaching ~6 min−1 at 400 °C for 10Ga/HZSM-5. Selectivity to the desired acetone product correlated with the weak:strong acid site ratio, being favoured over weak Lewis acid sites and reaching 30% for 10Ga/HZSM-5. Strong Brønsted acidity promoted competing unselective reactions and carbon laydown. 10Ga/HZSM-5 exhibited good stability for over 5 h on-stream acetic acid ketonisation.

Original language	English
Article number	841
Pages (from-to)	1-13
Number of pages	13
Journal	Catalysts
Volume	9
Issue number	10
DOIs	https://doi.org/10.3390/catal9100841
Publication status	Published - 11 Oct 2019

Keywords

Pyrolysis
Ketonisation
Bio-oil
Turnover frequencies (TOFs)

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10.3390/catal9100841Licence: Creative Commons: Attribution (CC BY)

Jahangiri_et_al_Ga/HZSM-5_catalysed_acetic_acid_ketonisation_Catalysts_2019
Jahangiri, H, Osatiashtiani, A, Ouadi, M, Hornung, A, Lee, AF & Wilson, K (2019), 'Ga/HZSM-5 catalysed acetic acid ketonisation for upgrading of biomass pyrolysis vapours', Catalysts, vol. 9, no. 10, 841, pp. 1-13. © 2019 by the authors. Licensee MDPI, Basel, Switzerland. https://doi.org/10.3390/catal9100841
Final published version, 1.34 MBLicence: Creative Commons: Attribution (CC BY)
Jahangiri_et_al_Ga/HZSM-5_catalysed_acetic_acid_ketonisation_Catalysts_2019_Supplementary_material
Jahangiri, H, Osatiashtiani, A, Ouadi, M, Hornung, A, Lee, AF & Wilson, K (2019), 'Ga/HZSM-5 catalysed acetic acid ketonisation for upgrading of biomass pyrolysis vapours', Catalysts, vol. 9, no. 10, 841, pp. 1-13. © 2019 by the authors. Licensee MDPI, Basel, Switzerland. https://doi.org/10.3390/catal9100841
Final published version, 2.11 MBLicence: Creative Commons: Attribution (CC BY)

https://www.mdpi.com/2073-4344/9/10/841Licence: Creative Commons: Attribution (CC BY)

Cite this

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title = "Ga/HZSM-5 catalysed acetic acid ketonisation for upgrading of biomass pyrolysis vapours",

abstract = "Pyrolysis bio-oils contain significant amounts of carboxylic acids which limit their utility as biofuels. Ketonisation of carboxylic acids within biomass pyrolysis vapours is a potential route to upgrade the energy content and stability of the resulting bio-oil condensate, but requires active, selective and coke-resistant solid acid catalysts. Here we explore the vapour phase ketonisation of acetic acid over Ga-doped HZSM-5. Weak Lewis acid sites were identified as the active species responsible for acetic acid ketonisation to acetone at 350 °C and 400 °C. Turnover frequencies were proportional to Ga loading, reaching ~6 min−1 at 400 °C for 10Ga/HZSM-5. Selectivity to the desired acetone product correlated with the weak:strong acid site ratio, being favoured over weak Lewis acid sites and reaching 30% for 10Ga/HZSM-5. Strong Br{\o}nsted acidity promoted competing unselective reactions and carbon laydown. 10Ga/HZSM-5 exhibited good stability for over 5 h on-stream acetic acid ketonisation.",

keywords = "Pyrolysis, Ketonisation, Bio-oil, Turnover frequencies (TOFs)",

author = "Hessam Jahangiri and Amin Osatiashtiani and Miloud Ouadi and Andreas Hornung and Lee, {Adam F.} and Karen Wilson",

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doi = "10.3390/catal9100841",

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T1 - Ga/HZSM-5 catalysed acetic acid ketonisation for upgrading of biomass pyrolysis vapours

AU - Jahangiri, Hessam

AU - Osatiashtiani, Amin

AU - Ouadi, Miloud

AU - Hornung, Andreas

AU - Lee, Adam F.

AU - Wilson, Karen

PY - 2019/10/11

Y1 - 2019/10/11

N2 - Pyrolysis bio-oils contain significant amounts of carboxylic acids which limit their utility as biofuels. Ketonisation of carboxylic acids within biomass pyrolysis vapours is a potential route to upgrade the energy content and stability of the resulting bio-oil condensate, but requires active, selective and coke-resistant solid acid catalysts. Here we explore the vapour phase ketonisation of acetic acid over Ga-doped HZSM-5. Weak Lewis acid sites were identified as the active species responsible for acetic acid ketonisation to acetone at 350 °C and 400 °C. Turnover frequencies were proportional to Ga loading, reaching ~6 min−1 at 400 °C for 10Ga/HZSM-5. Selectivity to the desired acetone product correlated with the weak:strong acid site ratio, being favoured over weak Lewis acid sites and reaching 30% for 10Ga/HZSM-5. Strong Brønsted acidity promoted competing unselective reactions and carbon laydown. 10Ga/HZSM-5 exhibited good stability for over 5 h on-stream acetic acid ketonisation.

AB - Pyrolysis bio-oils contain significant amounts of carboxylic acids which limit their utility as biofuels. Ketonisation of carboxylic acids within biomass pyrolysis vapours is a potential route to upgrade the energy content and stability of the resulting bio-oil condensate, but requires active, selective and coke-resistant solid acid catalysts. Here we explore the vapour phase ketonisation of acetic acid over Ga-doped HZSM-5. Weak Lewis acid sites were identified as the active species responsible for acetic acid ketonisation to acetone at 350 °C and 400 °C. Turnover frequencies were proportional to Ga loading, reaching ~6 min−1 at 400 °C for 10Ga/HZSM-5. Selectivity to the desired acetone product correlated with the weak:strong acid site ratio, being favoured over weak Lewis acid sites and reaching 30% for 10Ga/HZSM-5. Strong Brønsted acidity promoted competing unselective reactions and carbon laydown. 10Ga/HZSM-5 exhibited good stability for over 5 h on-stream acetic acid ketonisation.

KW - Pyrolysis

KW - Ketonisation

KW - Bio-oil

KW - Turnover frequencies (TOFs)

U2 - 10.3390/catal9100841

DO - 10.3390/catal9100841

M3 - Article

SN - 2073-4344

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JO - Catalysts

JF - Catalysts

IS - 10

M1 - 841

ER -

Ga/HZSM-5 catalysed acetic acid ketonisation for upgrading of biomass pyrolysis vapours

Abstract

Keywords

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