Gas phase selective hydrogenation of phenylacetylene to styrene over Au/Al2O3

Xiaodong Wang* (Corresponding Author), Mark A. Keane

*Corresponding author for this work

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

BACKGROUND: Trace quantities of phenylacetylene can poison styrene polymerisation catalysts. The phenylacetylene content must be less than 10 ppm and selective hydrogenation (to styrene) is viewed as a viable process solution. High styrene selectivities have been achieved in batch liquid phase operations while a switch from conventional batch liquid to continuous gas phase reaction presents process advantages in terms of higher throughput and enhanced productivity. We aim to provide the first direct comparison of Au/Al2O3 and Pd/Al2O3 in gas phase continuous catalytic hydrogenation of phenylacetylene.
RESULTS: TPR reduction generated metal particles at the nano-scale (mean size = 3.0-4.3 nm), with evidence of electron donation from the Al2O3 carrier. Pd/Al2O3 exhibited a greater specific H2 uptake capacity than Au/Al2O3 under reaction conditions to deliver appreciably higher turnover frequencies (TOF) for reaction in excess H2. Stepwise hydrogenation predominated over Au/Al2O3 with 100% selectivity to styrene at 353 K where an increase in temperature favoured subsequent hydrogenation to ethylbenzene. Under the same conditions, Pd/Al2O3 was non-selective, activating styrene to generate ethylbenzene with a greater contribution of direct phenylacetylene hydrogenation to ethylbenzene at higher temperature.
CONCLUSION: Kinetic analysis has revealed stepwise phenylacetylene hydrogenation in excess H2 over Au/Al2O3 with 100% selectivity to styrene. Stepwise hydrogenation also prevailed over Pd/Al2O3 at the lower temperature but surface activation of styrene coupled with enhanced H2 dissociation generated significant ethylbenzene. Decreasing inlet H2/phenylacetylene (to 1 mol/mol) over Pd/Al2O3 lowered rate where the activity/selectivity profile overlapped that exhibited by Au/Al2O3 in excess H2.
Original languageEnglish
Pages (from-to)3772-3779
Number of pages8
JournalJournal of Chemical Technology & Biotechnology
Volume94
Issue number12
Early online date17 Apr 2019
DOIs
Publication statusPublished - 1 Dec 2019

Fingerprint

Styrene
Hydrogenation
Gases
Ethylbenzene
gas phase reaction
liquid
gas
polymerization
turnover
catalyst
electron
kinetics
productivity
metal
Temperature
temperature
Poisons
Liquids
phenylacetylene
Polymerization

Keywords

  • gas phase
  • gold
  • hydrogenation
  • palladium
  • phenylacetylene
  • GOLD NANOPARTICLES
  • ALUMINA-SUPPORTED AU
  • ACETYLENE
  • P-CHLORONITROBENZENE
  • SIZE
  • CARBON NANOTUBES
  • HYDRODECHLORINATION
  • METAL DISPERSION
  • PALLADIUM CATALYSTS
  • PD/SIO2 CATALYSTS

ASJC Scopus subject areas

  • Pollution
  • Waste Management and Disposal
  • Chemical Engineering(all)
  • Biotechnology
  • Fuel Technology
  • Inorganic Chemistry
  • Renewable Energy, Sustainability and the Environment
  • Organic Chemistry

Cite this

Gas phase selective hydrogenation of phenylacetylene to styrene over Au/Al2O3. / Wang, Xiaodong (Corresponding Author); Keane, Mark A.

In: Journal of Chemical Technology & Biotechnology, Vol. 94, No. 12, 01.12.2019, p. 3772-3779.

Research output: Contribution to journalArticle

@article{241a80978ccd4a70b53e77571c26f054,
title = "Gas phase selective hydrogenation of phenylacetylene to styrene over Au/Al2O3",
abstract = "BACKGROUND: Trace quantities of phenylacetylene can poison styrene polymerisation catalysts. The phenylacetylene content must be less than 10 ppm and selective hydrogenation (to styrene) is viewed as a viable process solution. High styrene selectivities have been achieved in batch liquid phase operations while a switch from conventional batch liquid to continuous gas phase reaction presents process advantages in terms of higher throughput and enhanced productivity. We aim to provide the first direct comparison of Au/Al2O3 and Pd/Al2O3 in gas phase continuous catalytic hydrogenation of phenylacetylene.RESULTS: TPR reduction generated metal particles at the nano-scale (mean size = 3.0-4.3 nm), with evidence of electron donation from the Al2O3 carrier. Pd/Al2O3 exhibited a greater specific H2 uptake capacity than Au/Al2O3 under reaction conditions to deliver appreciably higher turnover frequencies (TOF) for reaction in excess H2. Stepwise hydrogenation predominated over Au/Al2O3 with 100{\%} selectivity to styrene at 353 K where an increase in temperature favoured subsequent hydrogenation to ethylbenzene. Under the same conditions, Pd/Al2O3 was non-selective, activating styrene to generate ethylbenzene with a greater contribution of direct phenylacetylene hydrogenation to ethylbenzene at higher temperature.CONCLUSION: Kinetic analysis has revealed stepwise phenylacetylene hydrogenation in excess H2 over Au/Al2O3 with 100{\%} selectivity to styrene. Stepwise hydrogenation also prevailed over Pd/Al2O3 at the lower temperature but surface activation of styrene coupled with enhanced H2 dissociation generated significant ethylbenzene. Decreasing inlet H2/phenylacetylene (to 1 mol/mol) over Pd/Al2O3 lowered rate where the activity/selectivity profile overlapped that exhibited by Au/Al2O3 in excess H2.",
keywords = "gas phase, gold, hydrogenation, palladium, phenylacetylene, GOLD NANOPARTICLES, ALUMINA-SUPPORTED AU, ACETYLENE, P-CHLORONITROBENZENE, SIZE, CARBON NANOTUBES, HYDRODECHLORINATION, METAL DISPERSION, PALLADIUM CATALYSTS, PD/SIO2 CATALYSTS",
author = "Xiaodong Wang and Keane, {Mark A.}",
note = "EPSRC support for free access to the TEM/SEM facility at the University of St Andrews and financial support (to X. Wang) through the Overseas Research Students Award Scheme (ORSAS) are also acknowledged.",
year = "2019",
month = "12",
day = "1",
doi = "10.1002/jctb.6002",
language = "English",
volume = "94",
pages = "3772--3779",
journal = "Journal of Chemical Technology & Biotechnology",
issn = "0268-2575",
publisher = "John Wiley and Sons Ltd",
number = "12",

}

TY - JOUR

T1 - Gas phase selective hydrogenation of phenylacetylene to styrene over Au/Al2O3

AU - Wang, Xiaodong

AU - Keane, Mark A.

N1 - EPSRC support for free access to the TEM/SEM facility at the University of St Andrews and financial support (to X. Wang) through the Overseas Research Students Award Scheme (ORSAS) are also acknowledged.

PY - 2019/12/1

Y1 - 2019/12/1

N2 - BACKGROUND: Trace quantities of phenylacetylene can poison styrene polymerisation catalysts. The phenylacetylene content must be less than 10 ppm and selective hydrogenation (to styrene) is viewed as a viable process solution. High styrene selectivities have been achieved in batch liquid phase operations while a switch from conventional batch liquid to continuous gas phase reaction presents process advantages in terms of higher throughput and enhanced productivity. We aim to provide the first direct comparison of Au/Al2O3 and Pd/Al2O3 in gas phase continuous catalytic hydrogenation of phenylacetylene.RESULTS: TPR reduction generated metal particles at the nano-scale (mean size = 3.0-4.3 nm), with evidence of electron donation from the Al2O3 carrier. Pd/Al2O3 exhibited a greater specific H2 uptake capacity than Au/Al2O3 under reaction conditions to deliver appreciably higher turnover frequencies (TOF) for reaction in excess H2. Stepwise hydrogenation predominated over Au/Al2O3 with 100% selectivity to styrene at 353 K where an increase in temperature favoured subsequent hydrogenation to ethylbenzene. Under the same conditions, Pd/Al2O3 was non-selective, activating styrene to generate ethylbenzene with a greater contribution of direct phenylacetylene hydrogenation to ethylbenzene at higher temperature.CONCLUSION: Kinetic analysis has revealed stepwise phenylacetylene hydrogenation in excess H2 over Au/Al2O3 with 100% selectivity to styrene. Stepwise hydrogenation also prevailed over Pd/Al2O3 at the lower temperature but surface activation of styrene coupled with enhanced H2 dissociation generated significant ethylbenzene. Decreasing inlet H2/phenylacetylene (to 1 mol/mol) over Pd/Al2O3 lowered rate where the activity/selectivity profile overlapped that exhibited by Au/Al2O3 in excess H2.

AB - BACKGROUND: Trace quantities of phenylacetylene can poison styrene polymerisation catalysts. The phenylacetylene content must be less than 10 ppm and selective hydrogenation (to styrene) is viewed as a viable process solution. High styrene selectivities have been achieved in batch liquid phase operations while a switch from conventional batch liquid to continuous gas phase reaction presents process advantages in terms of higher throughput and enhanced productivity. We aim to provide the first direct comparison of Au/Al2O3 and Pd/Al2O3 in gas phase continuous catalytic hydrogenation of phenylacetylene.RESULTS: TPR reduction generated metal particles at the nano-scale (mean size = 3.0-4.3 nm), with evidence of electron donation from the Al2O3 carrier. Pd/Al2O3 exhibited a greater specific H2 uptake capacity than Au/Al2O3 under reaction conditions to deliver appreciably higher turnover frequencies (TOF) for reaction in excess H2. Stepwise hydrogenation predominated over Au/Al2O3 with 100% selectivity to styrene at 353 K where an increase in temperature favoured subsequent hydrogenation to ethylbenzene. Under the same conditions, Pd/Al2O3 was non-selective, activating styrene to generate ethylbenzene with a greater contribution of direct phenylacetylene hydrogenation to ethylbenzene at higher temperature.CONCLUSION: Kinetic analysis has revealed stepwise phenylacetylene hydrogenation in excess H2 over Au/Al2O3 with 100% selectivity to styrene. Stepwise hydrogenation also prevailed over Pd/Al2O3 at the lower temperature but surface activation of styrene coupled with enhanced H2 dissociation generated significant ethylbenzene. Decreasing inlet H2/phenylacetylene (to 1 mol/mol) over Pd/Al2O3 lowered rate where the activity/selectivity profile overlapped that exhibited by Au/Al2O3 in excess H2.

KW - gas phase

KW - gold

KW - hydrogenation

KW - palladium

KW - phenylacetylene

KW - GOLD NANOPARTICLES

KW - ALUMINA-SUPPORTED AU

KW - ACETYLENE

KW - P-CHLORONITROBENZENE

KW - SIZE

KW - CARBON NANOTUBES

KW - HYDRODECHLORINATION

KW - METAL DISPERSION

KW - PALLADIUM CATALYSTS

KW - PD/SIO2 CATALYSTS

UR - http://www.scopus.com/inward/record.url?scp=85064712872&partnerID=8YFLogxK

UR - http://www.mendeley.com/research/gas-phase-selective-hydrogenation-phenylacetylene-styrene-aual-2-o-3

UR - http://pure.abdn.ac.uk:8080/portal/en/researchoutput/gas-phase-selective-hydrogenation-of-phenylacetylene-to-styrene-over-aual2o3(241a8097-8ccd-4a70-b53e-77571c26f054).html

U2 - 10.1002/jctb.6002

DO - 10.1002/jctb.6002

M3 - Article

VL - 94

SP - 3772

EP - 3779

JO - Journal of Chemical Technology & Biotechnology

JF - Journal of Chemical Technology & Biotechnology

SN - 0268-2575

IS - 12

ER -