Deoxygenation of biobased molecules by decarboxylation and decarbonylation – a review on the role of heterogeneous, homogeneous and bio-catalysis

G.J.S. Dawes, E.L. Scott*, J.E.L. Le Notre, J.P.M. Sanders, J.H. Bitter

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

137 Citations (Scopus)

Abstract

Use of biomass is crucial for a sustainable supply of chemicals and fuels for future generations. Compared to fossil feedstocks, biomass is more functionalized and requires defunctionalisation to make it suitable for use. Deoxygenation is an important method of defunctionalisation. While thermal deoxygenation is possible, high energy input and lower reaction selectivity makes it less suitable for producing the desired chemicals and fuels. Catalytic deoxygenation is more successful by lowering the activation energy of the reaction, and when designed correctly, is more selective. Catalytic deoxygenation can be performed in various ways. Here we focus on decarboxylation and decarbonylation. There are several classes of catalysts: heterogeneous, homogeneous, bio- and organocatalysts and all have limitations. Homogeneous catalysts generally have superior selectivity and specificity but separation from the reaction is cumbersome. Heterogeneous catalysts are more readily isolated and can be utilised at high temperatures, however they have lower selectivity in complex reaction mixtures. While bio-catalysts can operate at ambient temperatures, the volumetric productivity is lower. Therefore it is not always apparent in advance which catalyst is the most suitable in terms of conversion and selectivity under optimal process conditions. Here we compare classes of catalysts for the decarboxylation and decarbonylation of biobased molecules and discuss their limitations and advantages. We mainly focus on the activity of the catalysts and find there is a strong correlation between specific activity (turn over frequency) and temperature for metal based catalysts (homogeneous or heterogeneous). Thus one is not more active than the other at the same temperature. Alternatively, enzymes have a higher turnover frequency but drawbacks (low volumetric productivity) should be overcome.
Original languageEnglish
Pages (from-to)3231-3250
JournalGreen Chemistry
Volume17
DOIs
Publication statusPublished - 2015

Keywords

  • alpha-amino-acids
  • nitrogen-containing chemicals
  • aliphatic carboxylic-acids
  • free fatty-acids
  • oxidative decarboxylation
  • levulinic acid
  • renewable resources
  • supercritical water
  • enzymatic catalysis
  • ethanol-production

Fingerprint

Dive into the research topics of 'Deoxygenation of biobased molecules by decarboxylation and decarbonylation – a review on the role of heterogeneous, homogeneous and bio-catalysis'. Together they form a unique fingerprint.

Cite this