Selective Oxidation of D-Galactose over Gold Catalysts

Bright T. Kusema, Betiana C. Campo, Olga A. Simakova, Anne Riika Leino, Krisztián Kordás, Päivi Mäki-Arvela, Tapio Salmi, Dmitry Yu Murzin*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

22 Citations (Scopus)

Abstract

The selective oxidation of D-galactose to galactonic acid over Au/Al 2O 3 was studied isothermally in a semi-batch shaker reactor under pH-controlled conditions at atmospheric pressure. A series of Au/Al 2O 3 catalysts were prepared and calcined at different temperatures to achieve different gold-particle sizes. The catalytic properties of the gold nanoparticles were affected by the cluster size. A detailed comparison of activity and selectivity of these catalysts was made, which demonstrated that Au/Al 2O 3 with a mean particle size of 2.6nm exhibited the highest activity. The influence of the pH value of the reaction medium on the selective oxidation of D-galactose was elucidated. Alkaline conditions were characterized by high catalyst activity and selectivity to aldonic acid. Inhibition of the catalytic activity was observed in the acidic medium. The intermediate species was present at low pH values, and this resulted in low conversion and selectivity to the main product, galactonic acid. The electrochemical potential of the catalyst was correlated to the catalytic activity.

Original languageEnglish
Pages (from-to)1789-1798
Number of pages10
JournalChemCatChem
Volume3
Issue number11
DOIs
Publication statusPublished - Nov 2011
MoE publication typeA1 Journal article-refereed

Keywords

  • D-galactose
  • Gold
  • Nanoparticles
  • Oxidation
  • Surface potential

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