Isomerization of linoleic acid over supported metal catalysts

Andreas Bernas, Narendra Kumar, Päivi Mäki-Arvela, Natalya V. Kul'kova, Bjarne Holmbom, Tapio Salmi, Dmitry Yu Murzin*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

74 Citations (Scopus)


Heterogeneous supported metal catalysts were applied for the isomerization reaction of linoleic acid (cis-9,cis-12-octadecadienoic acid) to conjugated linoleic acid (CLA) between 80 and 120°C in a diluted system. Ru, Ni, Pd, Pt, Rh, Ir, Os, and bimetallic Pt-Rh supported by activated carbon, Al2O3, SiO2Al2O3, MCM-22, H-MCM-41, H-Y, and H-β were screened. Catalyst characterization was done by XRD, X-ray fluorescence, XPS, H2-TPD, DCP-AES, and nitrogen adsorption techniques. The isomerization reaction was conducted batchwise in both 1-octanol and n-decane as solvents. Reactions taking place were the isomerization of linoleic acid to CLA, hydrogenation of linoleic acid and CLA to monounsaturated octadecenoic acids (oleic acid, elaidic acid, cis-vaccenic acid, and trans-vaccenic acid), as well as the further hydrogenation of monounsaturated acids to stearic acid (n-octadecanoic acid) with isomerization and hydrogenation being two competing parallel reactions. The isomerization reaction was enhanced by catalyst preactivation under hydrogen. The presence of chemisorbed hydrogen increased the conversion but reduced the isomerization selectivity. Ru and Ni showed the best isomerization properties whereas Pd favored the double bond hydrogenation reaction.

Original languageEnglish
Pages (from-to)257-275
Number of pages19
JournalApplied Catalysis A: General
Issue number2
Publication statusPublished - 10 Jun 2003
MoE publication typeA1 Journal article-refereed


  • Conjugated linoleic acid (CLA)
  • Double bond migration
  • Functional food
  • Hydrogenation
  • Isomerization
  • Linoleic acid
  • Supported metal catalysts


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