Separation and Purification of Indole from Coal Tar by Supercritical Fluid Extraction

Mamoru Yanagiuchi, Tomonori Kato, Torataro Ueda, Kenji Matubara, Kunio Arai, Hiroshi Inomata, Shozaburo Saito

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


Supercritical fluid extraction was applied to the separation and purification of indole. Indole is important as a feedstock for tryptophan, which is used in the field of biotechnology. Supercritical fluid extraction of coal tar oil including indole was conducted using CO2 and C2H4. Not much indole was extracted, but it was concentrated in the raffinate. To concentrate high-purity indole in the raffinate, ethylene glycol and mono ethanol amine (MEA) were used as additives for supercritical fluid extraction by C2H4. After distillation of the raffinate with MEA was conducted, high-purity indole was obtained. On the basis of these results, a newly developed process was proposed that uses combined supercritical fluid extraction to separate high-purity indole from coal tar oil.

Original languageEnglish
Pages (from-to)153-158
Number of pages6
Issue number2
Publication statusPublished - 1993


  • Coal Tar
  • Indole
  • Purification
  • Separation
  • Supercritical Fluid Extraction

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)

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