Measurements of the solubilities of derivatized amino acids in supercritical carbon dioxide

Joerg Freitag, You Yokoyama, Hidetoshi Kuramochi, Katsuya Kawamoto, Kunio Nagahama, Satoru Kato

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4 Citations (Scopus)


The solubilities of phenylalanine and tyrosine in supercritical carbon dioxide (SCCO2) were measured after derivatization as the N-acetyl amino acid ethyl ester, N-carbobenzoxy amino acid and N-acetyl amino acid. Using an SCCO2 flow system, a measuring method of the saturated solubilities of the derivatized amino acids was established in which the contact height of the extraction cell, i.e. a packed column, is increased till the concentration of a derivatized amino acid at the exit of the cell reaches a plateau. The solubilities of N-acetyl phenylalanine ethyl ester (APEE) exceeded 0.001 mole fraction, which is higher than those of caffeine produced in industrial SCCO2 processes. A possible way of separating the amino acid mixtures using polarity differences in different amino acid side chains was demonstrated using the solubility data of the N-acetyl-amino acid ethyl esters in SCCO2, as the solubilities of APEE are higher than those of N-acetyl tyrosine ethyl ester by two orders of magnitude.

Original languageEnglish
Pages (from-to)201-206
Number of pages6
JournalFluid Phase Equilibria
Issue number2
Publication statusPublished - Aug 25 2007
Externally publishedYes


  • Amino acid derivative
  • Flow system
  • Solubility
  • Supercritical carbon dioxide

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry


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