Degradation of pentoses and hexouronic acids in subcritical water

Chisako Usuki, Yukitaka Kimura, Shuji Adachi

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

The degradation of arabinose, xylose, ribose and lyxose in subcritical water was measured at 200, 220 and 240 °C. Ribose was the most rapidly degraded among the pentoses tested. The degradation of the glucuronic and galacturonic acids proceeded at lower temperatures than that of the pentoses, and was measured at 140, 150 and 160 °C. The degradation processes of the pentoses and hexouronic acids could be expressed by the Weibull model, and the kinetic parameters were then estimated. The activation energy and frequency factor for the degradation of each substrate were estimated from the temperature dependence of the rate constant. The enthalpy-entropy compensation held for the degradation of the pentoses as well as the hexoses, which suggests that the degradation of the hexouronic acids proceeded through a mechanism different from that for the pentoses and hexoses. The molar yield of a pentose to furfural was ca. 0.3 at any temperature, irrespective of the pentose type. Acidic compounds were also formed from the pentoses in proportion to the amount of consumed substrates. The formation of acidic compounds resulted in a rapid decrease in pH.

Original languageEnglish
Pages (from-to)133-137
Number of pages5
JournalChemical Engineering and Technology
Volume31
Issue number1
DOIs
Publication statusPublished - Jan 1 2008
Externally publishedYes

Keywords

  • Degradation
  • Kinetics
  • Monosaccharides
  • Subcritical water

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

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