Evidence of poly-condensed aromatic rings in a Victorian brown coal

Nao Kashimura, Jun ichiro Hayashi, Chun Zhu Li, Chirag Sathe, Tadatoshi Chiba

研究成果: Contribution to journalArticle査読

34 被引用数 (Scopus)

抄録

An attempt was made for obtaining UV/VIS absorption and fluorescence spectra of a whole Victorian brown coal and then examining the presence of aromatic ring systems (ARSs) with poly-condensed rings in the coal. Loy Yang brown coal was subjected to an alkali-promoted depolymerization in an aqueous solution of sodium hydroxide at 473 K and then dissolved nearly completely into the solution. The solution of the solubilized coal was analyzed by UV/VIS absorption and fluorescence spectroscopies. The spectra of the solubilized coal were compared with those of a tar that was produced from the rapid pyrolysis of the coal in a wire-mesh reactor. Absorbance of the solubilized coal per unit molar concentration of aromatic carbon and unit light path length was averaged over 50 nm wavelength intervals in a range from 250 to 600 nm. The averaged absorbance of the solubilized coal was much greater than those of mono-aromatic compounds and lignin at intervals from 400 to 600 nm while comparable to those of tetra- to hexa-aromatic compounds, suggesting that the coal is abundant of ARSs with poly-condensed rings. The fluorescence spectra of the solubilized coal also give indication of the presence of ARSs with three to six condensed rings. Furthermore, the presence of even larger ARSs is evidenced from appreciable difference in apparent quantum yield of the solubilized coal and that of the tar. By comparing the absorption and fluorescence spectra of the solubilized coal with those of the tar, it was revealed that the tar is richer in relatively small poly-ARSs than the solubilized coal while the larger poly-ARSs are abundant in the solubilized coal. Smaller poly-ARSs were thus released from the coal preferentially to larger poly-ARSs during the pyrolysis.

本文言語英語
ページ(範囲)97-107
ページ数11
ジャーナルFuel
83
1
DOI
出版ステータス出版済み - 1 2004
外部発表はい

All Science Journal Classification (ASJC) codes

  • 化学工学(全般)
  • 燃料技術
  • エネルギー工学および電力技術
  • 有機化学

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