Coal liquid derived from hydrogenolysis of Akabira coal was performed a separation into compound types by means of silica-alumina gel dual packed liquid chroma-tography modified partly USBM-API method. Respective fractions obtained were investiga-ted on quantitative analyses of
13C-NMR measurement varing the pulse interval time to obtain information concerning relaxation time for main carbon signals and using the technique of ordinary broad band proton decoupling, gated decoupling and proton coupling method. Contents of aromatic carbon derived from gated decoupling technique which can be suppressed the NOE effect, agree fairly with the results from proton coupling technique which enable to get quantitative results without NOE effect.
Procedure of structural analyses for unit structure was derived by using the results of
13C-NMR spectra on a combination with
1H-NMR results in order to avoid uncertain assu-mption made when the Brown-Ladner equations are used. The structural analysis adopted can derive directly the content of aromatic carbon and the ratio of atomic hydrogen to carbon on aliphatic substitution attached to aromatic rings, consequently accurate structural parameter are able to be analyzed.
Fr-p eluted firstly with cyclohexane on chromatographic separation, showed
13C-NMR signal assigned to typical long n-paraffine at 14, 23, 32, 29 and 29. 5ppm and are estimated to be consisted of an average of 22 carbon length n-paraffine. The n-paraffine content in this fraction is about 46 wt.%. For Fr-M, it was found to be constituted from one to two aromatic rings, for Fr-D and Fr-T two and three aromatic rings respectively, indicating to be accomplished a efficient separation into compound types. As the aromatic ring number increases (from Fr-M to Fr-T), the fa values increase gradually from 0.42 to 0.69. How-ever, the total number of carbon in each structural unit does not change largely.
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