[Fluorescence spectroscopy characterization of asphaltene liquefied from coal and study of its association structure].
Structure and association of asphaltenes from coal direct hydroliquefaction were studied by fluorescence spectrometry and UV-Vis absorption spectrometry in this paper. The results indicate that asphaltene is aromatic mixtures mainly containing naphthalene nucleus and shows strong fluorescent characteristic. The forming of exciplex between asphaltene and solvent results in the red shift of fluorescence peak and fluorescence quenching of asphaltene that increases with the polarity and electron acceptability. The self-aggregation of asphaltene is formed by non-covalent bond interaction, so that the asphaltene liquefied at higher temperture that shows high aromaticity has stronger association than that liquefied at lower temperature. Aggregation of asphaltene has been found to be a gradual process, in which there is no critical aggregation constant observed, and the inflection point of the plot of apparent fluorescence intensity as a function of asphaltene concentration varies with the excitation wavelength.
Wang
Zhi-Cai
ZC
Anhui Key Laboratory of Clean Coal Conversion & Utilization, School of Chemistry and Chemical Engineering, Anhui University of Technology, Ma'anshan 243002, China. zhicaiw@ahut.edu.cn
Cui
Xue-Ping
XP
Shui
Heng-Fu
HF
Wang
Zu-Shan
ZS
Lei
Zhi-Ping
ZP
Kang
Shi-Gang
SG