residue as the raw material. As one of the preconceived raw material to produce high-quality coal-based carbon material, the changes of structure of CLP during liquid-phase carbonization process have been detailed investigated in this study. Actually, FTIR and curve-fitted method were used to quantitative analyze the aromaticity index (Iar), the ratio of CH3/ CH2, and basic functional groups (C=C, C=O, and C–O) of CLP and its liquid-phase carbonization products. Polarizing microscope, XRD and curve-fitted methods were used to characterize the microstructures of CLP and derived products. The results show that, branched chain and C=O group are the active reaction point in liquid-phase carbonization process. What’s more, 450 °C is a critical temperature point on the severe thermal polycondensation of CLP. The XRD and curve-fitted analysis of CLP and its liquid-phase carbonization products shows that, the stacking height (Lc), parallel layers (N), and the numbers of aromatic ring in each layer (n) are gradually larger with the improve of liquid-phase carbonization temperature.

Abstract
    1 Introduction
    2 Materials and experiments
        2.1 Preparation and properties of CLP
        2.2 Liquid-phase carbonization of CLP
        2.3 Characterization of samples
            2.3.1 Ultimate analysis
            2.3.2 FTIR spectroscopy measurements
            2.3.3 Polarizing microscope analysis
            2.3.4 XRD analysis
            2.3.5 Curve-fitting analysis
    3 Results and discussion
        3.1 Distribution of elements in samples
        3.2 Changes of chemical structure during liquid-phase carbonization process
            3.2.1 Changes in aromaticity index and branched chain index
            3.2.2 Changes in basic functional groups
            3.2.3 Change in substitution of aromatic hydrogen
        3.3 Changes of polaroid microstructure during liquid-phase carbonization
        3.4 Changes of carbon stacking structure during liquid-phase carbonization
    4 Conclusion
    Acknowledgements 
    References

• Yaming Zhu(Engineering Research Center of Advanced Coal Coking and Efficient Use of Coal Resources, Institute of Chemical Engineering, University of Science and Technology Liaoning/Key Laboratory of Chemical Metallurgy Liaoning Province, University of Science and Technology Liaoning)
• Xuefei Zhao(Engineering Research Center of Advanced Coal Coking and Efficient Use of Coal Resources, Institute of Chemical Engineering, University of Science and Technology Liaoning/Key Laboratory of Chemical Metallurgy Liaoning Province, University of Science and Technology Liaoning)
• Ji Yuan(Engineering Research Center of Advanced Coal Coking and Efficient Use of Coal Resources, Institute of Chemical Engineering, University of Science and Technology Liaoning)
• Chunlei Zhao(Engineering Research Center of Advanced Coal Coking and Efficient Use of Coal Resources, Institute of Chemical Engineering, University of Science and Technology Liaoning)
• Chaoshuai Hu(Engineering Research Center of Advanced Coal Coking and Efficient Use of Coal Resources, Institute of Chemical Engineering, University of Science and Technology Liaoning)