Related Experiment Video
Updated: Jul 11, 2025

Exploring the Radical Nature of a Carbon Surface by Electron Paramagnetic Resonance and a Calibrated Gas Flow
Published on: April 24, 2014
Evolutionary Analysis of Coal Molecular Structure under Different Metamorphism: An Attempt to Use Electron
1Anhui Province Intelligent Underground Exploration and Environmental Geotechnical Engineering Research Center, College of Civil Engineering, Anhui Jianzhu University, Hefei 230601, China.
Abstract:
The metamorphic process of coal is often affected by magma intrusion and stratigraphic tectonic movement. It is of great significance to analyze the evolution characteristics of coal structure under different metamorphisms in the study of coalification. Nineteen coal samples collected from Huainan coalfield (Zhangji coal mine, Panji-4 coal mine, and Xinji-2 coal mine) were tested by electron paramagnetic resonance (EPR) to clarify the average evolution information on organic molecular structure during coal metamorphism. The results showed that compared with deep burial metamorphism, magma intrusion and stratigraphic tectonic stress could deepen the metamorphic degree of coal. For coal samples under three kinds of metamorphism, the relationship between three EPR parameters (free radical concentration Ng, line width ΔH, and Lande factor g) and vitrinite reflectance Rmax0 approximately satisfied a quartic polynomial distribution. At the same time, with the increase of Rmax0, the changes of EPR parameters fluctuated, showing a phased and stepwise trend of change. Compared with related studies, the results showed that there were great differences in the Ng and ΔH distribution between high-rank and medium-rank coals during organic evolution. In this paper, the functional relationship between EPR parameters of coal and Rmax0 under different metamorphisms was constructed, and the internal relationship between them and its influencing factors was analyzed, which provides a reference for the study of molecular structure evolution characteristics of coal in Huainan coalfield.
Related Concept Videos
Electron Paramagnetic Resonance (EPR) Spectroscopy: Organic Radicals
Carbon-13 (¹³C) NMR: Overview
π Electron Effects on Chemical Shift: Overview
π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds
¹³C NMR: ¹H–¹³C Decoupling
A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
Nuclear Magnetic Resonance (NMR): Overview
NMR spectroscopy generates a spectrum where the characteristic absorption frequencies of the sample are...

