Correction of sideband effects of nuclear magnetic resonance carbon spectrum in coal and its application in coal structure analysis

In the nuclear magnetic resonance (NMR) test of coal, when spinning frequency magic-angle (MAS) is less than range chemical shift anisotropy, serious aromatic carbon sidebands will appear. Existing solutions to sideband effect, such as changing MAS frequency, inserting total suppression (TOSS) pulse sequences, or simply defining peak after 200 ppm peaks generated by peak, multipling identified integral 2 and adding main protonated bridgehead carbon. None these methods can reasonably correct for effect cause errors accurately quantifying structure parameters. Compared with 13C (13C NMR) spectrum without CP-MAS NMR under conditions CP-MAS/TOSS NMR), according shifts four carbons, namely carbon, alkylated oxygen-linked combined first- second-level types carbons were located quantified, they added corresponding in spectrum, thus realizing accurate correction solid-state coal samples. The relative area corrected aliphatic carbonyl (carboxyl) various recalculated, more parameters obtained, which significant studying from a microscopic perspective.