Experimental Study for Influence of Surfactants Chemical Microstructures on Wetting Effect about Coal Dust in Tongchuan Mining Area

Table 3

Percentages of different carbon types in ¹³C-NMR spectra of the coal dust.

No.	^13 C/ ppm	Area (%)	Assignment
1	16.356	5.20	Aromatic methyl groups
2	23.275	2.18	Methylene groups
3	32.222	11.20	Methylene groups
4	40.030	7.48	Quaternary carbon
5	46.753	5.34	Quaternary carbon
6	54.118	0.29	Oxygen-linked aliphatic carbon
7	112.792	3.62	Protonated aromatic carbon
8	118.802	8.60	Protonated aromatic carbon
9	128.262	31.86	Protonated aromatic carbon
10	137.363	9.05	Bridged aromatic carbon
11	143.595	9.05	Side-branched aromatic carbon
12	151.576	3.46	Oxygen-linked aromatic carbon
13	156.617	2.66	Oxygen-linked aromatic carbon
14	181.383	1.24	Carboxyl carbon
15	192.122	0.66	Carbonyl carbon