Structural Characterisation of Asphaltenes during Residue Hydrotreatment with Light Cycle Oil as an Additive

Table 3

Carbon and hydrogen types obtained by ¹³C-NMR and ¹H-NMR spectroscopy.

Subject	Factor	Chemical shift (ppm)	Detail	Reference
Aromatic carbon	CAr	100~170	Unsaturated sp^2, Ca	a
	CAr-O	140~170	Oxygenated aromatic carbon atoms to phenolic hydroxyl, methoxy, and aromatic ether oxygen atoms	[25]
	CAr-H	129–140	Aromatic carbon atoms to hydrogen
	CAr-C	100~129	Bridgehead and substituted aromatic carbon atoms bound to hydroaromatic CH2 carbon and alkyl side chains
Aliphatic carbon	CAli	−10~70	Saturated sp^3, δCs	a
	CA1	21.9~60	CH2 carbon	[26]
	CA2	17~21.9	CH3 alpha to aromatic ring
	CA3	8.5~17	Ethyl and further alkyl to aromatic ring carbon content
Aromatic hydrogen	HAr	5~10	δCHa	a
		8.3~8.9	Some tri- and tetra-aromatic rings	[27]
	Hdi+	7.2~8.3	Diaromatic and most of tri- and tetra-aromatic rings
	Hmono	6.0~7.2	Mono-aromatic ring
Aliphatic hydrogen	HAli	−0.5~5	Aliphatic hydrogen	a
	Hα	2.0~4.0	δα-	[28]
	Hβ	1.05~2.0	δβ-
	Hγ	0.3~1.0	δγ-

ASTM D5292-99 (2004) Standard Test Method for Aromatic Carbon Contents of Hydrocarbon Oils by HR-NMR.