Solvent fractions, aromatic character

Solvent fractions of coal liquids such as oils, resins, asphaltenes, and carboids may be separated because of their different polarity, molecular weights, and degree of aromatic character. The composition of coal liquids appears to be more closely related to the liquefaction process used rather than to the type of coal used. For example, oils and resins produced in SRC processes appear to have higher molecular weight, more aromatic average molecules than those contained in either pyrolysis or catalyzed hydrogenation coal liquids. This suggests less breakdown of coal and coal liquefaction intermediates to smaller. 

Humic acids from two lakes (Lakes Haruna and Kizaki) were separated by organic solvents into various fractions and characterized by H NMR spectroscopy (Ishiwatari, 1973). The results clearly showed the lake humic acids to be aliphatic in character (presence of a large peak in 1.0-1.4 ppm (8 value) range characteristic of acyclic methylenes) with no aromatic protons (absence of a peak in 6.0-8.0 ppm range). The lack of aromatic protons could be... 

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