Vitrinite aliphatic groups

The values in Table VII show that 12 nonaromatic rings should be present for nine mean structural units in the case of exinite, 10 in the case of vitrinite, and 16 in the case of micrinite. Since all faiIt -Rnnr) values are higher than the highest ones obtained from the aliphatic group distribution (see Table IV), all samples must contain nonaromatic rings even if the most probable / values... 

The elemental composition of the three maceral groups varies. The vitrinite, which frequently is about 85% of the sample in the United States, is similar to the patent coal. The liptinites are richer in hydrogen, whereas the inertinites are relatively deficient in hydrogen and richer in carbon. The liptinites also contain more aliphatic materials the inertinites are richer in aromatics. The term inertinite refers to the relative chemical inertness of this material, making it especially undesirable for Hquefaction processes because it tends to accumulate in recycled feedstock streams. 

Friedel and Queiser (9) in a discussion of the anthraxylon (vitrinite) spectrum, have stated that aliphatic chains would produce a band at 1464 cm."1 whereas CH2 groups in rings would absorb at 1450 cm."1. Almost all the... 

Aliphatic structures are still of major importance in the second group of resinites, those of the bituminous coals, but aromatic structures are present in significant amounts. The spectra of these resinites display the type of absorption pattern that has come to be associated with other coal macerals, particularly the sporinites and to a large extent the vitrinites. This pattern is established in the resinites of the high volatile bituminous coals. Furthermore, resinites of this group are reactive during carbonization and oxidation processes in which their behavior parallels that of similarly affected vitrinites of equivalent rank. 

Since the structural parameter H.i/C i cannot be determined experimentally, only particular f. values can be derived for example, the theoretically highest fm value follows from the assumption that H i/C i = 3, which means that the entire aliphatic portion consists of CH3 groups. A more realistic value of fm follows if in Equation 2 H.1/C.1 = 2 (the aliphatic portion consists either only of CH2 groups or of the same number CHa and CH groups with or without CH2 groups) is used. These two theoretical but meaningful / values are 0.92 and 0.88 for the micrinite, 0.84 and 0.77 for the vitrinite, and 0.75 and 0.82 for the exinite. 

Quantitative FTIR data were combined with chemical and petrographic data for the 24 vitrinite concentrates and subjected to bivariate and multivariate statistical analyses in order to identify the effects of coal ification on the aliphatic and aromatic functional groups. 

Of particular interest in this study is the nature of the non-aromatic structures in the three main maceral groups. It should be noted that the exinites in both the coals separated by float-sink are 90% sporinite. It has been theorized that small molecules, especially the aliphatics, are fairly mobile at some period during the formation of coal (5,6). The studies which support this theory were done on coals that are very rich in exinites and some contained alginite. Two of the coals chosen in the present work (PSOC 828 and 1103) have a more normal distribution of macerals and yet the pyrolysis results indicate that migration of molecules from the exinites to vitrinite and then incorporation into the macromolecular structure might have occurred. 

---