Lithotype pertrifluoroacetic acid oxidation

Product Composition of Brown Coal Lithotypes Pertrifluoroacetic Acid Oxidation Mixtures... 

Victorian brown coal occurs in five major lithotypes distinguishable by color index and petrography. Advantage has been taken of a rare 100 m continuous core to compare and contrast chemical variations occurring as a function of lithotype classification. For many parameters there is a much greater contrast between the different lithotypes than there is across the depth profile of (nearly) identical lithotypes. Molecular parameters, such as the distributions of hydrocarbons, fatty acids, triterpenoids and pertrifluoroacetic acid oxidation products, together with gross structural parameters derived from IR and C-NMR spectroscopic data, Rock-Eval and elemental analyses and the yields of specific extractable fractions are compared. 

The lithotype profile was investigated in greater detail with the product composition of the different brown coals being reported in Tables 1 and 2. A distinct decrease in the total concentration of detectable oxidation products occurs with darker lithotypes (Table 1). This result is consistent with increasing aromaticity (Figure 2) and the preferential attack on aromatic structures by the pertrifluoroacetic acid reagent. The total destruction of the tertiary structure within the brown coal lithotypes is evidenced by their low yield of insoluble products (Residue) which is primarily composed of mineral matter. 

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