ABSTRACT
The wax particles are essentially normal paraffins and slightly branched paraffins, but also naphthenes with long paraffinic chains that may take part in wax formation. Typical wax-forming molecules are sketched in Figure 11.1. Experimental investigations (Bishop et al. 1995) reveal that compounds heavier than approximately C50 are rare in solid wax. This has to do with the paraffin concentration pattern. Normal paraffins and slightly branched isoparaffins are present in considerable concentrations in the lighter C7+ fractions. In the high-molecular-weight fractions, the degree of branching is higher, and the molecules therefore less likely to enter into a solid structure. Figure 11.2 illustrates the qualitative development in molecular structure with increasing molecular weight. Paraffin components with no or little branching are found in high concentrations in the lighter C7+ fractions, but low melting temperatures limit the amount of lighter C7+ components in the formed wax. The solid wax phase is instead dominated by C20-C50 paraffins.
