Multicomponent paraffin waxes and petroleum solid deposits: structural and thermodynamic state

The X-ray diffraction analyses, carried out on eight commercial and industrial waxes and a heavy crude oil, show the following remarkable results: (i) each multicomponent paraffin wax (from 20 to 33 n-alkanes), which has a continuous distribution of consecutive n-alkanes (19 < n < 53), forms a single orthorhombic solid solution; (ii) the molecule packing identity period along the long c-axis of this solid solution corresponds to a chain length of a hypothetical orthorhombic n-alkane whose carbon atom number is equal to the average carbon atom number of n-alkanes contained in each multicomponent paraffin wax. This multicomponent phase, whose orthorhombic structure is analogous to one of the two intermediate solid solutions, beta(n)' or beta(n)'', of binary and ternary molecular alloys of consecutive n-alkanes, is also observed in the deposit of the heavy crude oil with the presence of an amorphous solid. (C) 1998 Elsevier Science Ltd. All rights reserved.