X-RAY DIFFRACTION OF N-PARAFFINS AND STACKED AROMATIC MOLECULES: INSIGHTS INTO THE STRUCTURE OF PETROLEUM ASPHALTENES

Abstract

ABSTRACT X-ray diffraction investigation of normal paraffins and Debye internal interference calculations on stacks of aromatic molecules are used to make inferences about the structure of petroleum asphaltenes. The gamma band, a broad peak near 4.5 Å, is associated with weakly ordered paraffins. Stacks of aromatic molecules can give rise to diffraction peaks at d value higher than that of the “(002)” line. X-ray diffraction of the liquids n-hexadecane, decalin, perhydro-fluorene, 1,3 dimethyladamantane, and 1-methyl naphthalene confirms the above insights and demonstrates that diffraction can distinguish among the organic structural types “paraffinic,” “naphthenic,” and “aromatic.”