PHYSICOCHEMICAL AND COMPOSITIONAL ASPECTS OF BITUMEN BEARING CRUDES AND THEIR INSTRUMENTAL CHARACTERIZATION

In India the production of bitumen is primarily based on middle-east c rude oils which normally have a right balance of bitumen constituents (i.e. asphaltenes and maltenes). In general, bitumens obtained from su ch crude oil sources have a good balance of theological and physico-ch emical properties at both low and high temperatures. Bitumen is a comp lex mixture consisting of compounds ranging from non-polar aliphatic a nd naphthenic hydrocarbons to highly polar aromatic molecules containi ng heteroatoms such as oxygen, nitrogen, and sulfur; and, several atte mpts have been reported to fractionate and characterise bitumens into broadly defined compound groups. The separation method adopted in the present study is based on the polarity of the constituent compounds co mprising the bitumen. The separated groups of compounds which progress ively increase in their polarities are saturates, aromatics, resins an d asphaltenes. In the present study three important (middle-east) bitu men bearing short residues have been selected and their detailed physi co-chemical as well elemental compositions have been reported. Each sh ort residue has been characterised by NMR and FT-IR spectroscopy metho ds and the information obtained from these analyses have been used to estimate several average structural parameters. Ultimate compositions have been determined for deducing the average molecular formulae.