Elucidation of the nature of naphtheno-aromatic groups in heavy petroleum fractions by 13C n.m.r. and catalytic dehydrogenation

✍ Scribed by J. Gallacher; C.E. Snape; P.R. Dennison; J.R. Bales; K.A. Holder

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 580 KB
• Volume: 70
• Category: Article
• ISSN: 0016-2361
• DOI: 10.1016/0016-2361(91)90212-s

✦ Synopsis

13C n.m.r. spectral editing techniques have been used to determine the concentrations of aliphatic CH, CH2 and CH, groups directly in aromatic fractions from a North Sea waxy heavy distillate (vacuum gas oil) and a hydrotreated sample of this distillate. To help resolve effective and poor hydrogen-donor naphthenic groups, these fractions were catalytically dehydrogenated and re-examined by 13C n.m.r.. The results indicate that naphthenic groups in the initial aromatic fraction account for a maximum of 40% of the total carbon but only 10% of the carbon is present in effective hydrogen donors and that, in contrast to earlier structural models for heavy petroleum fractions, the naphthenic groups are relatively small comprising no more than two rings on average.