Structural level characterization of base oils using advanced analytical techniques

Nadim Hourani, Hendrik Muller, Frederick M. Adam, Saroj K. Panda, Matthias Witt, Adnan A. Al-Hajji, Mani Sarathy

Research output: Contribution to journalArticlepeer-review

76 Scopus citations

Abstract

Base oils, blended for finished lubricant formulations, are classified by the American Petroleum Institute into five groups, viz., groups I-V. Groups I-III consist of petroleum based hydrocarbons whereas groups IV and V are made of synthetic polymers. In the present study, five base oil samples belonging to groups I and III were extensively characterized using high performance liquid chromatography (HPLC), comprehensive two-dimensional gas chromatography (GC×GC), and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) equipped with atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI) sources. First, the capabilities and limitations of each analytical technique were evaluated, and then the availed information was combined to reveal compositional details on the base oil samples studied. HPLC showed the overwhelming presence of saturated over aromatic compounds in all five base oils. A similar trend was further corroborated using GC×GC, which yielded semiquantitative information on the compound classes present in the samples and provided further details on the carbon number distributions within these classes. In addition to chromatography methods, FT-ICR MS supplemented the compositional information on the base oil samples by resolving the aromatics compounds into alkyl- and naphtheno-subtituted families. APCI proved more effective for the ionization of the highly saturated base oil components compared to APPI. Furthermore, for the detailed information on hydrocarbon molecules FT-ICR MS revealed the presence of saturated and aromatic sulfur species in all base oil samples. The results presented herein offer a unique perspective into the detailed molecular structure of base oils typically used to formulate lubricants. © 2015 American Chemical Society.
Original languageEnglish (US)
Pages (from-to)2962-2970
Number of pages9
JournalEnergy & Fuels
Volume29
Issue number5
DOIs
StatePublished - May 8 2015

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: We thank the Clean Combustion Research Center at KAUST and Fuel Technology Team at Saudi Aramco for funding this work under the FUELCOM program.

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • General Chemical Engineering
  • Fuel Technology

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