1 research outputs found
Analysis of Petroleum Aromatics by Laser-Induced Acoustic Desorption/Tunable Synchrotron Vacuum Ultraviolet Photoionization Mass Spectrometry
Laser-induced acoustic desorption
coupled with tunable synchrotron
vacuum ultraviolet photoionization mass spectrometry (LIAD/SVUVPI-MS)
is employed to analyze aromatics prepared under different conditions
from Lungu atmospheric residue (LGAR), i.e., the primary aromatics
separated directly from LGAR, and the secondary aromatics after hydrogenation
of LGAR and its resins. The mass spectra of the primary aromatics
present a bimodal normal distribution in the range of 200–900
Da, in which the relative intensity of the two peaks changes significantly
with the SVUV photon energies (9.0, 11.0, and 14.0 eV), indicating
that at least two categories of compounds with different ionization
energies (IEs) are included, i.e., polycyclic aromatics (IEs <
10.0 eV) in the mass range of 400–900 Da, and aliphatic and
alicyclic compounds (IEs close to 11.0 eV) in 200–400 Da. Also
detected in the aromatics are metalloporphyrins. Furthermore, the
mass spectra of the secondary aromatics separated from LGAR and its
resins at different hydrogenation temperatures (390, 400, 410, and
420 °C) are also recorded. The results indicate that the hydrogenation
process, especially at higher temperatures, results in removal of
alkyl-side and bridge chains in the aromatics, and the secondary aromatics
from LGAR resins contain more alkyl side and bridge chains and metal
compounds than those from LGAR