1 research outputs found
Determination of Structural Building Blocks in Heavy Petroleum Systems by Collision-Induced Dissociation Fourier Transform Ion Cyclotron Resonance Mass Spectrometry
Collision-induced dissociation Fourier Transform ion
cyclotron
resonance mass spectrometry (CID-FTICR MS) was developed to determine
structural building blocks in heavy petroleum systems. Model compounds
with both single core and multicore configurations were synthesized
to study the fragmentation pattern and response factors in the CID
reactions. Dealkylation is found to be the most prevalent reaction
pathway in the CID. Single core molecules exhibit primarily molecular
weight reduction with no change in the total unsaturation of the molecule
(or <i>Z</i>-number as in chemical formula C<i><sub>c</sub></i>H<sub>2<i>c</i>+<i>Z</i></sub>N<sub><i>n</i></sub>S<i><sub>s</sub></i>O<sub><i>o</i></sub>VNi). On the other hand, molecules containing
more than one aromatic core will decompose into the constituting single
cores and consequently exhibit both molecular weight reduction and
change in <i>Z</i>-numbers. Biaryl linkage, C<sub>1</sub> linkage, and aromatic sulfide linkage cannot be broken down by CID
with lab collision energy up to 50 eV while C<sub>2</sub>+ alkyl linkages
can be easily broken. Naphthenic ring-openings were observed in CID,
leading to formation of olefinic structures. Heavy petroleum systems,
such as vacuum resid (VR) fractions, were characterized by the CID
technology. Both single-core and multicore structures were found in
VR. The latter is more prevalent in higher aromatic ring classes