Compositional Study of Polar Species in Untreated and Hydrotreated Gas Oil Samples by Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (ESI FTICR−MS)

Abstract

Two gas oil samples, untreated feed and hydrotreated product oil, were analyzed. Both basic and acidic polar species were detected by electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry, and the detected species were characterized on the basis of their elemental compositions. Samples were real refinery samples, with one sample being a certain distillation fraction of crude oil (feed) and the other sample being a hydrotreated feed oil (product). Comparison of the compositions of untreated and hydrotreated oil provides insight into (1) compounds that are resistant to processing, (2) compounds that are removed/degraded by processing, and (3) new compounds that are produced during processing. N 1 class compounds were found to be the most abundant basic species in both oil samples. In addition, the proportion of N 1 class compounds was clearly greater in the product oil than in the feed oil, which indicates that these basic species must be resistant to removal by hydrotreatment. All basic N x O y -, N x S z -, and N x O y S z -containing compounds that were detected in the feed oil were completely removed by hydrotreatment. However, some of the O y S z compounds remained in the oil after hydrotreatment. Negative-ion ESI revealed that the majority of the acidic polar species in the product sample were N 1 compounds, which was also the predominant class in the feed sample. The second most abundant species were the O y -containing compounds. All of the O 1 compounds that were detected in the feed oil were degraded during the hydrotreatment process, as were the O 2 compounds with double-bond equivalent (DBE) values >4. Acidic N x O y -, N x S z -, O y S z -, and N x O y S z -containing compounds were not completely removed by the processing, but the relative abundances of these species were no longer significant in the product oil.

Molecular-Level Insights into Coker/Straight-Run Gas Oil Hydrodenitrogenation by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

“…Only the N2 class remains fairly resistant to hydrotreatment 40 . Liu et al 34 and Zhang et al 41 showed that N 1 class species in atmospheric residue and deasphalted oil, respectively, were more easily hydrogenated when they had high aromaticity and/or low carbon number.…”

In-Depth Analysis of Raw Bio-Oil and Its Hydrodeoxygenated Products for a Comprehensive Catalyst Performance Evaluation

“…While (−)ESI selectively ionizes polar heteroatomic species, (+)APPI is capable of a better ionization of nonpolar compounds. 21,47 The color-coded DBE vs carbon number plot corresponding to the oxygenates present in bio-oil (see Figure S1 Properties of Catalysts. The properties of the fresh ACPbased catalysts and the calcined HZSM-5 zeolite are summarized in Table 2.…”

“…These results reveal the different selectivity of both ionization methods towards different component groups. While (-)ESI selectively ionizes polar heteroatomic species, (+)APPI is capable of a better ionization of nonpolar compounds 21,47. The color-coded DBE vs. carbon number plot corresponding to the oxygenates present in bio-oil (see FigureS1…”

Hydrogen/deuterium exchange in mass spectrometry

“…Because high‐resolution mass spectrometry is very useful to analyze the crude oil samples, the combination of high‐resolution mass spectrometry with H/D‐exchange emerged as an analytical technique that can be helpful to provide structural information on individual compound. In the previous work, the speciation of nitrogenous compounds in crude oil sample by APCI HDX in combination with high resolution MS was reported .…”

“…Recently, the combination of atmospheric pressure ionization techniques have witnessed the development of high-resolution mass spectrometry for structural identification of compounds. 294,[306][307][308][309] Because high-resolution mass spectrometry is very useful to analyze the crude oil samples, 296,[310][311][312][313][314][315][316] the combination of highresolution mass spectrometry with H/D-exchange emerged as an analytical technique that can be helpful to provide structural information on individual compound. In the previous work, the speciation of nitrogenous compounds in crude oil sample by APCI HDX in combination with high resolution MS was reported.…”