Hydrocarbon group-type separations for high aromatic fuels by supercritical fluid chromatography on packed capillary columns

Shariff, Shahidah Mohd; Robson, Mark M.; Myers, Peter; Bartle, Keith D.; Clifford, Anthony A.

doi:10.1016/s0016-2361(97)00293-7

Cited by 12 publications

(3 citation statements)

References 15 publications

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“…Column lengths of 52 cm and 98 cm were used to obtain, respectively, resolutions values of 8.4 and 17 between nC 16 and toluene, and 4.7 and 9.3 between tetraline and naphthalene, with CO 2 at 15 MPa and 45 °C, while the retention times of naphthalene were reasonable for such column lengths (6 min and 16 min respectively). Similar results with a 1.3 m long packed-column and CO 2 at 23 MPa and 45 °C were recently published by Shariff et al [41].…”

Section: Hydrocarbon Groups By Sfc: Astm Methods 5186-96supporting

confidence: 90%

Group-type separation and simulated distillation: a niche for SFC

Thiébaut¹,

Robert²

1999

Analusis

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IntroductionApplication of supercritical-fluid chromatography (SFC) for the separation of petroleum compounds really started in the '80s. SFC combines many advantages of gas chromatography (GC) and liquid chromatography (LC): its efficiency is close to GC, it works with GC detectors and involves mobile phases whose solvating power can be tuned as in LC; thus, SFC fills the gap between GC and LC. Petroleum applications are a niche for SFC because it combines GC detectors to LC-like mobile phase: high molecular-weight compounds that could not elute from a GC column elute in SFC, while universal and sensitive GC detection, such as with the flameionization detector (FID), can still be used. As a consequence, typical SFC applications [1][2][3][4] are GC-like separations, e.g. simulated distillation (simdis), and LC-like separations, e.g. hydrocarbon group-separations. However, a GC-like separation does not mean that an open-tubular column must be used. In fact, both packed and capillary columns can be used in SFC, both having their advantages and drawbacks.Simdis is a routine GC application; however, SFC is very attractive for eluting hydrocarbons having more than 80 carbons, which are difficult to elute in GC or high-temperature GC (HTGC) without cracking, because their elution can be obtained on packed or open-tubular columns at much lower temperature compared to HTGC. As SFC can also elute hydrocarbons starting from C 20 to more than C 130 , it is more a competitor than an alternative to GC.The most studied type of LC applications in the petroleum industry is hydrocarbon group-type analysis. SFC's best features for this application are the detection capabilities of FID and the properties of carbon dioxide as a mobile phase. Moreover, FID provides easy quantitation of hydroRecent advances in supercritical-fluid chromatography (SFC) of petroleum fractions are reviewed. Simulated distillation (simdis) still requires some improvements of the hardware so that routine analysis of heavy fractions can be performed. Compared to gas-chromatography simdis, SFC simdis extends the range of this application up to C 140 hydrocarbons, while multi-detection would allow the differentiation of aromatic and non-aromatic hydrocarbons. SFC has been registered by ASTM for hydrocarbon group-type analysis using carbon dioxide. It enables fast separation of aromatic and non-aromatic fractions, subfractionation of aromatics and easier quantitation than in liquid chromatography. Resins and asphaltenes of heavier samples can be backflushed from the column. The method could be further improved for better resolution and quantitation via multiple detection and more selective stationary and mobile phases (CO 2 -SF 6 mixtures for example).Keywords: SFC, simulated distillation, group-type separation, petroleum compounds Article available at http://analusis.edpsciences.org or http://dx.doi.org/10.1051/analusis:1999270681 carbon groups because of the similarity of response factors of most hydrocarbons. Replacing a LC by a SFC method is also worth con...

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Section: Hydrocarbon Groups By Sfc: Astm Methods 5186-96supporting

confidence: 90%

Group-type separation and simulated distillation: a niche for SFC

Thiébaut¹,

Robert²

1999

Analusis

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“…The reproducibility of this SFC method for the aromatic type analysis of a diesel fuel (one-ring, two-ring, and three-ring compounds) is within (0.4 standard deviations. Shariff et al 73 also studied the total content of mono-, di-, and polyaromatics in fuels using SFC on capillary columns packed with silica. The use of sc-CO 2 mobile phase permits detection by FID.…”

Section: Supercritical Fluid Chromatographymentioning

confidence: 99%

A Review on Extraction and Identification of Crude Oil and Related Products Using Supercritical Fluid Technology

Rudzinski

Aminabhavi

2000

Energy Fuels

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Crude oil, shale oil, and sand oil are all sources of petroleum and contain hundreds of compounds whose components can be grouped into four main classes such as (1) saturates (alkanes and cycloparaffins), ( 2) aromatics (mono-, di-, and polynuclear aromatic hydrocarbons (PAHs) with alkyl side chains), (3) resins (aggregates with a multitude of building blocks such as sulfoxides, amides, thiophenes, pyridines, quinolines, and carbazoles), and ( 4) asphaltenes (aggregates of extended polyaromatics, naphthenic acids, sulfides, polyhydric phenols, fatty acids, and metalloporhyrins). The latter two classes contain many species that are nonvolatile and are therefore difficult to analyze. Currently, most analyses of petroleum compounds determine species with no more than six fused rings, a paucity of polar groups, and a molecular mass of less than 600. The volatility and stability of the compounds determine whether they are amenable to analysis using standard gas chromatography/mass spectrometry (GC/MS). Hence, to determine the chemical class and identity of a number of nonvolatiles, other fluid systems with appropriate separation and detection technologies are required. These include supercritical fluid extraction (SFE), supercritical fluid chromatography (SFC), and liquid chromatography (LC). This review covers recent developments and advances in all of the above-mentioned and related techniques used to extract and identify crude oil and related products. Critical evaluation, generalization, and comparison studies have been made.

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“…Fossil Fuels, Lubricants, and Synthetic and Natural Waxes. Most of the publications in the fossil fuel area revolved around group-type separations, either for independent quantitation of the groups (78,79) or coupled to higher resolution separation methods, such as GC (80). M'Hamdi et al presented an improved group-type separation using a mixed SF 6 -CO 2 mobile phase and a silica column for stand-alone quantitation (78).…”

Section: Applicationsmentioning

confidence: 99%