Class- and Structure-Specific Separation, Analysis, and Identification Techniques for the Characterization of the Sulfur Components of JP-8 Aviation Fuel

Abstract

Methods have been described for separating the sulfur content of aviation fuels into chemical classes for identification and quantitation. These separation methods simplified the fuel matrix, which allowed non-element-specific detection methods, such as mass spectrometry (MS), to be used for sulfur detection. These matrix simplification methods also enhanced the ability of element-specific detection methods, such as atomic emission detection (AED), to identify sulfur species that are present in the fuel. Separation of a model fuel mixture, as well as several representative aviation fuels, was performed using several different methods, including classspecific chemical oxidation methods that used iodine and another that used hydrogen peroxide, and a polarity-based separation that used a polar high-pressure liquid chromatography (HPLC) column. Following separation, sulfur concentration was quantified into "reactive" and "nonreactive" classes, on the basis of the ease of transformation of the species, using chemical oxidation procedures, which also relates to the tendency for the species to undergo typical hydrodesulfurization reactions with hydrogen. These two classes were broken down further, with sulfur compounds being classified as thiol, sulfides and disulfides, thiophenes, benzothiophenes, or dibenzothiophenes. The separation and identification methods proved to be robust and transferable; the results from two independent laboratories were in good agreement. Sulfur in the jet fuels tested in this study appeared mainly as thiols, sulfides, and disulfides, as determined by gas chromotography-atomic emission detection (GC-AED), following the chemical oxidation procedures. Of the refractory sulfur compounds, benzothiophenes comprised the majority, as determined by GC-MS following the (HPLC) fractionations. Thiophenes and dibenzothiophenes contributed minor amounts to the total concentration of refractory sulfur compounds. Two main components of the benzothiophene class were identified to be 2,3-dimethyl benzothiophene and 2,3,7-trimethyl benzothiophene.

Characterization of polycyclic aromatic sulfur heterocycles for source identification

“…Sulfur compounds in aviation fuels were found to occur mainly as thiols, sulfides, and disulfides while thiophenes and DBTs are minor constituents (Link et al, 2003). Somewhat similar classes of sulfur components in a fluid catalytic cracking (FCC) gasoline were thiols, sulfides, thiophene and alkylthiophenes, tetrahydrothiophene, thiophenols, and benzothiophene (Hatanaka et al, 1997;Cheng et al, 1998).…”

Roles of surface chemistry and structural defects of activated carbons in the oxidative desulfurization of benzothiophenes

“…To improve the economics of ODS, we therefore set out to understand the role of the activated carbon promoter so as to reduce its use, thereby improving process economics. In a second published work [19] we showed that, depending on the types of sulfur compounds present in the fuel, either oxidization of the benzothiophene (BT) content [62] or removal of oxidized sulfides/disul fides/thiophenes [63] could limit overall ODS performance. Given that BT oxidation can limit ODS performance, the motivation of our ongoing research was the selection of the best carbon material for oxidation of BT compounds [19].…”

Extraction and determination of organosulfur compounds in water samples by using homogeneous liquid-liquid micro-extraction via flotation assistance-gas chromatography-flame ionization detection

“…According to the above considerations, determination of OSCs in aqueous environmental samples is necessary and provides useful information about the source of input and quality of water. The determination of OSCs in aqueous environmental samples is usually carried out by methods including gas chromatography (GC) [8,9], gas chromatography-mass spectrometry (GC-MS) [10,11] and liquid chromatography [12].…”